Midterm Flashcards
what are the three traditional workers in the fermentation industry?
Bacillus (extracellular enzymes, antibiotics, insecticides), Aspergillus (citric acid exoenzymes used in food industry
biotransformations), Saccharomyces (yeasts, bioethanol
potential for other fine & bulk chemicals)
Gram positive bacteria and gram negative bacteria
The gram positive bacteria secretes enzymes outside, but the gram negative bacteria may be periplasmic
What is exponential equation for microbial growth?
dx/dt = μx - αx where x = cell concentration (mg/mL) t = incubation time (h) μ = specific growth rate (h-1) α = specific rate of lysis or endogenous metabolism (h-1)
What happens in the microbial growth equation when μ»α?
td = ln2/μ
What happens in the deleterious and stationary stage?
Deceleration phases and stationary phase, does not mean that cell division is not happening, just means that the dividing is happening at the same rate as death rate
What are bacteria species grouped based on?
growth temperature range
Define amphibolic, anapleroic reaction
1.) when a biochemical reaction has both catabolism and anabolism. 2.) To replace intermediates in the TCA cycles as some TCA intermediate molecules are important in biosynthesis such as amino acids. This ensures that the TCA cycle can still resume. Example: PEP combined with CO2 makes oxaloacetate
What is the difference between primary and secondary metabolite?
Primary metabolite (often precursors ): produced as part of growth i,e ethanol from Saccharomyces cerevisiae Secondary metabolite: Produced near of in stationary phase. not required for cellular biosynthesis; have no direct role in energy metabolism. Presumably have some advantage in natural environment. Often are family of vey closely related compunds i.e Penicillium chrysogenum produces a suite of very similar antibiotics but Penicillin G in most amounts
Enzyme system subject to induction and repression. After enzyme is formed how are they regulated?
induction (small molecules - inducers i.e allolactose), bind to allosteric protein - conformational change leads disscaostes from operator and transcription starts. vs co-repressor (such as gaccumulation of amino acids) - same as above
isoenzymes, concerted and cumulative
What is an example of enzyme modification?
covalent modifications alter protein conformation and regulates enzymatic activity (inhibit or enhance)
I,e adenylation of glutamine synthetase (Adding AMP)
glutamine synthetase when high glutamine, there will be high AMP which binds to glutamine synthetase to inhibit activity
True or false: Prokaryotes are capable of endocytosis?
False - no membrane bound organelles
Biomass concentration at time “t” in batch culture equation?
Biomass at time t :Y =( x - X)/ (SR - s)
When s = 0: Y = (x - XR)/(SR)
x = cell concentration at time “t” XR = inoculum or initial cell concn Y = yield factor for limiting substrate (g biomass/g substrate consumed) s = substrate concn at time “t” SR = original concn in medium
Difference between turbidostat and chemostat in continuous system?
possible to run as turbidostat (μ = μmax); medium inflow controlled by culture turbidity (maintained constant)
possible to run as chemostat; where culture turbidity is controlled by one limiting nutrient in medium inflow, growth rate is controlled by rate at which new medium is introduced
In a homogeneously-mixed continuous reactor (i.e., CSTR) what is equation at steady state?
Steady-state where formation of new biomass in culture is balanced by loss of cells from culture, & specific growth rate (μ) is controlled by the dilution rate (D)
D = F/V (Note volume should be constant and therefore D is controlled by F)
V = the volume (m3)
F = flow rate (m3 per h)
True/False: once steady state is established at a given D, only a single value of “x” & of “s” is possible
True:
x (steady state biomass) is controlled by D and SR
x = Y [SR - KsD ]
μmax - D
s (stead state substrate conc) is controlled by D
s = KsD
μmax - D
What are the two main types of mixing behaviour?
Newtonian - the viscosity of the culture is independent of shear force
non-Newtonian (several classes) - the viscosity varies with shear forces
fungus-containing broths can alter in apparent viscosity during growth
increasing viscosity affects bubble retention, gas transfer
True/False: microbes capable of growing in minimal media generally grow much better in complex media
True
What are the 6 criteria to consider when choosing feedstock?
cost; ready availability of material
transportation costs
post-production waste disposal issues
uniformity in raw material quality, ability to standardize
chemical composition of medium, presence of relevant precursors
regulatory limitations (e.g., FDA filing)
growth & production requirements of microbes
Which type of feedstock would be suitable for high carb requirement and low N?
corn steep liquour (But have to neutralize) - by-product of starch production from corn; highly acidic (SO2 addition) → need to neutralize
Which type of feedstock would be suitable for high protein and carb?
Distillers soluble - by-product of distillation of alcohol from fermented grain
Which feedstock have precursor for forming penicillin?
corn steep liquour- penylethylamine
Molasses feedstock used for?
molasses: by-product of sugar industry
used in production of potable & industrial alcohol, acetone, citric acid, glycerol, yeast biomass
Define Respiration:
respiration: catabolic reactions producing ATP in which either organic or inorganic compounds are primary electron donors & organic or inorganic compounds are ultimate electron acceptors
Define fermentation in terms of catabolism
catabolic reactions producing ATP in which organic compounds serve as both primary electron donor & ultimate electron acceptor; & ATP is produced by substrate-level phosphorylation
Who invented the term Biotechnology? and fermentation biotechnology is what colour?
Karoly Ereky, white
What are some other definitions of fermentation?
any process involving the mass culture of microorganisms, either aerobic or anaerobic. fermentation involves the use of microorganisms to carry out enzyme-catalyzed transformations of organic matter.
Includes the production of alcoholic beverages
food spoilage
What was the key in glycerol production in ww1?
Bisulphite
How does Bisulphite lead to glycerol production?
Prevents acetaldehyde production, and there is a build up of NADH and a lack of NAD+ . to fix the redox imbalance, the cell diverts the carbon flow to produce NAD+ with end product is glycerol
Example of biotransformation to avoid deactivation of penicillin due to enzymatic hydrolysis of penicillin acylase ?
semi-synthetic penicillin
mass culture of fungus (P. chrysogenum) to produce PenG
mass culture of suitable bacterium to produce penicillin acylase
recover & purify enzyme → biotransformation protocols to produce semi-synthetic penicillins using 6-APA as “base” molecule
at pH 7.5-8.5: use enzyme to convert PenG to 6-APA
run reaction in reverse at acidic pH with suitable acyl donors present → produce semi-synthetic penicillins from 6-APA
Which compound is the core of penicillin production?
6-APA is the core of penicillins- used as the main starting block for the preparation of numerous semisynthetic penicillins.
