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.
Questions related to Fermentation
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
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
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?
Do you think it is possible to make this thing? Please attach your answer with some sources if possible.
As PhD student specialized as food and industrial microbiology need to further research on bacteriocin and fermented food.
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?
How we should screen out the solid material left after 90 days of fermentation in making of garbage enzyme. Is there any standardized process.
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?
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.
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?
I'm looking for selective culture media for Akanthomyces muscarius.
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?
SSF is being performed for the production of bioactive metabolites.
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.
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
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?
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.
This could involve manipulating media composition, fermentation conditions (pH, temperature, oxygen), or even strain engineering approaches.
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
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?
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.


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?
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.
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?
The experiment is to enhance high yield of bioactive compound . combination with agrowaste and bacteria
Can a fermentation system experience higher OUR values than OTR. How does this affect the process parameters.
please cite some reference papers also if possible which clears this concept
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?
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?
i am doing dark fermentation with thermophilic bacteria and nanoparticle as supplementation.
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!
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.
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.
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.
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!
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.
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?
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?
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
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!
Is a lactic acid bacteria strain sourced from plant sources is more suitable for fermentation of plant proteins compared with a dairy sourced strain?
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
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!
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:
- 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
- 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 –
- Bacterial Lipopolysaccharides and Neuron Toxicity in Neurodegenerative Diseases. Neurology Research and Surgery. 2018; 1(1): 1-3.
- Overnutrition Determines LPS Regulation of Mycotoxin Induced Neurotoxicity in Neurodegenerative Diseases. Int J Mol Sci.2015;16(12): 29554–29573.
- Functional Foods and Active molecules with relevance to Health and Chronic disease: Editorial. Functional Foods in Health and Disease 2017; 7(10): 833-836.
- Food Quality and Advances in Pharmacological Management Prevent Mitochondrial Apoptosis and Epilepsy Induced Stroke. Research and Reveiws: Neuroscience. 2018;2:7-9.
- Food quality induces a miscible disease with relevance to Alzheimer’s disease and Neurological diseases. J Food Research, vol. 5, pp.45-52, 2016.
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
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
If the media is placed in a shaker during the fermentation time, ethanol production increase or decreae??
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.
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.
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.
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.
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?
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
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.
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.
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
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
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
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.
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
Why the productivity of Exponential Fed Batch Fermentation is Lower than that of linear Fed Batch Fermentation ?
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.
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.
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?
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
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.
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
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.
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?
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?
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?
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.
The tested species are growen in broth and they incubated for fermentation optimicaly
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?