Questions related to Bioprocess Engineering
I would like to produce gel filament of cell entrapped in polymer solution. But when I mix the suspension with the polymer solution, a pre-gel is formed and air bubbles are also entrapped in the mixture. I've already tried to removed the air bubbles by vacuuming but it takes very long time and isn't good for cell viability. Any idea how to remove the air bubbles without causing cell damaging?
I am working with RNA switches for tuning few genes for production of metabolites in Lactococcus. I have observed recombination events in my plasmids when I culture the respective strains for 24hours in a bioreactor. I am hypothesizing that the high cell density (almost 10 OD after a 24 hours bioreactor culture) causes recombination in between the switch-trigger pair sequences in the plasmids. I have verified this after sequencing them.
The reason could be that these switch-trigger sequences form very strong secondary structures and have reverse complementarity to each other, and thus recombine and omit out the sequences in between.
Now these switches are essential to my work. So I can not leave them.
Can you recommend me regarding what genes I can knock out in Lactococcus lactis for preventing these recombinations?
Hello, I am currently doing an assignment that focuses on designing CSTR. I am currently trying to figure out how to choose an agitator and its specifications such as the material used, type of impeller, speed of rotation, direction of rotation (if it affects the reaction) etc.
Below are the specification of the process:
Approximate volume: 60 L (Lab size reactor)
Process: Transesterification of Glycerol and Dimethyl Carbonate to produce Glycerol Carbonate (All Liquid) + Methanol as side product (gas)
Catalyst: CaO (solid)
Reaction temperature: 75 degree C
Reaction duration: 90 minutes
I would be truly grateful if anyone would share useful info, equations or anything that can help me in this. Thank you in advance and good day. :)
If we consider, for example, heterologous insulin biosynthesis in E. coli, we often find that a strategy based on synthesizing the target protein by expression plasmids has simply been adopted. But wouldn't that be a problem in terms of plasmid stability during continuous production on an industrial scale? Shouldn't such operations be performed with modifications at the chromosome level? There are definitely different nuances in other hormones, enzymes and proteins, thus I would appreciate it if you could explain by giving some examples.
Thanks in advance..
My current research is in the carbon flux distribution of L. rhamnosus in a biofilm reactor and I am struggling to find research pertaining to the continuous metabolic analysis in literature. Any help would be highly appreciated.
I am working to find a bioactive compound from a bacterial source which can show antifungal activity. So I have established the bacterial culture in a synthetic medium. What we found that the enzyme/proteinous compound is mainly extracellular in nature. Now I want to go for isolation, extraction and purification of the compound from the liquid culture of bacteria at laboratory scale. So I am asking to share your knowledge about the sort of suitable methods which will be helpful for getting the desired compound.
I am conducting a reaction with a highly viscous chemical, which is the reactant as well as the solvent, with the other reactant being less viscous and immiscible. I was able to achieve the mixing in a 2L flask by vigorous stirring using magnetic bead, which facilitated the mixing as well as the reaction. Reaction temperature is 120 deg C.
However, moving to a 10L vessel (glass, round bttom, 4 neck) with an overhead stirrer, there are issues with the mixing of the two chemicals, as the two reactants remain immiscible. Button stirrer with a PTFE blade was used.
What kind of agitator/impeller would be best for use in this condition?
As my aim is to study the anti-fungal activity by the bacteria, Is there any expertise member who can explain how to know a bio-active compound(may be protein, enzyme or other molecules) isolated from a bacteria is extracellular or intracellular in nature ?
The literature search could not helped me to find out the appropriate solution for this particular microorganism so I want to go for various experimental methods. So is there any proper step by step procedure for better confirmatory tests ????
I am struggling to calculate the columbic efficiency for acetate and glucose used as substrate in batch mode double chamber MFC. i haven't find a single paper for batch mode which had used formula for columbic efficiency with all those constants and other parameters units .
Should I add some preservatives or other chemicals to this solution?
What is the correct temperature to store this stock?
How long can it be stored in these conditions?
I'm producing lactic acid via anaerobic fermentation. I'm going to the equations in Michael L. Shuler Textbook "Bioprocess Engineering." He stated that there are two types of substrate inhibition for bacteria: competitive and noncompetitive. I need to figure out which one I have and how to find Ki, which he does not explain how to do in the textbook.
I converted salmon oil into FAME using lipase. I used BSFTA and tetrahydrofuran to derivatize the sample and injected in GC for separation and quanitification. I now have peak area for individual fatty acid methyl esters. Now how to calculate the FAME conversion yield?
For example: researchers say that they got 75% biodiesel yield at 1:3 oil:methanol molar ratio after 24 h of reaction time. I would also like to calculate in that manner. Some of the formulas are confusing and doesn't make any sense. Can someone help me out?
i have found the method for Electroporation of C. necator.
one of the steps says:-
The cells were then harvested, washed twice with 50 mL cold H2O, and concentrated in H2O to a final optical density of 25.
May i know how to do achieve the final OD of 25?
I'm using 1 g of bagasse for my solid state fermentation. How to calculate the pigment yield obtained and express them as g/kg dry weight?
In a continuous system using immobilized Saccharomyces cerevisiae, how does one achieve steady-state since the rate of cells flowing out of the system will not be consistent given their trapped nature in the alginate matrix? Are there any papers that describe this scenario?
I am trying to determine the reducing sugar yield after enzymatic hydrolysis. If, after DNS, the reducing sugar concentration is 115 g/L, what is the yield?
1 g of feedstock was added to 10 ml buffer for the enzymatic hydrolysis section.
If I am correct, I am getting 1.15 g/g, which seems implausible?
Understanding algae responses to stress can help to improve our knowledge about algae adaptation strategies which can be used to engineer tolerant strains. Also, it can be used to manipulate culturing condition to yield the higher amount of secondary metabolites like carotenoid.
In most of the articles that I am reading it is not mentioned why is important understanding adaptation mechanisms. Are there any other applications other than what I stated?
I read an article saying that 66.07 g of NH4+ will be available in 1 litre of water if 1 mole of ammonium sulfate is introduced to water
But i presume that 36 g/lit of ammonium should be present but the above mentioned reference says that 66 g/lit. kindly clarify me
1mole of ammonium sulfate = 132 g/lit ( N= 14,H=1,S=32,O=16)
Ammonium sulfate when dissolved in aqueous solution produces two NH4+ ion i,e 2*18 = 36 gm.
Kindly elaborate on pros and cons of both, if possible.
I'm interested in understanding the differences in levels of recombinant protein produced, ease of production and ease of genetic manipulation.
It is known that nitrogen and phosphorous both are vital for the growth of cells, then why in limiting condition does it enhance PHA production?
In ABE fermentation by clostridia, does continuous immobilization culture solves problems associated with continuous fermentation using suspended cells.
- Mixture of acidogenesis and solventogenesis in continuous system
- Degeneration due to solvent toxicity
- Difficult to achieve steady state
What are the other problems rise for continuous system.
Is there any solution to get rid of precipitation or is there any salt which doesn't get precipitated when added with CMC (Carboxy Methyl Cellulose)?
recently i have studied articles about biodiesel wastewater. we are producing large amount of waste waster in water washing of biodiesel. we can reduced waste water by adding some percentage of distilled water 10 or 5 min before ending transesterification process as prewash.
Hello! We did a small biodigester at home, it had two units: a recipient with 0.25L and a another variable volume recipient for gas storage. The biodigester starts up with 1.5kg of food waste, 1 kg of cow manure and 5L of water. The system seems to be good during adaptation time (we planned 15d for this and then to operate it in semicontinuous mode), pH measurements every three days was nearly to 7. Neverthless, 9 days after the start up we have to burn the biogas the because the storage recipient was too small, but... it didn't burnt.
We have an hypothesis about what was bad in our design: the (inoculum/substrate ratio) was to small (0.6 aprox.) and for food waste the recommended ISR must be over 2 for preventing the inhibition (food waste are easily biodegradable matter)
We are not sure about adaptation time or if we can burnt the biogas daily, but in this case the pressure maybe won´t be for flow through the tube. Maybe we must change the design or we are doing something bad during the start up?
I need commercial grade Cellobiose dehydrogenase (CDH). Does anyone have the information about any company/organization/supplier who can supply commercial grade CDH?
Firstly, we tried preparing feather culture media 1 & 2 using NaCl 0.5g/L, KH2PO4 0.4g/L, K2HPO4 0.3g/L, feather 10g/L, pH 7.5 (Media 1) and Media 1 + NH4Cl 0.5g/L, MgCl2.6H2O 0.1gµl, yeast extract 0.1g/L.
We optimized the temperatures for both media to 40 and 50 Celsius, but did not get satisfactory results. Thanks.
Now I need to design a transfer function for my bioreactor. The controllable parameters pH, DO, Speed, Temperature available in the system. I need to control all the parameters.
Is it possible to add more parameters within a single transfer function?
If yes, Then how i control the parameters separately?
More over i have a plan to design a MRAC for that system.
My article's reviewer wants me to determine the pore size of the membrane by gas (liquid)/liquid method, but I don't know this method. What is it? How does it work? If I don't determine the pore size by this particular method, which method is the best replacement for it?
It is assumed that to be a two stage system, the HRT should be greater in the acidogenic reactor because the hydrolysis step is which required most time.
The ungassed power number (Np) of a single impeller is 5.2 and for the two impeller system the power number can be assumed to be twice that value. Power consumption of agitation is reduced when gas is introduced into the vessel. Np,g/Np can be assumed to be 0.7 if Flg≥0.01.
height (H) to tank diameter (T) ratio H/T = 2. The fully baffled reactor is agitated with two Rushton turbines with a diameter D = 0.4T. The actual production takes place in a 50 m3.
I am interested about to design differents reactors to treat wastewater so as knowing which calculus I must do.
Thanks for advance.
I have been using mason's trichrome kit by sigma, can acetic acid play an important role in staining? I leave the tissue in bouin's for overnight and then hematoxylin for half n hour and then phospho tungstic and phospho molybdic acid for 5 mins and then aniline blue for 5 mins followed by 0.1% acetic acid.please suggest me as to what can be my mistake.
I wanna make an alginate scaffold. I have a sigma batch of alginate. In some papers, alginate is purified before further use. I wanna know how much it is necessary to do the purification?
I am doing a biological methane potential test and want to determine the chemical oxygen demand of the substrate amended with maize straw before / after the fermentation. The standard method I am using is the macherey nagel nanocolor CSB 1500. However, this method is only accounting for the soluble, but not the solid phase. Does anyone know a reliable method to determine the total COD of such samples?
I am working on phytase production by a B. subtilis strain. We are going to scale up the production using a NBS BioFlo 310 Bioreactor. We are going to use NBS EX-2000 Gas Analyzer for measuring O2/CO2 from the bioreactor exhaust, but unfortunately, we are having difficulty working with this equipment. Although, the air enters and exits from the machine, but its flow-meter doesn't work and the results aren't satisfactory! Also, how can I make sure that the machine is working properly?
Thank you in advance!
I am working on the reaction kinetics of biodiesel synthesis from rubber seed oil. I am proposing a pseudo-first order rate equation since the methanol will be in excess. I needed to test the proposed rate equation with available published data from literature
I am providing oxygen through sparging to my system (fermented broth) and it increases drastically the DO level in the broth. I am doing also agitation in the system for breaking of the large molecules of air bubbles, formed due to sparging, hence for proper mixing. But without sparging, the agitator system individually does not help in increasing the DO level in the broth.
I have checked it for lower to higher agitation speed maintaining the time of oxidation constant and no aeration,but still the DO is not increasing.
What does it mean?
Is that my limitation of agitator system?
I am protecting Dopamine with Acetyl groups and a protocol suggests running Argon through the solution to remove the HBr, which in the reaction is a 33% HBr solution. The link to the patent is here..
Im also wondering if I could replace the HBr with Acetic Acid, and if that will do the same job. That way I can evaporate the Acetic Acid through reduced pressure.
Anyone tried this before?
We are interested to use the Aber Futura Biomass probe (Dielectric spectroscopy) to measure the capacitance data of E.Coli and also scanning data of E.coli cell parameters (Cole-Cole alpha,Cell Diameter,Biovolume, Conductivity etc...). We are using bacterial mode(Default: 1.1MHz) with Polarisation OFF but we couldn't able to measure the capacitance data using default mode. Our offline data suggested that cells are growing well. Anyone can help us to solve this issue.
i have chitosan:polyethelene oxide combination nanofiber is availabe in that i want to remove polyethelene oxide alone?
chitosan is non soluble in water & PEO is soluble in water but i have nanofiber how i will remove?
any method is available or give me some suggestion?
We are interested to use the Aber Futura Biomass probe to measure the capacitance data of E.Coli and also scanning data of E.coli cell parameters (Cole-Cole alpha,Cell Diameter,Biovolume, Conductivity etc...). We are using bacterial mode(Default: 1.1MHz) with Polarisation OFF but we couldn't able to measure the capacitance data using default mode. Our offline data suggested that cells are growing well. Anyone can help us to solve this issue.
i am currently fermenting pichia and I am having issues with contamination. A red film keeps appearing in my solution after i inoculate it. instead of going acidic overtime the solution becomes basic. I have made new seed stocks which were grown in zeocion. Using the new seed stocks still leads to contamination.
I want to understand how much % of the water soluble extractives in switchgrass or corn stover is sugar which can be fermented or further utilised.
I would like to know the investment needed into a single-use process 2,000 liter monoclonal antibody facility, incl. labs, warehouse, offices etc. ?
what are the typical operating costs, especially HVAC ?
I like to study the barotolerance of few bacterial strains by applying high pressure. In the Bioreactor pneumatic pressure is applied. Can anyone suggest me high pressure resistive materials to inoculate cultures and incubate in the reactor? Similar studies has used sterile plastic bags, hungate tubes, blood pouches were they have applied hydraulic pressure. The material should withstand high pneumatic pressure.
I have tried to increase molecular weight of poly lactic acid of lower molecular weight by chain extension with di dissociates . It give me weight average molecular weight of 200000 Da. I would like to know does there is any other method to get ultra high molecular weight PLA.
When I use diluted seed oil with ethanol to react with DPPH in ethanol, I found that it couldn't dissolve it well and could see some precipitate that interferes with the measuring of absorbance. How can I solve this problem?
I am currently conducting a research into fungal enzymes involved in glycosyl hydrolysis. I am to select one of three organisms for enzymes production. The activity of the enzyme produced by the best of these three organisms is twice the second best and three times the least. However, when I used the same enzyme units (30FPU) for the three organism in a target hydrolysis, enzymes from the other two organisms (those with lower activities) had higher sugar yields (10% total sugar yield more than the best organism). Of course, I thought that the other two organisms might posses some other complementary enzymes which act in synergy to produce a higher sugar yield but I am concerned that they however require a higher volume of crude enzymes or some expensive enzyme concentration mechanisms that will rather make the hydrolytic process non cost effective. I urgently need a decisive guide about this.
I have been quantifying PHA produced by the microbes via crotonic acid assay. I had centrifuged 15 ml of medium to obtain a considerable amount of biomass , and I had treated the biomass alone with acetone , methanol and water to remove the cell debris and then I had dissoved the left out pellet in chloroform and boiled it at around 90 degrees and after which 20 microlitre of the chloroform extract was used for crotonic acid analysis by standard protocol.
When I compare the spectral readings with the standard graph and quantify I get a few micrograms in 20 microlitre and when I back calculate there is only a few micrograms in a liter of fermentation medium.
where as when I used thermogravimetric analysis of PHA in biomass I obtain micrograms of PHA / micrograms of biomass. can someone help me out with the back calculation.
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.
If we tend to consider optimization of the degree of freedom and maximal information of a chemical reacting system to be obtained, how and what can we conduct?
the pattern of consumption of amino acid is depend on yeast strain.
but is there any one knows the availability of oxygen also cause to consumed more amino acid or not?
i have a pichia pastoris clones (3) with my gene of interest which was confirmed by PCR and sequencing. My protein of interest is extracellular protein and when i am trying to express the protein with standard protocol as mentioned in the invitrogen pichia pastoris manual. After 96hrs of induction phase with methanol i am unable to see my protein on SDS-PAGE either by loading supernatant directly or after concentrating..what could be the possible reason for this?
After several trials I am unable to maintain DO during fermentation; increase of gas supply, addition of oxygen is not working as it increases pressure also. RPM increase is not a solution for filamentous fungi that too when the process have to be replicated at industrial level. I would like to know suitable oxygen vectors if anybody can suggest and kind of experience one can share.
In my gc ms experiment I have got long chain monomers c15 to c19 while using linoleic acid as a carbon source in pseudomonas putida .Can p.putida capable synthesize long chain polymers?
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
I am trying to determine accurate ethanol yields on glucose of different yeast strains in batch aerobic fermentations using bioreactors. I am using media containing around 240 g/L sugars which, using S. cerevisiae in anaerobic conditions, could result in up to 13-14% ethanol (v/v).
I need to extract this compounds from my biodiesel sample in order to characterize them in HPLC tests. Any suggestions are welcome.
The rapid decrement in C/N ratio indicated active microbial degradation on the carbon source.
As I know, lactose serves as both carbon source and inducer. Thus it is consumed as a substrate, which may decrease the capability as inducer. The good part is that excessive lactose is not harmful to cell growth. In contrast, IPTG serves only as inducer and cannot be metabolized, so it is more stable. However, I found that excessive IPTG will be "toxic" to cells and the cells aggregate and finally will be lysed if incubated further. Why is it like this?
In terms of protein or metabolite production:
How will the transcription change when induced with lactose instead of IPTG? Will it drop significantly over time?
Is it better to induce with excessive lactose than moderate IPTG?
In a bioreactor, is it useful to induce continuously but with relatively low concentration of IPTG?
Some more general questions:
Is it useful to optimize the amount of inducer dosage?
Is it better to induce at early log phase than at mid log phase?
I am looking for a protocol for ion pair reverse phase hplc using Luna C18(2) column for estimation of intracellular nucleotide precursors (e.g. UTP, UDP, ATP, AMP etc.).
The major concern is that the salt concentration in the protocol should be as low as possible.
I did the experiment for the determination of reducing power by oyaizu 1986 method and found absorbance values but how to do the calculation to determine reducing power or the extract? do we have any formula? Or the absorbance values corresponds to reducing power? What unit should I use?
I am going to check the activity of an enzyme on a substrate which gives acetic acid as one of the products.
The problem is that the container of 20l which I will be using cannot be autoclaved so I will be using 500 ml conical flasks. However, that will require a large number of flasks and it will take lot of time to do the autoclave. Is there an easier way to do this? My lab has a vertical autoclave and a horizontal autoclave.