Questions related to Microbial Fermentation
I am doing normal batch fermentation calculations (for the first time) and am confused about how to carry out some of the calculations. Specifically, I would like to know:
- The equation for substrate uptake rate (g/L/h)
- The equation for specific substrate uptake rate (g/g/h)
- Whether it makes sense to do these calculations (in addition to yield and growth rate) for the overall batch or between each of the sample points
The calculation of specific/substrate uptake rate seems pretty easy from a dimensional analysis stand point. However, I am not sure whether to use the specific growth rate, μ (1/h), to account for the time dimension in calculating specific/substrate uptake rate or to use Δt instead (h). Each of them leads to different results it seems. I have seen answers that use either of them and now I am confused.
Any help would be highly appreciated.
How to Identify and Estimate the Lactic acid from the Microbial fermented broth other than HPLC using Simple methods?
if possible such as
1. Calorimetric or Spectroscopic methods
and much more
Can someone tell me how to increase the shelf life of pickles to 6 months to 1 year..?
Below are details
- Should not have artificial preservatives
- Packaging should be glass bottles
- Quality of the product should not deteriorate (Taste and authenticity should remain same)
- Cannot use Retort because it is deteriorating the taste of the product.
I want to analyse some fermentation samples for detection of Butanol, Ethanol, Acetone, Butyric acid, Acetic acid etc. using a TR-FAME (fatty acid methyl esters) column and GC-FID method. In this column no water based samples should be introduced as it may harm the column matrix. Commercially purchased analytical grade Acetone and Butanol gave fine peaks when analysed in this column. In this situation what is the procedure for preparing non-aqueous samples from the aqueous fermentation broth that will contain the produced acids and solvents to be analysed in GC?
I have a protein of interest that is expressing in Pichia. It is expressing well in the shaker flask, but when I apply the same expression methodology but now in a bioreactor I get minimal expression.
Any logical reason for this? Is the density inhibiting the expression somehow. I would think that that more cell mass = more protein expression but could there be some kind of quorum inhibition by pichia?
There is room for more biomass production in the bioreactor, but I keep the feeding rate such that it does not go to the maximal limit to allow for protein synthesis.
Please researcher shear few research paper with Fermentation optimization techniques. Both In Silico such as predictive modeling and In Vitro such as substrate standardization.
I'm working with Bioflavour producing Microorganism thus need this help!!
An oil rich substrate is not producing the expected result of reduction in ANFs after microbial fermentation. Could it mean that defatting or solvent extraction using hexane needs to be done first prior to solid state fermentation? Pls kindly add a published reference
What affects the protein quantity from an inclusion body during microbial fermentation? Are there any available resources to quantify the exact protein yield expected from inclusion bodies in E.coli?
I want to use MES buffer in my microbial fermentation media, The content of buffer will be also used by microbes or it is not usable?
It will needs to care about the buffer contents in media also or it cannot affect the media composition?
is there any counting chamber with a grid so small to allow for bacteria counting with a 100x immersion objective? Burker and similars have 0,0025 sq. mm grid which can only be entirely visualized with a 40x objective. However, some cocci are hard to spot with 40x magnification, I need to go with a 100x.
Thank you all in advance
Pichia pastoris is fermented for recombination protein.
I set fermentation condition that DO value 50%.
I want reducing the pure oxygen rate, but maintain or increase DO value.
I intend to evaluate the influence of the parameters inoculum ratio / must, fermentation time and temperature on the wine parameters, mainly ethanol. For this I need a same amount of sugars in the must to perform the experiments.
Could I do this by monitoring only soluble solids content (sucrose) in a refractometer, and occasionally adjusting with sugar, or would it be more convenient to monitor glucose, fructose and sucrose and try to fix values of these sugars for each sample?
can anybody help me?
It would be helpful if I get an answer for calculating the exact amount of a oxidized compound after the reaction. For example if 5 mg of substance is mixed with an electrolyte. I need to know how much amount of substance oxidized during different cycles and different scan rate. Is there any protocol or methodology to find the quantity rather than getting the current values.
I need to use 6M sulphuric acid as an electrolyte solution for cyclic voltammetry studies. I know 0.5 M or 1 M sulphuric acid can be used. What will happen if higher concentration of sulphuric acid used. Also during the course of reaction, will it affect the counter platinum electrode or reference silver electrode?please clarify the doubt or send me some related reference papers
I would like to study the effects of human intestinal bacterial on flavonoid, and some one suggested I use sheep's gut as the animal experimental model. Any one have some experiences about this, for example what's kind of medium do you use? Thanks a lot for your help.
I am trying to isolate fungal mutants with enhanced xylanase activity. What is the most appropriate inducer for the same which can be part of the medium.
Could you suggest a method to give the effect of pressure on microbial growth? Kindly give the procedure or kindly give some reference article to follow?
Crab tree positive effect of Ecoli leads to acetate accumulation. Apart from engineering of Ecoli strains, what are the feeding strategies and process control optimization can be done to avoid acetate (<1g/l)
I want to produce a Bacteria that belongs to Bacillus species at large scale so can i use LB medium or is there any other suitable medium that can be used with ease. I need your valuable suggestions. Thanks
Hi everyone, I have a question regarding oxygen transfer in stirred tank bioreactor. I'm currently doing research regarding rocking-motion bag bioreactors. As I did my literature review, I noticed that stirred tank bioreactor is more widely used for microbial fermentation compared to rocking-motion bioreactor.
Many attribute such common application to its superior oxygen transfer performance which is critical for aerobic microbes cultivation. May I ask usually what kind of transfer coefficient (kLa) could a stirred tank achieve in laboratory scale, say 10-20 L? And if possible, can anyone tell me what is common oxygen transfer coefficient (kLa) in industrial scale, say 1000-2000 L? Thanks
I have put up a fermentation experiment using yeast cultures. I am using synthetic sugars for the process and for detection of bioethanol produced at the end of the process, I would like to prefer Gas Chromatography. But DNS test of my culture supernatants suggest that there is some sugar left in them. Can I use these supernatants directly for GC analysis or do I need to pretreat them to precipitate out the sugars?
During my storage study with a particular type of fermented food product samples, the count of lactic acid bacteria was found to increase with storage time, which would reduce the proliferation of pathogen. However at the same time in one of the samples, after six weeks of storage Staphylococcus spp was observed to be growing and reached to a maximum at the end of storage time. What might be the possible reason?
I grew C.butyricum in flask RCM medium, and it grew up to OD620=2 in 24h.
I transferred 100ml culture into 2L glycerol medium containing no yeast extract (start OD=0.2 after innoculation), and it can grow up to OD620=0.7.
However, the problem is that glycerol concentration was not decreased at all for several days (pH6.5, 37C, 250rpm).
I guess they grew using RCM medium (100ml) and dont use glycerol.
According to several papers, they can consume glycerol rapidly.
What do you think about this problem? and what can I do?
I am performing co-fermentation experiment with glucose and xylose and to determine the residual sugar concentration I generally prefer HPLC method but HPLC is not in work for a few days. Can anyone suggest me a way to estimate glucose and xylose concentration separately because I want to see how much xylose has been consumed ?
One day I visited the scale up section of a fermentation plant. They were talking about the DOI. What I think is productivity may increase to some extent but there may be chances of oxygen toxicity. Is there any chances of oxygen toxicity?
I'm currently conducting research on the production of xylanase, pectinase and protease via solid state fermentation. The crude enzyme I harvested from each set of SSF is my primary source of each enzyme I mentioned earlier.
From my literature review it is okay to use sodium acetate buffer for the extraction of xylanase and pectinase. How about protease? does sodium acetate buffer suitable for the leaching out of protease from the SSF?
is it possible to perform a mixed culture between Pseudomonas aeruginosa or Acinetobacter baumannii and a yeast? how it is possible to monitor mixed culture and to shift the favorable conditions to a yeast without causing the death for Pseudomonas aeruginosa in the same culture?
During recombinant protein expression (RPE) cellular/metabolic stress is developed inside E.coli, which then depresses the RPE over time.
Over the past few decades, several genes have been identified which can be used as a biomarker or probe to monitor this stress e.g. ppGpp, whose expression level increases with increased oxidative stress developed inside cell. Like this there are various stresses e.g. heat stress, osmotic stress etc. which are well correlated with the RPE.
I am trying to catalogue all those genes which can be used to monitor different type of stresses developed during RPE in E.coli.
Your valuable suggestions, ideas or Paper references will be well appreciated.
The innoculum sizes for starter culture (controlled fermentation) seem to vary. How is it dependent on the organism being used or is there a minimum quantity that will ensure that the desired organism is responsible for most metabolic transformations.
Solaris Biotechnology srl is a sme located in Porto Mantovano (Italy), available for collaboration in EU research projects (i.e. development of microbial fermentation processes at lab and industrial scale, downstream processes, photobioreactors development for algae cultivation).
Cell Viability is critical for achieving high cell density and produce recombinant proteins in Ecoli/Pichia/Chinese Hamster Ovary cells. I appreciate any useful input.
When a microaerophilic microbe is used for the production of PHA and glycerol is used as the sole carbon source what would be the risk of contamination in doing an open batch fermentation process, Mineral medium is the base media where in trace element solution is added . can there be contamination with the addition of trace elements
I just tried an unsterile fermentation mode and I could produce PHA but the production is comparatively very less than that of sterile fermentation conditions.
Solaris Biotechnology srl is a sme located in Porto Mantovano (Italy), available for collaboration in EU research projects (i.e. development of microbial fermentation processes at lab and industrial scale and downstream processes).
I would like to produce lactic acid via the fermentation route, mostly simultaneous saccharification and fermentation (SSF).
I am looking bacterial strain which will give the highest lactic acid yield at optimal SSF conditions.
Buy from ATCC?
Who is willing to share his/her lactic acid bacteria strain?
We may set up a research collaboration.
Bio-transformations of natural and synthetic compounds are performed by using a large range of bacteria and fungi.
Can I use a magnetic stirrer for water insoluble compounds; or should I use emulsifying agents for this purpose?
it always forms two layers ,due to polar and non polar properties, so fatty acids are not properly transfer in to the medium ,some one would suggest me to solve the problem
A. niger can produce large number of organic acids. Certain time i would like A. niger to prduce Specific acid more. Example, if my interest is citric acid, then what parameter will help me to get more citric acid than other organic acid like gluconic acid, oxalic acid, etc.
(Under submerge Condition)
How can we estimate the acetic and formic acid content in a solution using a UV-Vis spectrophotometer? If anyone has the protocol, kindly provide it as some protocols I have found on the internet are not working. Thanks.
I'm seeking for a gene that can be used to differentiate between C. ljungdahlii, C. autoethanogenum and C. ragsdalei. As far as I know from whole genome sequencing data, they have identical 16S and 23S genes. ITS regions also vary within the multiple rRNA operons those cells have so it is not a good choice.
I checked complete genome sequences for autoethanogenum and ljungdahlii to find candidate genes to differentiate among them, but could not find acces to ragsdalei data apart from the 16S rRNA gene.
I'm also having a similar problem with C. carboxidivorans and C. scatologenes.
Any help will be welcome.
I am writing to ask about a problem that has been happened in cultivation of a microbial strain, lactobacillus Bulgaricus.
I used to culture this microorganism in a 10litere bioreactor and reach a certain optical density but after my previous working banks finished, I made another series of working bank from the same mother stock. These new working banks are not as efficient as my previous working bank. Although the inoculums which are prepared by culturing the working bank growth well as usual, the final optical density in bioreactor has decrease to a quarter. For finding the reason of the problem I repeated this procedure twice and the result was the same. Even using direct inoculums from another mother bank that had not been thawed before, could not solve this problem and the final optical density was not as high as before. The fermentation conditions and medium ingredients were the same throughout all the experiments. I am looking for the reason of this problem and want to find out what was happened to these cells.
I want to study the effect of temperature on growth of pseudomonas aeruginosa in solid state fermentation, so I want to determine the growth of biomass at the end of fermentation period at each temperature. The production of CO2, during the fermentation, is not enough to be sensed by sensor. How can I determine the biomass?
The bio reactor is a vessel like a Graduated cylinder with volume 50 cc. I put an air distributor at the bottom of the Graduated cylinder and an effluent on the head that is connected to the sensor of CO2. By the way, because of temperature gradient that occur in greater bio reactors, I can not use greater one to reach much CO2 Concentration.
I put about 10 grams mixture of Corn bran+Corn germ in the bioreactor,
this substrate mixture have protein and it is not possible to use protein test to estimate biomass.
who knows what else substrates can I use that is tested before for pseudomonas aeruginosa to produce rhamnolipid?
We use caustic soda in a fermentation process for pH control and there is some question to its sterilizing properties.
I need the procedure to standardize it in the laboratory for practice.
Microorganisms involve usually in spontaneous fermentation belong mainly lactic acid bacteria and yeast. Production of African traditional cereal alcoholic beverages need two obligatory spontaneous fermentations steps: a lactic acid fermentation which is carried out by a complex population of environmental microorganisms and an alcoholic fermentation.
In bacterial physiology, lag phase is defined as the phase which is necessary for adaption of cells to new environment. During this phase the bacteria grow and the size increases; but the population density is almost constant.
In textbook, it is recommended to have at least 5% of inoculum to decrease the lag phase.
Now, my question is:
How the increase of inoculum quantity can decrease the time needed for adaption and growth of each bacterial cells?
For calculation of the generations in broth medium, I determine the initial number of bacteria and then the final number of them in a given time. Afterwards, by using the formula, I can determine the generations.
Now I would like to know the method to determine the number of generation in a solid culture medium.
Please let me know your opinions on which approach is better (pro and con), if one would like to investigate microbial populations (bacterial, and/or fungal if possible) in plant leaves fermentation processes over a time period (some months).
I am growing e.coli in fermenter with glucose in minimal media at pH 7.4 (50mM SPB). Technically, first D.O. should decrease (to nearly zero) due to cell growth, and then it should increase, due to optimum growth. But, in my case, D.O. is decreasing up to 6-7% and remaining unchanged till end. Although growth and other vital parameters are normal, pH is decreasing and O.D. at 600 is increasing properly. I can't understand what is happening?
Usually, detection of hydrogen after fermentation process is use GC, HPLC, gas meter, etc. Do you think is there any methods which can detect microbial community which can produce hydrogen only base on the using of medium?