Week 2 Blended Learning Flashcards
Metabolism
enzyme catalyzed reactions of a cell (primary common in most organisms and secondary for some microorganisms)
Catabolism
Energy generating metabolism, breaking large molecules into smaller ones
-Energy released as ATP
Anabolism
energy utilizing metabolism in biosynthesis of cellular components; building larger molecules
-Energy required as ATP
Products of primary metabolism
alcohols, amino acids, organic acids, nucleotides, enzymes, and microbial cells (biomass)
Products of secondary metabolism
alkaloids, antibiotics, toxins, pigments
What phase are secondary metabolites produced?
Stationary phase
What phase are primary metabolites produced?
Exponential phase
Fermentation
Is the process of deriving energy from the oxidation of organic compounds, such as carbohydrates, using an electron acceptor, which is usually an organic compound
How does the reaction of fermentation differ?
According to the sugar being used and the product produced
What is a product that can be produced by anaerobic fermentation?
Ethanol
What is a product that can be produced by aerobic fermentation?
Biomass
Inoculum
Starter cultures, for example it can wake yeast up from lag phase
Propagation
The culture organism is taken through several propagation stages in order to generate a sufficient quantity of inoculum.
Pilot-scale
Pilot- scale and many production vessels are normally made of stainless steel with polished internal surfaces. For pilot-scale and industrial fermenters more rigorous sterilization is necessary, involving increased sterilization time and/or higher temperature.
Fermentation media
-Depend on: Inoculum, Propagation Step, Pilot-scale fermentation, and Main product fermentation and on the objective of the process whether we want primary or secondary metabolites.
Chemotrophic microorganisms
Oxidate organic and inorganic compounds
Phototrophic microorganisms
Use light
Autotrophic microorganisms
Use CO2 as sole source of Carbon (inorganic)
Heterotrophic microorganisms
Use reduced organic molecules such as sugars, lipids, organic acids
Macronutrients
-Include C, O2, H2, and N2.
-C autotrophs from CO2, heterotrophs from sugars 10-20 g/liter
-C used for biosynthesis of higher organic compounds and as energy source
-O2, H2 from water
-N2 for proteins and nucleic acids from ammonium salts, also nitrates, amino acids, urea; concentrations 1-2 g/liter
Minor elements
-Include P, S, Ca, Fe, K, Mg
-Phosphate ions often as a pH buffer
-P used for synthesis of nucleic acid, involved in energy transduction ATP and NADP
-S supplied as inorganic sulphate or sulphide salt 20-30 mg/liter, S for production of some amino acids cystine and methionine and for some vitamins
-Ca, Fe, K, Mg 10-20 mg/l required for specific enzyme activities
Trace elements
-Include Co, Cu, Mn, Mo, Ni, Se, Zn
-0.1-1 mg/liter for enzymes normally sufficient quantities in water
Hypertonic solution
-A lot of solute outside the cell and cell has a lot of water. Solute outside of cell wants water, water is pulled out and cell is shrunk
Hypotonic solution
-Low concentration of solute outside of the cell, cell wants water inside. Causes it to burst
Isotonic solution
-Perfect conditions, in equilibrium
Passive diffusion
-Does not require carriers, or energy refers to hydrophobic substances soluble in lipids, material can enter through phospholipid membrane, no direct input of energy required, rate of uptake depends on magnitude of concentration gradient across the membrane
Facilitated diffusion
-Uses carrier proteins in cell membrane, no energy required. Mechanisms driven by concentration gradient across membrane, continuous process because intracellular concentration does not increase (immediate metabolism upon entry), transports sugars and amino acids, applies to more hydrophilic substances
Active transport
-Allows accumulation of materials against a concentration gradient (up to 1000 higher concentration greater than external concentration) requires energy by ATP or proton gradients. Transport of sugars and amino acids
How much substrate added in fermentation process depends on?
1.Initial step in media formulation is to look at process stoichiometry for growth and product formation ex. C6H1206—> 2CH3CH2OH + 2CO2 + 2ATP
- Consideration of input of carbon & nitrogen sources, minerals and oxygen, and their conversion to biomass, metabolic products, CO2, H2O and heat
- Calculating minimum quantity of each element required to produce certain quantity of biomass of metabolite (product)
- Approximate formula of microbial cells is C4H7O2N which is on basis of dry weight is 48% C 7% H, 32% O, 14% N
Knowing this elemental composition of microbes used in the process allows for further formulation refinement
- Often media are fed continuously or intermittently into the reactor to avoid repression of product formation. (if one of the components delivered to the reactor is consumed too fast, then if not delivered on continuous basis, can become a limiting factor in the growth and product formation)
- Environmental conditions also are important in the process
But THE KEY FACTOR IS CONVERSION TO BIOMASS
Industrial scale
Uses cost effective substrates derived from natural or animal material, by products of other industries
Factors affecting the choice of raw materials:
– Cost and availability
– Ease of handling (solid/liquid, transport, storage)
– Sterilization requirements
– Formulation, mixing, viscosity
– Impurities
– Health and safety
– Concentration of target product, its rate of formation
Biomass yield coefficient is defined as?
Ycarbon (g/g) = biomass produced (g) DIVIDED BY carbon substrate utilized (g
If you put 180 grams of glucose into bioreactor will you get 90 grams of ethanol?
-If you put 180 grams of glucose into bioreactor you won’t get 92 grams of ethanol because it’s not efficient
Industrial Carbon sources
Include: Molasses, Malt extract, starch and dextrins, sulphite waste liquor, cellulose, whey, alkanes and alcohols, fats and oils,
Molasses
-Byproduct of sugar production 50-60% sugars, some vitamins and nitrogen
Malt extract
Aqueous extract of malted barley concentrated to syrups 90% carbohydrates, vitamins, nitrogen, proteins
Starch and dextrins
-Polysaccharides, enzyme amylase required to break down polysaccharides
Sulphite waste liquor
-Waste liquor from trees 2-3% sugars, low pH due to SO2, requires processing to increase pH
Cellulose
Used in solid-substrate fermentors
Whey
Aqueous byproduct of dairy industry, contains lactose that is evaporated due to high costs of transportation and storage
Alkanes and alcohols
expensive due to rising prices of crude oil
Fats and oils
From cottonseed, olive, palm, soya carbon sources especially in antibiotic production
Nitrogen & Phosphate sources
-Can be either organic or inorganic in nature; inorganic would include ammonia salts; organic would include amino acids, proteins and ureas. Typical sources include:
Corn steep liquor, yeast extracts, peptones, soya bean meal
Corn steep liquor
-Byproduct of starch extraction from maize ~4% nitrogen, vitamins, minerals
Yeast extracts
-From waste beaker’s or brewer’s yeasts; yeasts cell hydrolysis by autolysis using endogenous enzymes at 50/75 C
Peptones
-Prepared by acid or enzyme hydrolysis of high protein materials (meat, gelatine, keratin, peanuts, cottonseeds)
Soya bean meal
In antibiotic fermentation due to slow metabolism
Water
needs to be of consistent composition with few minerals that contribute to hardness and little or no iron and chlorine.
Minerals & Vitamins
like humans, microorganisms require trace amounts of vitamins and minerals; some bacteria can actually synthesize vitamins but most need for them to be added. Vitamins and minerals ranging from amino acids to zinc are either added, or in the case of trace minerals, can be found in the water supply.
Inducers & Inhibitors
Those reagents that will either promote the growth of one metabolites or discourage the growth of another metabolite must be added to the media
Why do we need homogenous condition in the reactor?
If we don’t have same homogenous conditions in reactor, the rate of reactions might not be same, microbes might not be on same growth phase, will not make good quality products
Oxygen
for aerobic fermentation processes, oxygen is typically diffused into the media; for industrial applications, the source of the oxygen is air (as opposed to pure oxygen). The air is typically filter sterilized prior to injection into the media.
Antifoams
foaming during fermentation is largely due to media proteins becoming attached to the air-broth interface where they denaturate. Antifoams are physical and chemical that can suppress foam, don’t want to add too much can affect physiological conditions of microbes, little bit so it doesn’t affect too much of biochemistry of microbe
The problems of foaming include?
blockage of filters (loss of aseptic conditions and decrease in reactor throughput
Solution:
*Modification of medium composition
*Mechanical foam breakers *Chemical antifoams
What is the rate-limiting step?
Transport through the cell membrane
Adoption of media
Depends on scale of fermentation since it can add up to 80% of the process cost
Typical components of the media are?
Carbon sources, nitrogen source, phosphate source, sulfur, water, vitamins and minerals, oxygen, inducers/inhibitors, and antifoam agents
