Science topic

Fermentation - Science topic

Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.
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I need to optimize the process of cultivating Penicillium verruculosum in liquid broth, but I don’t have enough information about the sources of carbon, nitrogen, and mineral salts for it. If you know anything or have an article about this, please let me know
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For cultivating Penicillium verruculosum in liquid fermentation, the essential components for the medium include:
1. Carbon Sources:
  • Glucose and Sucrose are commonly used as carbon sources.
  • Lactose and Maltose can also be used.
  • Glycerol is sometimes included as an alternative carbon source.
2. Nitrogen Sources:
  • Ammonium salts (e.g., ammonium sulfate, ammonium nitrate) are common nitrogen sources.
  • Peptones and Yeast extract are also used as organic nitrogen sources.
  • Urea is another nitrogen option.
3. Mineral Salts:
  • K2HPO4 (Potassium phosphate), NaCl (Sodium chloride), MgSO4 (Magnesium sulfate), and CaCl2 (Calcium chloride) are essential.
  • FeSO4 (Iron sulfate) and trace elements like manganese, zinc, and copper are added for enzyme activity and growth.
4. Vitamins and Growth Factors:
  • Biotin, Thiamine (Vitamin B1), and Pantothenic acid may be added for enhanced growth.
Optimization:
  • A C:N ratio of 10:1 to 15:1 is ideal.
  • The pH should be maintained between 5 and 6.
This medium composition supports optimal growth and biomass production of Penicillium verruculosum.
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What are suitable methods for measuring ethanol resulting from fermenting pretreated sugarcane bagasse?
If possible provide a method not suggestion and kindly don't provide AI answers
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Depending on the volume of your biomass, a cheap method would be to use a distillation process by heating the mixture and cooling it down with a condenser to isolate and collect the clear liquid, which is 96% ethanol.
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Is there anyone could share a Fed-batch fermentation protocol of S. cerevisiae? Best in English, thanks.
There is another project needs me to do a fed-batch fermentation of S. cerevisiae, however, the protocols failed from before, hence I would like to seek help from here (please)
Or could anyone alter this one?
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Hello, maybe this articles would be of your interest
Hope I've helped.
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Do you think it is possible to make this thing? Please attach your answer with some sources if possible.
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Hello
Biofuel in a simplistic definition is a substance produced biotechnologically and used as combustible. This definition matches several gaseous and liquid substances (bioethanol, biobutanol, biomethane, biohydrogen, biodiesel), produced by microorganisms, bacteria, yeasts, fungi, algae, etc.
This review could be a starting point
Hope I've helped.
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As PhD student specialized as food and industrial microbiology need to further research on bacteriocin and fermented food.
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1. Genetic Engineering of Bacteriocins
2. Optimization of Fermentation Conditions
3. Applications in Food Preservation
4. Role in Gut Microbiota Modulation
5. Biopreservation of Fermented Foods
6. Mechanism of Action and Resistance
7. Bacteriocins in Therapeutic Applications
8. Influence of Culture Media on Bacteriocin Diversity
Etc
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I have prepared a liquid broth containing Yeast (S. Cerevisiae) that i need to add from it to fermentation media of lignocellulosic hydrolysate.
I need to know based on what parameters do we add milliliters of yeast to fermentation broth?
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There is not a stright answer. When adding yeast to a mixture that's made from breaking down plant material, there are a few important things to think about. These include how much yeast you add, how much sugar is in the mixture, how acidic it is, how well the yeast turns sugar into alcohol, and how much stuff might be in there that could stop the yeast from working.If you get these things just right, the yeast will do a better job at making alcohol, which means you'll get more out of it in the end.
For most purposes, using a starting amount of yeast that's 5 to 10% of the total mixture is enough, especially if you're only interested in the final product and the stuff you're using to grow the yeast is the same as what you'll use to make the final product. Still it's important to consider the specific conditions of your fermentation. Factors like the type of yeast, what you're using to make the mixture, and how quickly you want the fermentation to happen can influence the best amount of yeast to use. Sometimes, you might need to adjust the percentage to get the best results.
However, if you want to study how the yeast grows and changes throughout the whole process, you should measure how much yeast you start with so you can keep track of how it grows.
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How we should screen out the solid material left after 90 days of fermentation in making of garbage enzyme. Is there any standardized process.
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Ultrafiltration
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I am working in fungal fermentation of soybean meal and there is bacterial growth in them at times. I am trying to quantify fungal cell counts and bacterial cells; but I haven't been able to do at real time. I can plate them and the results come after 48 hours.
I am looking at ways to see if we can do that at real time. I was trying to use automated cell counters but apparently they consider fungal debris as bacterial cells.
Any ideas?
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You could get a rough estimate of a bacteria/yeast ratio by a simple crystal violet staining and a light microscope. Then relate that to the cell counter results and later confirm with the plate technique.
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This questions aims to enquire the most appropriate way to prepare the starter culture for Pilot scale E.coli fermentation at industrial level. The biggest concern being protection against loss of clone and batch to batch variations.
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Start by inoculating a small volume (e.g., 50-100 mL) of the selected medium with a small amount of your stock culture. Calculate the volume of the pre-culture needed to inoculate your 3-5L fermentation batch. The inoculum size should be sufficient to achieve the desired starting cell density in your larger culture, typically specified as an OD or cell count per mL.
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I am working in fungal fermentation and use Nexcelom omm cell counter to quantify the cells. And I am also plating them to get the cell count after 48 hours. And there is a very low correlation between them. Has anyone faced this problem?
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Plating will give you a viable count - but is dependent on having a suitable dilution and adequate colonies to give a reliable count. The cell counter will give a total count and may include dead cells, though it may also miss cells that have lost cytoplasm. If there is particulate matter in your culture some may be mistaken for cells. And if your yeast are able to make pseudohyphae that will further increase the differences between the total cell count and the plated viable count. When working with filamentous fungi or yeast which are making pseudohyphae then the plate count will give a number of viable colony forming units (not individual cells) and automated cell counting is probably not possible.
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I'm looking for selective culture media for Akanthomyces muscarius.
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Thanks for the feedback Abhishek Anand . If you can share, follow my email: gabrielasrolim@gmail.com
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Hello! I am conducting fermentation experiments using the BioFlow 3000 bioreactor. The manual says I should use the BioCommand Lite Software to control the bioreactor and collect data. However, I couldn't find the software download anywhere. Is is available for download, and if not, are there any alternative programs I can use?
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Thank you Vladislav.
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SSF is being performed for the production of bioactive metabolites.
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According to the required amount of aeration and sensitivity of microorganism to the stresses resulting from stirring, the appropriate process and bioreactor can be selected for solid-state culture. According to the mentioned factors, various bioreactors have been introduced, and you can choose one of them according to the type of microorganism, and the amount of oxygen required. I suggest you read these books.
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Hello, everyone. When I use CICC 40553 Aspergillus niger (strain introduction can produce citric acid) to ferment corn meal and glucose, the fermentation condition is 30 ℃, 200 rpm, and the substrate concentration is 20-120 g/L. The composition of the culture medium is: the carbon source is glucose or corn flour, and the concentration range is 20-120 g/L, (NH4)2SO4 2g/L, KH2PO4 2g/L. MgSO4·7H2O 0.5 g/L. The product detected by HPLC does not detect citric acid, or the citric acid content is very low, but a large amount of oxalic acid can be detected. Do you have any ideas to solve this problem, big shots? I need a lot of citric acid.
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Formation of alcohol is initiated at very low pH, try and see maintaining pH at 5.0 to 5.5, Acid shift reaction takes place if the pH is low ; try to avoid this phase by making up the pH above 5.
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How much methanol should be added to the fermenter in which we cultivate Pichia pastoris for the purpose of heterologous enzyme production? We will add methanol continuously with the pump x ul/min.
Thanks for responses
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That will definitely depend on size of your bioreactor (you're not fermenting;). Also, in the beginning, the yeast will require less methanol than later, when it will be grown alot. One more thing - usually you grow the yeast on glycerol or something else in the beginning and start inducing after some time. So, you can slowly decrease the feeding of the first carbon source and increase feeding with methanol.
You can start with some small flowrate and increase it over time. You should check oxygen level. If it will spike once you turn off the methanol, you're adding too little or about the right amount. If it will not spike, than you have some left over methanol in your medium and should decrease the flowrate.
That's funny that you have strain BG11. We use medium BG11 for microalgae :)
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I have prepared a liquid medium for fermentation with kraft lignin in water, but the lignin was not completely dissolved. After fermentation, I am wondering about the best way to filter out the residual lignin. Would a "paper" filter with a pore size of 0.45 micrometers be appropriate for this purpose?
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How did you isolate the lignin? You may be able to get away with filter paper. I have used medium porosity fritted glass crucibles to collect insoluble lignin as well - but those are rather large particles. You may have to go as low as 0.20 microns. If you are simply mixing lignin into a solution of water - you might try mild sonication.
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Hi,
My project is about co-culture in which my producer strain will be in the biofilm state. I can't find enough literature on the same where they have used biofilms in fermentation for the production of value-added products or natural compounds. I will be glad if you can share some with me in case you find them.
Also, I would be glad to have some ideas to promote biofilm formation in E. coli quickly and robustly.
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If am getting your question correctly I think these research articles may help you
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This could involve manipulating media composition, fermentation conditions (pH, temperature, oxygen), or even strain engineering approaches.
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To maximize cellulase activity, consider integrating the following techniques: Optimize Culture Conditions, Substrate Optimization, Nutrient Supplementation, Genetic Engineering, Fed-Batch Fermentation, Strain Improvement, Enzyme Induction, and Harvesting Time.
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Yeast from a small scale fermentation was heat inactivated and stored in a refrigerator after centrifugation - about 60-70% water content.
The Yeast was planned for lipid/sterol extraction. Sadly i got sick for about a month before i could do the extraction.
Now the refrigerated sample is moldy.
Do you know what influence mold can have on such a sample - if it may be still usable after removing the mold, what the mold may have used/altered as food source to grow?
As to get to this point was quite time consuming I would prefer not to need to repeat the experiment to this point - and maybe find a way to save the sample.
I found a paper investigating the Effect of bug damage and mold contamination on fatty acids and sterols of hazelnut oil (DOI: 10.1007/s00217-016-2778-x)- where the lipids/sterol decreased. Not sure if this is similar in a liquid solution with yeast settled at the bottom.
Do you have any experience and/or advice for such a situation?
Any tip and help is much appreciated
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Well, you immediately have a problem with reproducibility if you use the samples, so it depends a lot on what you need the lipid for and what types of conclusions you would be making. If you are going to make claims about the fatty acid profile of the yeast, well the month long storage itself may have changed that in addition to whatever changes the fungus has caused. Other factors include which fungus (or fungi) are contaminating the sample, what residual growth substances were in the liquid between the yeast cells (e.g. were the cells washed before storing or are there still medium components present). How much lysis of the yeast occurred during the storage time? If all you need is some microbial lipid and you don't care what sort of profile it has and are not going to make conclusions about the productivity of the yeast it could be okay to extract your cells (might as well just leave the fungus with the yeast and extract everything). Separating the fungus from the yeast would be very challenging. I would expect the total lipid content to have gone down. Otherwise, unfortunately, you need to start over and hopefully utilising what you have learned in the first round, things go more efficiently this time.
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Based on the literature, some foam is hard to break down once produced at the end of the fermentation process, even adding some defoamer. According to your expertise, what kind of procedure we can use to prevent such foam? Increase internal pressure of fermenter? Decrease airflow and temperature by time?
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D M NAVEEN Giri You might test it to be sure. I used a few drops of octanol in 600 ltr of water and it had a major influence on coalescence (all small, christmas ball formed bubbles). Already drops of oil may spread on the surfaces in a monomolecular layer reducing mass transfer coefficient up to a factor of 10.
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Hello everyone,
I've encountered an unexpected issue while attempting to multiply bacteriophages from soil samples that were previously isolated. During the double-plate assay, I observed the formation of bubbles. Initially, I assumed they were typical bubbles caused by improper preparation of the culture medium. However, these bubbles exhibited an inhibition halo against Pseudomonas syringae, and over the course of three days, they have grown, burst, and given rise to new ones.
I hypothesize that this could be a contamination from a fermentative bacteria or possibly the bacteriophages themselves being carried by the bubbles. However, I'm not entirely certain. Any suggestions or insights into this phenomenon would be greatly appreciated.
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Hello
I think the air bubbles main cause originated from the phage source. So
I think there are some probabilities:
1- as the plaques are not Ideal plaques I mean ( not totally circular and transparent) and also not the same in shape and size , so this means its not necessary a lyric bacteriophage. It maybe a lysogenic bacteriophage which interferes the genetic material of the host and represents itself without lysis of its specific host. So it might be a lysogenic phage induces more gas production for its specific host.
2- it might be a contamination originated from phage stock , to be sure about this, as u said. You can first add 1:10 from chloroform to phage stock and centrifuge for 13 min to release all bacteriophage inside bacterial cell (in case if its lytic phage) then take supernatant and filter via .22 um filter syringe and ALSO
Perform the plaque assay on MacConky agar selective media to ensure that no contamination and in this time make a normal agar plate as control with phage and bacteria inside and observe if there are any difference
If the air bubbles appear on agar only and no macconky so it must be caused by gram positive bacteria contamination or
And if both show air bubbles it must be caused by some character of the phage and in this case, I guess its a lysogenic phage
Let me know when u get the result . And all best wishes !
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Productivity in case of filamentous fungi is heavily depend upon the morphology of the fungi. But during submerged fermentation, morphology is function of impeller design, speed and orientation of the impeller, besides other factors like pH. Right now, my fermentation 3L is equipped with the fixed blade rushton impeller due to which I have observed a lot of shearing. Is there any impeller which is suitable for the fungal fermentation specifically in chemostat mode?
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Depending on your bioreactor, biomass levels between about 4 and 8 g/L are probably okay for chemostat cultures with a filamentous fungus. If the biomass concentration is too low you are likely to have problems obtaining a steady state because of biomass attachment to surfaces and possibly also some pellet formation (depending on the species). If the biomass concentration is too high you are likely to have problems with providing sufficient aeration and uniform mixing. Dense biomass can also result in more autolysis though I don't know whether that has been investigated scientifically. Our work with Mucor in chemostats was not published, but there are publications for chemostats with Fusarium, Aspergillus and Penicillium from the APJ Trinci group, Trichoderma from VTT group, Aspergillus and Penicillium from other groups... The medium composition can affect the success of achieving good steady states. The choice of limiting substrate can affect how much hyphae adhere to surfaces and can affect the steady state. As hinted above, pH will impact the morphology and because of that the steady state...
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We have liquid waste from the by-product of molasses fermentation into glutamic acid. The problem is how to concentrate on this waste. If you have a suitable membrane suggestion, please let me know.
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Please Ref:
Study on molasses concentration ....... N. idris....2018
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I am working on bioethanol production from lignocellulosic biomass. However, I require some clarification on the methods for calculating initial sugar concentration, sugar consumption rate, ethanol yield (in g/g and g/l). Could you please recommend simple calculations or protocols?
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Sept. 21, 2023
Dear Merlin,
I will try to provide you with some information that hopefully will help you.
There are many methods for measuring sugar concentration. Some are very sophisticated, e.g., gas chromatography, HPLC, etc. If you don't have access to such instrumentation, you can use colorimetric methods. There are many of these. They use readily available chemicals and require only a bench-top spectrophotometer for analyses. One that I have used in the past was developed by Dubois et al. "Colorimetric method for determination of sugars and related substances". Analytical Chemistry, Vol. 28, p. 350-356. This is an OLD method (from 1956); however, it is still in use. It is very quick and easy to use. Requires phenol and sulfuric acid. Detects many different sugars, e.g., glucose, mannose, galactose, fructose, xylose, maltose, raffinose, etc. It is very sensitive: can detect as little as ~5 micrograms (even less) of carbohydrate (CHO). It can also detect the above sugars in polysaccharides (e.g., starch, cellulose, etc.) and oligosaccharides.
Reagents: 1) 5% phenol in water; 2) concentrated (18 molar) H2SO4.
Procedure: Add your test sample to DI-water to final volume of 1.0 mL. Then add 1 mL 5% phenol, followed by 5 mL H2SO4. (When the acid is added, the resulting solution gets VERY HOT, so hold the test tube by the top, not by the bottom.) Mix the tube contents (vortex mixer). An orange color develops very quickly. Wait until the solution is cool to the touch, then read the absorbance at 490 nm on a spectrophotometer. You will need to run a series of sugar standards for quantitation of the CHO in your samples. CAUTION!! Be sure to wear gloves, lab coat and especially safety goggles when doing the assay. If you're careful, you'll be OK.
For detection of sugar consumption rate, e.g., during a fermentation, you can take samples of the fermentation broth at various times, clarify the broth (centrifugation) and measure the sugar concentration (as above) and see how it decreases with time. You can also measure the corresponding increase in ethanol.
Calculating ethanol (EtOH) yield: Let's assume you are using yeast to ferment glucose to ethanol. Consider the reaction:
C6H12O6 ----------> 2 CH3CH2OH + 2 CO2
Glucose EtOH
If the yeast completely ferment 1 mole (180 g) of glucose, they will produce 2 moles of EtOH (2 x 46 g/mole) or 92 grams, plus 2 moles of CO2
(2 x 44 g/mole) or 88 grams. The EtOH yield is (92 g/180 g) x 100 = 51.1%. If the above fermentation is done in a 1-liter volume, you will have 92 g EtOH/liter or 92 mG/mL. If you divide the weight of ethanol by its specific gravity, that will give you the # grams of EtOH/L. If I recall, the Spec.Gravity of EtOH is ~0.79 g/mL.
From the equation and calculations above, you can see that if you start with 1 mole of hexose (e.g., glucose, galactose, etc.), the EtOH yield will be ~51.1% of the initial weight of the sugar. IMPORTANT: The 51.1% is only a THEORETICAL yield. You will NEVER get the theoretical yield. This is because during the fermentation, the yeast will use some of the sugar as a nutrient on which to grow and multiply in number, so a small amount of the sugar is never converted to EtOH . Of the total sugar, only ~93-94% of it is fermented to EtOH. This % will vary from one fermentation to another.
I hope this information helps you. If you have other questions, let me know. I will try to answer them for you. Good luck w/ your research.
Bill Colonna, Midwest Grape & Wine Industry Institute, Iowa State University, Ames, Iowa, USA. wcolonna@iastate.edu
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The experiment is to enhance high yield of bioactive compound . combination with agrowaste and bacteria
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I apologize and excuse the owner of the post. I would like to invite you to read my ebook and discover why microorganisms are so fantastic. https://www.amazon.com.br/dp/B0CF1VKKK8
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Can a fermentation system experience higher OUR values than OTR. How does this affect the process parameters.
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I have recently published a paper on this topic. I found that the relationship between OTR and OUR is given by:
dC/dt = KLa (C* - C) - 2xOUR
and that
OTR = KLa (C*-C) -OUR
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please cite some reference papers also if possible which clears this concept
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The reducing sugar is converted to bioethanol by yeast. This reducing sugar, helps in growth of yeast as well as for efficient bioethanol production. If the is no optimum concentration of sugar the bioethanol production remains stagnant. Likewise more conc. Impacts the growth of yeast ultimately reducing bioethanol production and thus affecting fermentation efficiency. So, for proper bioethanol production and fermentation efficiency, optimum sugar concentration is must.
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How to calculate pectinase enzyme activity as, we have values of OD @540 nm obtained from DNS method of different Ph and Temp of sub merged fermentation using wheat bran and citrus peel ? please let me know the calculation of total activity and specific activity by using standard curve?
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No problem
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We investigate the ability of some Streptomyces isolates to produce various bioactive molecules, primarily antibiotics. We know that fermentation conditions and extraction methods are crucial at this stage. We see that many different media and techniques are used in the literature. What do you think about the most suitable medium, incubation time, and other factors for fermentation?
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Hi, please find this recent research for Exo-polygalacturonase production enhancement:
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i am doing dark fermentation with thermophilic bacteria and nanoparticle as supplementation.
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You can compare the size of the crystalline part of the nanoparticles obtained by XRD with the sizes of the nanoparticles obtained by the scanning microscope. Get the difference. This will be the biological layer.
Nanoparticles can be calcined. The inorganic part will remain, while the biological part will disappear. You can show their weight ratio.
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Respected sir/mam, the alcohol that needs seperation must be seperated within the bioreactor( no other seperate bioreactor should be used for the extraction process other than the bioreactor with organism).
During the extraction process the safety of the organism should also be ensured.
Please kindly provide us with a solution for this at the earliest convenience. Thank you!
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Greetings Professor
Thank you for your reply
I will look into it.
Good day
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Hello everybody,
For my research I have to optimize the growth in liquid cultures of a bacterium for which oxygen availability is very important. Long story short, there will be other factors to test later (I need decent throughput) and space is an issue, so I need/want to keep working volumes low, let's say max 10mL.
I am considering batch fermentation strategies such as the use of baffled Erlenmeyer flasks; however, they do not seem to come in volumes lower than 250mL. Pre-experiments in round 24-well plates were unsuccessful, and I know that the round base plays a big role in limiting gas exchange. I have used plastic cell culture flasks with vented caps such as the ones used for eukaryotic tissue cultures and they work very well, but they are disposable (and expensive) and I am producing a looot of waste. I was wondering if anyone has had the same issue and has used, for instance, square-base plates or similar, and if it worked. Or can you please suggest alternative strategies?
Thanks in advance.
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I know I've used 125 mL baffled shake flasks (Erlenmeyer), which is definitely a good option if you're looking to reuse them. The supplier Chemglass appears to offer baffled flasks down to 50mL. I would just verify it's an appropriate type of glass for your purposes and cleaning methods. If you really like the cell culture flasks, I'm fairly sure those can also be made with glass, which could be autoclaved, but reusing them is apparently a bit contentious depending on your application (Look up "Can tissue culture flasks be reused?" by Alexis Weston on ResearchGate; one of the popular answers contains some helpful resources). However, it should be fine in the case of bacteria. I'm not sure if the vented caps can be autoclave-safe or not, so it would be good to check with the supplier for appropriate cleaning methods.
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The fermentation in question takes place in a vat of 1 cubic meter of very dense substrate and buffering the inoculum would aim at ensuring optimal pH for a longer period of time. Is it something that could be done ?
I'm very new to this field of activity.
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I see, it is indeed something to take into account, the added ions could be detrimental to the fermentation process... Thank you for your answer
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To understand my Bioprocessing module and better, I have been reading a lot about bacterial fermentation. I came across a lot of literature that either stuck to heat induction or biochemical induction for the expression of recombinant proteins in the form of inclusion bodies. However, I have also heard and read about processes that use a combination of both. For example, perform biochemical induction at 37 degree C and after 4-5 hours increase the temperature to 42 degree C and run the process for another 9-10 hours. In such cases where a combined approach is taken, is heat induction done to promote inclusion body formation? Does increasing temperature promote better IB formation or does it allow for more prolonged expression of the recombinant protein? Hit a dead end thinking about this and would appreciate any responses. Thank you in advance.
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usually decreasing the temperature can help prevent inclusion bodies formation, so increasing the temperature tends to do the opposite: https://lab.plygenind.com/how-to-prevent-inclusion-bodies-formation-in-protein-expression
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Hello all,
I am in the process of setting up an industrial enzyme production facility, initially for producing poultry feed enzymes. Does anyone have a contact of where I can procure the strains for the following enzymes? I am trying not to do R&D initially as we would like to be production ready ASAP.
Thank you!
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You can probably find them in some culture collections, or do your own screening. Some examples of culture collections are:
  • ATCC, which is the largest general culture collection in the world. It offers a wide range of biological materials for research, including cell lines, microorganisms, and bioproducts.
  • The European Collection of Authenticated Cell Cultures (ECACC), which maintains and supplies cell lines and their derivatives such as DNA, RNA and cDNA.
  • The National Collection of Type Cultures (NCTC), which maintains and supplies over 6,000 bacteria and mycoplasma strains.
  • The National Collection of Pathogenic Viruses (NCPV), which maintains and supplies over 400 viruses and viral nucleic acid.
  • The National Collection of Pathogenic Fungi (NCPF), which maintains and supplies over 4000 fungal strains.
  • The United States Culture Collection Network (USCCN), which is a consortium of culture collections that share resources and best practices for preserving and distributing microorganisms.
  • The Culture Collection at NCIMB, which is part of the UK’s Biological Resource Network and includes thousands of bacteria, plasmids and bacteriophage from various sources.
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I am working on a project to use bacterial fermentation of proteins from plant-based resources. I was wondering if anyone comment on which lactic acid bacteria i.e. Lactobacillus helveticus or L. delbrueckii has better proteolytic activity.
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Unfortunately, it's difficult to compare because of a lack of standardization between studies, but based on a couple studies, some good candidates are Lactobacillus plantarum RG14 (19.42 U/mg at pH=8), Lactobacillus rhamnosus LEY15 (~1.24 c(Glycine)/mM at 30C), and Pediococcus pentosaceus UB-8 (~5.7 U/mg at pH=5). Studies are listed below in the order mentioned:
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Under anaerobic conditions organic acids are secreted into the culture media. Also corynebacterium glutamicum is known for producing aminoacids. I am not sure if the color change from yellow to brown and finally to purple has a biological or chemical reason. Has anyone experienced such thing?
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I definitely don't have a definitive answer since I don't know the medium, setup, strain, etc. From what I can find, the color of the bacteria is yellow, and as you've pointed out, various organic acids would likely cause the pH to drop as the culture continued. My more interesting idea is that free cupric ions chelated by acetic acid may bind to proteins and turn the culture blue/purple through the biuret reaction. There are also various glutamate assays that produce a blue product, but I couldn't find information on how those work. My simpler guess is that your medium contains a colorimetric indicator, but I don't know your medium.
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We're making an E. coli intracellular expression product. In one batch of fermentation, OD was reduced by half within one hour, and phage contamination was found by post-electron microscopy. Subsequently, the entire fermentation system and workshop were treated, such as autoclave, formaldehyde fumigation, and ozone disinfection. Subsequent fermentation showed no contamination. But bacteriophage contamination was found again this week. Would like to ask how to do follow-up prevention? We found that the two fermentation contamination were both cultured at 30 degrees, while the intermediate culture at 37 degrees did not show contamination. Are there any temperature-sensitive phages?
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I think it more likely the issue is not the difference in temperature but rather moving from the intermediate culture to the large scale. Are you going from a flask to a fermentor? It may be something in the fermentor pipeline is permitting the phage contamination.
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Hello, so i am scaling up a 10 L biorector to 1000 L bioreactor for enzyme production using corncob-based media. The product increased, but there's a lot of excess media left in the product. So, i want to minimize the media impurities before purifying the product. What should i assess regarding this matter? Thank you
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The key for fermentation scale up is to keep some key parameters the same or proportional. These important parameters may include mixing times, power to liquid volume ratio, oxygen transfer coefficient etc. The following are some useful article to guide fermentation scale up:
Article Scale-up of Industrial Microbial Processes
If there was no excessive medium at small scale, then the reason for excessive media at scale up is likely due to the unproportional scale up that changed some key parameters.
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Hello all,
I am in the process of setting up an industrial enzyme production facility, initially for producing poultry feed enzymes. Does anyone have a contact of where I can procure the strains for the following enzymes? I am trying not to do R&D initially as we would like to be production ready ASAP.
Thank you!
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There are a bunch of places where you can get microbial strains for making industrial enzymes. Here are a few options:
1. Culture Collections: Many countries have these collections where they keep a bunch of different microbial strains, including ones used in industries. These places usually give out strains to researchers and businesses. Some examples are the American Type Culture Collection (ATCC), the National Collection of Industrial Food and Marine Bacteria (NCIMB) in the UK, and the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) in Germany.
2. Biotech Companies: Lots of companies that work in biotechnology focus on developing microbial strains and offer all sorts of strains for industrial purposes. They might have their own unique strains or genetically modified organisms made specifically for making enzymes. Some examples of these companies are Novozymes, Genencor (a division of DuPont), and Codexis.
3. Research Institutions: Universities, research institutes, and government labs often have collections of microbial strains for research. Some of these places might be willing to provide strains to businesses or collaborate on projects involving enzyme production. It could be helpful to get in touch with relevant departments or researchers in this field to access these kinds of strains.
4. Online Strain Marketplaces: There are online marketplaces that focus on selling microbial strains and related stuff. These websites connect people who want to buy and sell strains, so you have a lot of options. One example is the ATCC Microbiology Marketplace, where you can find all kinds of microbial strains.
5. Industrial Enzyme Suppliers: Companies that make and sell industrial enzymes might also offer the matching microbial strains for people who want to make enzymes themselves. If you have a specific enzyme in mind, you can reach out to these enzyme manufacturers and ask if they have the strains you need.
When you're getting microbial strains, it's important to think about things like whether the strain will work well with your production process, if it's genetically stable, and any rules and regulations you need to follow. Also, make sure you're following the safety and intellectual property rules related to working with microbial strains.
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Is a lactic acid bacteria strain sourced from plant sources is more suitable for fermentation of plant proteins compared with a dairy sourced strain?
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Lactococcus lactis suitable for the production of heterologous proteins
Pichia pastoris yeast suitable for the production of recombinant proteins
Okara fermentation and vegetable burger production with okara fermentation and vegetable burger production by Rhizopus oligosporus mold
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As a guest editor of special issue on Enzyme in Biorefinery in the journal Fermentation (https://susy.mdpi.com/academic-editor/special_issues/process/1215191) I invite submission of the articles related to the theme of this special issue.
The special issue is aimed to collect articles describing role of enzymes in biorefinery processes.
Fermentation is an open access journal and hence incurs article processing charges.
Some discounts in APC are available.
I will be delighted to respond to quries in this regard.
Best,
Sohail
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D M Naveen Giri Yes you are right. APC is applicable. As you can see in https://www.mdpi.com/journal/fermentation/apc. However, I have very limited option to offer a 50% discount in APC. You need to contact me at msohail@uok.edu.pk for further information. Thank you
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Hi!
I'm currenty transitioning into using a microplate reader. Right now, I use DNS to determinate reducing sugars from a fermentation supernatant. Recently the lab acquired a microplate reader and I would love to use it for all my analysis. Any sugestions?
Thank you!
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You have scope
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Therapeutics such as probiotics exert a beneficial effect on host gut microbiota after consumption and may be capable to prevent several diseases such as Alzheimer’s disease. Fermented dairy foods, cheese whey and buttermilk whey offer suitable matrices for the growth and viability of probiotic microorganisms and are potential sources for the development of probiotic dairy-based beverages. The literature shows that the heterogeneous food matrices of non-dairy food carriers are the major constraints for the survival of the probiotics and the use of antioxidants in yogurt manufacture. Dairy consumption such as sour/fermented milk, yogurt, cheese, butter/cream, ice cream, and infant formula need to be assessed for the content of microbial diversity. The role of fermentation, freezing/thawing, room temperature modification and probiotic shelf life may have a critical effect on the generation of LPS from gram negative bacteria that may lead to dysbiosis. The association between high fat/high cholesterol diets have been shown to be linked to the increased incidence for Alzheimer’s disease (AD). The literature shows strong evidence with relevance to changes in cholesterol metabolism and transport that is associated with AD pathogenic processes. The safety of probiotic therapy for AD patients requires investigation with relevance to the induction of dyslipidemia and the release of bacterial lipopolysaccharides and amyloid beta from gram-negative bacteria needs to be controlled in these probiotic formulations.
RELEVANT REFERENCES:
  1. The role of Microbiota in the pathogenesis of Alzheimer’s disease. https://www.researchgate.net/publication/370691497_The_role_of_Microbiota_in_the_pathogenesis_of_Alzheimer's_disease
  2. Food and Nutrition cause liver and brain diseases ... - Atlas of Science: Another Veiw on Sciencehttps://atlasofscience.org/food-and-nutrition-cause-liver-and-brain-diseases-with-diabe... Mar 11, 2016 –
  3. Bacterial Lipopolysaccharides and Neuron Toxicity in Neurodegenerative Diseases. Neurology Research and Surgery. 2018; 1(1): 1-3.
  4. Overnutrition Determines LPS Regulation of Mycotoxin Induced Neurotoxicity in Neurodegenerative Diseases. Int J Mol Sci.2015;16(12): 29554–29573.
  5. Functional Foods and Active molecules with relevance to Health and Chronic disease: Editorial. Functional Foods in Health and Disease 2017; 7(10): 833-836.
  6. Food Quality and Advances in Pharmacological Management Prevent Mitochondrial Apoptosis and Epilepsy Induced Stroke. Research and Reveiws: Neuroscience. 2018;2:7-9.
  7. Food quality induces a miscible disease with relevance to Alzheimer’s disease and Neurological diseases. J Food Research, vol. 5, pp.45-52, 2016.
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Dear Emad Hussein,
Thank you for this very important answer.
Ian James Martins (PhD, D.Sc and Dr.Med, Doctrin de Science, Honoris Causa) https://orcid.org/0000-0002-2390-1501
ABCD Wall Life Journey and career: https://youtu.be/cYy4OmTkKvY?t=21
INDEPENDENT SCIENTIST (Pride of Australia) https://sites.google.com/site/internationalindexing/advisory-board International Press Release July 2020 Dr. Ian James Martins DSc (Honoris Causa) Doctrin De Science Award Honoris Causa International Press Release September 2019 World's Famous Scientist Dr. Ian James Martins from Australia conferred with Honorary Degree of Doctor of Science for Outstanding Scientific Contribution in Nutrition. Dr. Ian Martins from Australia conferred with Honorary Degree of Doctor of Medicine for Outstanding Scientific Contribution in Diabetes]. (Honoris causa) Fellow of International Agency for Standards and Ratings (IASR)
Division for Certification and Accreditation
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Are all probiotics can make fermentation?
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No, not all probiotics can initiate fermentation. Probiotics are live microorganisms that, when consumed in adequate amounts, can provide health benefits to the host. While some probiotics are involved in the fermentation process, not all probiotic strains have the ability to ferment.
Fermentation is a metabolic process where microorganisms convert carbohydrates into other products such as alcohol, organic acids, or gases. It is commonly used in the production of various foods and beverages like yogurt, sauerkraut, and kimchi.
Certain probiotic strains, such as Lactobacillus and Bifidobacterium species, are known to have fermentative capabilities. These strains can break down complex carbohydrates into simpler compounds, producing lactic acid and other metabolites as byproducts. This fermentation process contributes to the tangy taste, texture, and preservation of fermented foods.
However, many probiotic strains do not possess the enzymatic machinery required for fermentation. These strains may still offer health benefits by interacting with the gut microbiota, modulating the immune system, or producing antimicrobial substances. Their mechanisms of action are often different from fermentation.
It's important to note that the specific properties and abilities of probiotics can vary depending on the strain and species. Therefore, not all probiotics can be expected to have the same fermentation capabilities.
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India’s Green House Gas emissions calculation of livestock specifically enteric fermentation. These queries are related to -
• Methodology used to calculate emission from livestock in India
• What are the parameters used to calculate emissions from livestock – considering different - sub category of cattle and buffalo, breed, non-descript animals, feeding practices and rearing practices across India
• Emission factors – how are these arrived at for different cattle and buffalo breed including non-descript, what were the formula and sub formula used
• Details of various parameters used in the above formula and sub formula to arrive at the emission factor for each category
• Details of any model that is currently being used for emission factor estimation
• State wise enteric fermentation data for the last five years based on the emission factors currently used
• Activity Data – details of the activity data used to calculate the enteric fermentation
• How are we calculating emission for different rearing practices, stall fed, stall fed and grazing, grazing or pastoral and their details
• How are we calculating emission for the non-descript cattle and buffalo
• Are we factoring in the draught power in the emissions
• What are the factors contributing to the Uncertainty as per BUR3, what are the ongoing efforts to reduce these uncertainty
• Details of GHG inventory improvement practices adopted by the country
• Details of the effects of adaptation and mitigation actions related to productivity improvements in the livestock sector is adopted to estimate GHG emissions and its sustainability
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The methodology used to calculate emissions from livestock in India typically involves the use of standard emission factors and activity data. These factors take into account the amount of greenhouse gases emitted per unit of activity, such as per unit of animal feed intake or per unit of manure produced.
In India, the most commonly used emission factors for livestock are based on the Intergovernmental Panel on Climate Change (IPCC) guidelines. These guidelines provide default emission factors for different types of livestock and different stages of production, such as enteric fermentation (the digestive process that produces methane) and manure management.
Activity data, such as the number and type of livestock, the amount of feed consumed, and the management practices used, are collected from surveys and other sources. These data are then combined with the appropriate emission factors to estimate the total amount of greenhouse gas emissions from livestock in a given region.
It is important to note that emissions from livestock can vary widely depending on a number of factors, including the type of animal, the diet, and the management practices used. Therefore, accurate estimation of emissions requires detailed and up-to-date data on these factors.
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Hello,
End of last year I have developped an indirect ELISA method to detect a couple of caseins in fermentation supernatants. It worked great until a couple of weeks ago.
Since then, for each plate we are running (6 plates as of today), their are black aggregates developping after the addition of H2SO4 (stop solution). They are increasing with time starting from the addition. They are not present after incubation with TMB.
Does anybody experienced the same thing? And/or does somebody knows what it could be and how to fix it?
Thanks in advance,
Julie
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Dear Alireza,
thanks for your answer. I'll try that, it migth help.
We are using the same TMB reference for the last 6 months and the aggregates have been appearing since 3 weeks without changes in the protocol. The changes are different lot of plates and TMB. Secondary antibody seems to participate to these aggregates formation (tests of last week), even if we are using the same bottle since the begining.
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If the media is placed in a shaker during the fermentation time, ethanol production increase or decreae??
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From my opinion, S. cerevisiae does not require agitation for ethanol production. You may perform an experiment with and without agitation to know the result. Thanks,
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Dear all,
So I'm running some experiments where I will need to record growth profile data, and collect samples for glucose, ethanol and volatiles analysis. My strategy is always to use use fresh cells from a plate (so, streaked in the afternoon to fresh plate, let grow overnight at 29 degrees, and inouclate pre-culture next day, 8 hours, start culture by dilution, calculating a certain Od next day based on the 2x time). When diluting the pre-culture, I assure that they are in the beggining of exponential phase, to avoid any kind of lag-phase. I send you a figure where there are curves using the same strain and same media, but with different final biomass concentrations. From my pre-culture, I also tested dilluting the strains to a culture or actually put them in the microplate reader. I observed that, from the same pre-cutlure, when cells are dilluted something happens, since on the microplate reader, where I just loaded the pre-culture directly, cells grow like in curve 1. However, this does not happen every time, as you can see in curve 1. On curve 1, cells were treated the same way as in curves 2 and 3, but they grew just fine. Additionally, we also measured glucose. As you see, on cultures where growth arrest occurs faster and earlier, glucose takes much longer to be consumed. The growth rates between all the curves, however, are equal, it's just the exit from exponentil growth that occurs earlier. Of curse, for the cutlures 2 and 3, the glucose concentration when cells shift from exponential growth is quite high. I always use same flasks, same amount of media per flask (1/5 of the volume of the flask), fresh cells, etc. I have no clue why are they exiting exponential growth so fast and early. Hope somebody can help me! Thank you in advance.
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The biomass are different from fermentation to fermentation batches on the basis of growth kinetics : Structured & Segregated Model. Firstly, in Structured model-Growth of cells are different in terms of systhesis of biomolecules, enzymatic reactions, metabolism- as a whole the cells are considered as multicomponent system. Secondly, in Segregated model of growth kinetics the cells are treated as heterogenous in terms of size, metabolic state. If your fermentation system is continuous, then you can make all the cells grow uniformly thereby exiting the exponential phase evenly by regulating the limiting substrate eg., N2, thereby all lag phase cells can catch up with the log phase cells. One of the disadvantage of batch fermentation is that the cells exit from the exponential phase cannot be regulated due to the complexity of Structured and Segregated growth kinetics.
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In recent years, fermentation has evolved into a prominent method for the production of bioactive peptides particularly for the development of novel nutraceuticals and functional foods. Microbial proteases breakdown protein into peptides during fermentation, but what happens to the other non-protein components of the fermentation medium? Can microorganisms be grown solely on protein substrate? Milk fermentation, for example, results in the breakdown of milk proteins into peptides; but what about other components? Bacteriocins, which are antimicrobial peptides synthesized by ribosomes rather than milk proteins, are also produced by lactic acid bacteria. Can we claim bioactivity of fermented milk due to bioactive peptides in this case? Other metabolites and bacteriocins have bioactivities as well.
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yes , fermentation is one of the most popular method for production bioactive peptides. There are three methods, Enzymes digestion (in vitro), food processing and microbial fermentation. Identification of these bioactive peptides is the most difficult part.
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Hello everybody,
I'm currently growing E. coli in bioreactor and I have experience only with P. pastoris in bioreactor, so I'm not sure, how should it behave. With Pichia, one can try hard to imrove the conditions and it will grow very well to very high cell density (something like OD600 of hundreds), so I had similar approach with E. coli.
I usually grow E. coli (in flasks) in LB medium supplemented with 0.1M K-phosphate pH 7.0; 1% glycerol; 2mM magnesium.
I grew it for the first time in this medium, but the pH shifted up to 8.x after switching the temperature to 18°C (after induction). We thought it was because of the phosphate, although from what I found on the internet, the phosphate buffer shall not be so much sensitive to temp change as other buffers. Anyway, we grew it without the phosphate the second time, but the pH increased anyway (not that much though). Moreover, it was slowly increasing over time, rather than decreasing. It was about 7.2 in the morning (maybe more). What could be the cause of the pH increase?
Second- what is the usual OD600 after overnight growth in bioreactor? The first time we got around 8, but the pH was slowly increasing. At that time I thought it's because of cell lysis, but now in retrospect, it could be related to the changes in pH as mentioned above. The second time we got OD600 around 3, but it was after shorter time (because we thought it's lysing) and the culture grew slower in general in comparison with the first one.
Thank you for your suggestions.
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Hi
We've got the same problem with OD600 after overnight growth in bioreactor namely after
12 h we've reached 8 ,
7 and 6 durin
g three day respectively . We want to establish DO cascade by means of glucose dosage by pump , but maybe this is wrong solution we've no enoug experience in this subject ( maybe 'll be better we have to set up ph in cascade instead of DO )
Thank you for your suggestions.
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I require small amounts of sodium lactate from a fermentation broth for laboratory exercises. I would like to avoid evaporating off a lot of water so tried precipitation. Most catalysts for this were not appropriate for the end use as they were slightly toxic.
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What is the mechanism by which the microorganisms in the pulp during the fermentation process of cocoa/coffee affect the quality of the bean and/or cotyledon?
If it is an indirect influence, what is the significance of inoculating fermentation starters?
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Hi Haode,
we studied the role of different microbes during cocoa fermentation at the level of their carbon metabolism. Mainly, 3 species are involved: lactic acid bacteria, yeast and acetic acid bacteria. They all depend on each other and their interplay is responsible for the aroma development during fermentation. Have a look at the following publications:
Best
Michael
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I did ethanol production using 50g/L of glucose and xylose in fermentation broth. Now need to find ethanol productivity, their theoretical yield and fermentation efficiency, also consumption of pentose and hexose sugars. Kindly help me to get clear calculation (any papers or protocols) for all of this especially ethanol productivity calculation
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Hello, Merlin Sobia as I understood, you about the ethanol 7.2 %?
7.2% mean 7.2g in 100g or 72g/l
So, if you receive 72g/l ethanol from 50+50=100g/l monosaccharides solution it above the level of theoretical calculation with yield 72%:
If we carucate by equation.
Glycose = 2C2H5OH+ 2CO2 +Q (Energy)
Xylose = 1.66 C2H5OH+ 1.66CO2 +Q (Energy) (same as glycose)
by molecular weight glycose equation will be
180g/mol=2*46g/mol+2*44g/mol
at 100% conversation you will receive 92g/mol (51.2%) ethanol and 88 g/mol (48.8%) C02
100%= 51.2% + 48.8% so the theoretical maximal yield for ethanol is 51.2%
From 100g/l monosaccharides maximum the 51.2g/l ethanol can be formed.
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I would like to know the existence of possible ways to separate mycelium after the solid-state fermentation of waste material.
I know about the membrane culture process for mycelium but couldn't find a good source/way to separate mycelium biomass from solid-state fermented materials other than agar mediums.
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I think you found the best solution in the isolation of mycelia on agar medium from solid-state fermentation products on agar plates, If you see that your culture sporulating during fermentation you can use heat treatment of the sample before isolation to exclude growing any non-spore-forming microorganisms during isolation.
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I'm trying to determine an anaerobic bacterial cell growth curve. The substrate of the medium is lignocellulose. I also add some dark soluble substance in the medium. So I can't measure OD. I tried to measure the total protein of bacterial. But I can't fully washed the dark soluble substance absorbed on the cellulose. It had a great influence on the method of protein measurement, including BCA, lorry and bradford.
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Have you tried gravimetry, counting chamber or coulter counter? I can't suggest you something specific since I don't know what the "dark material" is, but I would say a coulter counter is a good option. You could also try to remove the "dark material" with different solvents, although your cells may suffer.
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How can we predict the bioethanol yield from simulated fermentation parameters concerning yeast fermentation of lignocellulosic biomass by using recently developed machine learning techniques of Artificial Intelligence technology? Please define the research question Clearly articulate the research question you want to answer with your machine learning models.
#Artificial intelligence #ML Models
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he production of bioethanol is a current topic raised by scientists, technologists, and representatives of fuel companies in the European Union who are working on satisfying the percentage share of this biocomponent in conventional fuels. (PDF) Use of Machine Learning Methods for Predicting Amount of Bioethanol Obtained from Lignocellulosic Biomass with the Use of Ionic Liquids for Pretreatment. Available from: https://www.researchgate.net/publication/348248522_Use_of_Machine_Learning_Methods_for_Predicting_Amount_of_Bioethanol_Obtained_from_Lignocellulosic_Biomass_with_the_Use_of_Ionic_Liquids_for_Pretreatment [accessed Feb 19 2023].
Regards,
Shafagat
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The conversion of sugars into bioethanol occurred in the fermentation medium. However for GC analysis, in capillary or packed column, water is biggest enemy for instrument. still in need of ethanol quantification so kindly suggest methods to remove or reduce water content without affecting ethanol in the fermentation medium
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@Jonas Friberg Thank You.
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can anyone help me in the recovery of citric acid from fermentation broth
I want to recover citric acid using Ca(OH)2 when add Ca(OH)2 in it. how much Ca(OH)2 i should add to get pure calcium citrate and at which temperature i should heat it to precipitate Calcium citrate as calcium (OH)2 is also slightly soluble in water. there is a chance of preciptation of Ca(OH)2
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As for the industrial-scale calcium precipitation process, when a one molar amount of organic acid is converted, an equal amount of Ca(OH)2/CaCO3 and H2SO4 are consumed, and low valuable calcium sulfate is formed [Lee SC, Kim HC. 2011. Batch and continuous separation of acetic acid from succinic acid in a feed solution with high concentrations of carboxylic acids by emulsion liquid membranes. J. Memb. Sci. 367: 190-196, Pazouki M, Panda T. 1998. Recovery of citric acid: a review. Bioprocess Biosyst. Eng. 19: 435-439.].
Regards
Vit
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I was wondering if it's possible to evaluate the amount of oligosaccharides (stachyose and raffinose) in soybean meal using the dinitrosalicylic method. I have dinitrosalicylic acid and alpha-galactosidase (enzyme that digests oligosaccharides), but I'm unsure if this method is applicable.
Any insight is appreciated.
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2/9/23
Dear Linoy,
I don't think that DNSA would be useful for you. This reagent is used for detecting reducing sugars, i.e., sugars that have a free carbonyl that can react w/ DNSA. E.g., in the case of glucose (an aldohexose) the carbonyl is is an aldehyde at carbon 1. With fructose, the carbonyl is a keto group at carbon 2. Neither raffinose nor stachyose are reducing sugars, so they will not react w/ DNSA. I'm not sure if using alpha-galactosidase will help you. This will cleave 2 galactose residues from stachyose and 1 galactose residue from raffinose releasing sucrose. Galactose is a reducing sugar and can be detected with DNSA. However, of the total galactose quantitated, I don't think you will be able to determine what % came from raffinose and what % came from stachyose.
A better way to do this would be to use chromatography, e.g., HPLC. Raffinose is a trisaccharide (mol. wt. 504), whereas stachyose is a tetrasaccharide (mol. wt. 666). These are sufficiently different in molecular weight that they can be separated by HPLC using a molecular sieving column.
I hope this information helps you.
Bill Colonna Iowa State University, Ames, Iowa, USA wcolonna@iastate.edu
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Hello,
I would like to come up with the fermentation volume required for an enzyme manufacturing project.
I have the volume/concentration necessary and I have the fermentation activity of the strains.
Ex. If the fermentation activity of the strain is 5000 u/ml and if I need to produce 20000 Kgs of enzyme with an activity of 50000 U/g then what would be my fermentation volume?
TIA for all the help
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20,000 kg x 50,000 U/g x 1000 g/kg x ml/5000 U = 200,000,000 ml = 200,000 L
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Why the productivity of Exponential Fed Batch Fermentation is Lower than that of linear Fed Batch Fermentation ?
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Is it possible to explain in more detail what do you mean about exponential and linear fed batch fermentation in your process?
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dear, can anyone guide me what will be protocol for the quantification of citric acid and oxalic acid from the fermentation broth using titration technique. means quantification from a mixture of oxalic and citric acid.
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About pH or titration of mixed acid solutions at RG:
About the titration of a mixed phosphoric acid / sulfuric acid aq. solution with sodium hydroxide aq. solution; cf. my posts at:
About the pH for sodium acetate / acetic acid solutions with added hydrochloric acid; cf. my posts at:
About the pH of mixed lactic acid /sodium lactate and acetic acid / sodium acetate solutions or buffers ― also with strong monoprotic acid added; cf. my posts at:
About the pH of mixed H2SO4―HNO3 aq. solutions:
On the pH of mixed H2SO4―HCl and H2SO4―HCl―HI aq. sol.:
About mixed citric acid / sodium citrate with nitrous acid / sodium nitrite solutions or buffers:
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When the recombinant E. coli was cultivated in a 3L fermenter, the growth of the bacteria was normal before induced by lactose, and the parameters such as pH and DO were normal. But about 5 h after induction, the bacteria would autolyze at a fast rate, and the final OD600 is also low.
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The possible reason for this is that the expressed protein is toxic to E. coli, or phage infection.
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Is there any laboratory test that I can use to identify if two or more microorganisms will be compatible as a mixed culture for fermentation purposes?
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compatibility of two microorganisms in a mixed culture can also be justified by streaking both of them over same plate of favorable growth media. you just have to streak both the cultures making plus or cross sign with the help of inoculating loop containing your cultures over to the same plate so that both the cultures interact at single point. if first culture is not inhibiting the growth of second culture at meeting point then it can be interpreted that both microorganisms are compatible. you can perform this experiment for more than two cultures also in a single plate. Hope this is going to help you.
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Hi everyone,
How aeration and agitation can influence the mixing of liquid in vortex fermenter?
what are the other significant factors that can influence the mixing capacity in vortex fermenter.
With regards,
Dipak Das
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. 1993;58(4):331-6.J Chem Technol Biotechnol
doi: 10.1002/jctb.280580404
In general mixing is improved by energy input. In a STR input comes from stirring and gas input. In a vortex fermentor the gas input comes from the system by stirring, so I assume its input does not count. However, gas entering the stirrer reduces the power input by stirring.
The dependency on power input is small (power 1/3).
In STR's tangential circulation is reduced by baffles to improve mixing by turbulence rather than by the circulation that is less effective to create turbulence. But inserts have a negative effect on the gas sucking, which however might be compensated by increasing the stirrer power input.
I could not reach the paper mentioned above, just the abstract, but that promised evaluated data that may be interesting. Also you could have a look at our general
though vortex fermentors are not discussed.
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Dear All,
I am looking for a simple spreadsheet for calculating the feeding regime for biomass production in a fed-batch mode.
Basically, I am growing baker's yeast and looking for a simple spreadsheet that I can provide my volumes, substrate concentrations, specific growth rate, starting biomass and target biomass So I can get feeding rate and time of fermentation required without going through the complex calculations and equations that I am not good at. I am using sucrose and 10L steered/controlled bioreactor. Anyone can help with this? I will be very much grateful.
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Dear Abdelrahman,
I assume you want to feed exponentially. Use the following formula to calculate the feed rate at any time in the feeding phase:
F(t) = (µ_set / Y_xs + m) * ((V_0 * X_0 * exp(µ_set(t-t_0))/S_0)
with
F(t) - time-dependent feed rate [mL/h]
µ_set - targeted specific growth rate [1/h]
Y_xs - biomass yield [g dry cell weigth / g substrate]
(m - optional maintenance term [g substrate / g dry cell weight / h]
V_0 - reactor volume at the beginning of the feed phase [mL]
X_0 - biomass concentration at the beginning of the feed phase [g/L]
t-t_0 - time span between feed start and current process time [h]
S_0 - Substrate concentration in the feed medium [g/L]
If you want to calculate the time it takes to reach a certain biomass level just rearrange and solve for t-t_0.
Good luck
Michael
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I am planning to produce a recombinant protein by fermentation using Pichia pastoris (mut+) as the host and methanol as the inducer/carbon source at the protein production stage. For the fermentation, I am looking at the scales at 1 L, 20 L and possibly 200 L, with which the main challenge is how to safely manage the flammable and toxic methanol within the lab. When working with the 1 L bioreactors, I can place 1-2 bioreactors and methanol in a fume hood. But I have no idea on how to scale up when both the bioreactors and the volume of methanol to be used are beyond this option with a fume hood. I have searched online for a solution or reference, no expected information has been found so far. Though some people just mentioned using methanol is a risk, no people talked about the solutions for the management of methanol during fermentation. So I present here the challenge I have now, and If I could get some ideas or suggestions from the colleagues here who have worked or have been working with P. pastoris and methanol for scale-up fermentation, that will be very graceful. Thanks in advance. Shuguang
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Hi Shuguang Zhang , I am not sure if my suggestion would help. I have dealt with experiments set up that involve volatile gas vapor. Usually, we have an exhaust outlet attached to the bioreactor. It's either we connect to a cold trap/condenser to recover the vapor or you can try filling up with 4A Molecular sieves@ to absorb methanol.
I hope this helps.
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I am currently completing a design project, part of which requires cellulase to produce glucose for fermentation. 37 tons/hr of cellulose is the input for the process. We have found that 10 FPU/g cellulase is feasible for the process. How do I go about working out exactly how much cellulase we need? I don’t particularly understand FPU.
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You can increase the FPU of cellulase to 12, 15, or 20 FPU/g. By which you will know the correct amount of cellulose.
If you want to FPU calculation you could follow this link:
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Biochem major here. Just a bit perplexed as to why my Kimchi and Sauerkraut produce bubbles when this is not a direct by-product of lactic acid fermentation. Are other bacteria involved, or perhaps ethanoic fermentation?
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In the preparation of sauerkraut and kimchi, there is no homofermentative fermentation to lactic acid, but other fermentations take place where the product is e.g. ethanol, acetate and also carbon dioxide. The process is heterofermentative and therefore carbon dioxide is also produced.
Regards
Vit
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I want to culture the different lactic acid bacteria that are present in fermented vegetables, i saw that MRS medium is mostly selective for lactobacillus, but there are many more types of bacteria present in the fermented vegetables. Would it be possible to grow the whole array by simply removing sodium acetate? How big is the risk of contamination from other sources?
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I took this direct from one of the directions for using MRS agar:
"Lactobacilli MRS Agar is used for the cultivation of lactobacilli and is not intended for use in the diagnosis of disease or other conditions in humans. MRS Agar is a medium for the cultivation and enumeration of Lactobacillus spp. Originally developed in 1960 by de Man, Rogosa & Sharpe, the medium is suitable for most lactic acid bacteria and is intended as a substitute for Tomato Juice Agar. When acidified to pH 5.4 MRS Agar can be used to enumerate Lactobacillus bulgaricus in yogurts. Nutrition is provided by a mixture of carefully selected peptones, glucose, beef & yeast extracts while Tween® 80, magnesium and manganese sulfates act as growth stimulants. Selectivity against streptococci & molds is provided by ammonium citrate and sodium acetate. Used at low pH, ammonium citrate allows growth of lactobacilli while inhibiting a number of other microorganism groups. Occasionally, sterilization of this medium at 121°C for 15 minutes, in some autoclaves, may cause the pH to fall outside of the specified pH limits 6.4 +/- 0.2. In these rare cases, adjustment of the medium using acetic acid or sodium hydroxide is recommended."
As you can see taking out sodium acetate will leave ammonium citrate in there as a selective agent. You would have to take both of them out but you then risk getting moulds. Considering the pKa of lactic acid to be about 3.8. I would think using a medium like Muller Hinton but adjusting the pH to about 4.5 and temperature 40 to 45 degrees would select for lactic acid bacteria.
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I want to dissolve heptadecanoic acid for microbial fermentation at around 5g/L in the fermentation broth. I dissolved it in ethanol however when I added fermentation broth at 5 g/L of the heptadecanoic acid, it was precipitated. How can I use the final concentration of 5g/L of heptadecanoic acid in fermentation broth?
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How you can if heptadecanoic acid is highly hydrophobic. If you want to fing degradation activity use solid media where you can use heptadecanoic acid.
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I was about to do R. oryzae fermentation in 500 mL flask. The Culture medium (g l−1): corn stover hydrolysate 22·4, KH2PO4 0·6, MgSO4·7H2O 0·5, FeSO4·7H2O 0·0088, ZnSO4·7H2O 0·11, urea 2.
it was all fine until i autoclaved the medium for 15 mins, there was white insoluble precipitate.
and the fermentation was slow (72h of incubation in waterbath shaker, 100rev/min), rather than a big ball of mycelia formed, it was like cloudy small dots mycelia. I have to extract the mycelia and the amount of those cloudy dots mycelia was too small.
is there any way to solve this?
additional info: the hydrolysis of corn stover was carried by 2h of autoclaves in 2% H2SO4 with the ratio of corn stover : sulfuric acid (1:10).
after that, detoxification was done by adding 2N of Ca(OH)2 until the pH of 8, centrifuged, and the supernatant was taken to be the carbon source.
I didn't adjust the hydrolysate pH bcs when the medium is done, the overall pH was 5,6 and I thought that's a pretty ideal pH.
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Haloo Yazid, According to my experience to make a medium, I need to separate all components. First just glucose, the second mineral in one flask (you do not need to separate all minerals), and the last other components in one flask.
If you used hydrolysate as a source carbon, I do not recommend using an autoclave because it can cause a browning reaction or can make the hydrolysate become dark. You can use a vacuum to remove all contaminants. Maybe you can read my article about ethanol production by using hydrolysate. If I am not wrong, there is information about the medium.
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The tested species are growen in broth and they incubated for fermentation optimicaly
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Hi Sawsan
The extraction might depend a little on the properties of the expected molecules.
Do you expect your ABs as dissolved molecules in water or more in hydrophobic form, attached to the Biomass? Do you have ionic groups, basic, acidic or ampholytic?
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Hello
The Fermentor is in the form of fed batch. In primary and secondary inoculum, growth is normal, but after feeding (about 1/6 of that) about 4 hours later, The fermentor get foamy, the morphology of the cells becomes round and the cells burst and OD reaches to 5 (These events happen in less than 5 minutes). What could be the reason?
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Hello Habibeh
Beside of a natural lysis effect, you could check if a bacterial contamination is responsible for an increased lysis in your system
Mostly E.coli-Antibiotic-based systems are not carried out under very strict steril conditions. Autolysis of E.coli is mostly also related to increasing of the pH of the system. Do you regulate Base and Acid in your process? If an alkaline or neutral E.coli Protease is responsible for deformation and autolysis,