Applications of fermentation (lec 5)

Applications of fermentation:

1. Microbial biomass

   1. Single cell protein

   2. Baker’s yeast in baking industry

   3. Microbial insecticides

2. Food production: vinegar

3. Metabolites production

4. Amino acids

   1. Glutamic acid

   2. Lysine

5. Organic acids

   1. Citric acid

   2. Lactic acid

6. Secondary metabolites production: antibiotics (penicillin)

7. 1. Biopolymers

      • Glycocalyx

      • Xanthan

   2. Biosurfactants

      • Rhamnolipids

8. Bioremediation

9. Biotransformation

10. Biofuels

11. Bioleaching

12. Immunological production

    1. Vaccine production

       • Polio inactivated vaccine

    2. Monoclonal antibody production

       1. Muromunab-CD3

       2. Nivolumab

Ex. of single cell protein used as dietary supplements:

• Central Africa: Blue-green algae (cyanobacteria) human supplement “spirulina”

• BP: petroleum fraction + candida sp.= torpina animal feed

• ICI: methanol+ M. methylotropha bacteria= pruteen animal feed.

The m.o. used in production of Baker’s yeast is……………………………

Saccharomyces cerevisiae

Yeast is harvested by…………………..

centrifugation.

Give example of bacteria microbial insecticides:

Bacillus thuringiensis (Bt) dried spores + prototoxins that solubilize the protein in the alkaline digestive tract of insects.

Summarize vinegar production.

Step 1: Alcoholic fermentation

Sugars are fermented by yeast (Saccharomyces cerevisiae) into ethanol & CO2 (anerobic conditions)

Step 2: Acetic acid fermentation

Acetobacter bacteria oxidizes ethanol into acetic acid in an aerobic process.

Enzymes used in industry are mostly………………….

hydrolases.

Uses of microbial enzymes in industry:

• Production of nutritive sweeteners from starch

• Detergent industry (proteases & lipases)

• Textiles industry (a-amylases, cellulase, proteases)

• Leather bating (proteases)

• Medical uses (penicillinases, fungal dextranases, proteases)

Common enzyme immobilization techniques.

Give advantages, disadvantages and when to use immobilized cells over immobilized enzymes:

• Advantages:

  • Cost effective

  • Convenient

• Disadvantages:

  • Difficulty of substrate & production permeability

  • Byproducts may be formed

  • Lower yield

• When to use:

  • When a cost-effective method is needed

  • When reaction has many metabolic steps

  • When enzyme extraction is difficult

Applications of immobilized enzymes:

• Immobilized glucose oxidase in biosensors (glucose meters)

• Immobilized glucose isomerase for high-fructose corn syrup production

Therapeutic amino acids and their uses include:

• Glutamic acid production for neuropathic diseases

• Lysine production for wound healing

Limiting biotin in glutamic acid production causes:

• Increased permeability in bacterial cell wall to release the amino acid.

• Inhibits enzyme, so that a-ketoglutarate gets mostly converted to glutamic acid, not oxaloacetate.

Overproduction of lysine amino acid require…………………of C. glutamicum, so we get a defective………………..enzyme and no threonine.

Homoserine mutant

Homoserine dehydrogenase

In citric acid, solid state fermentation is done on…………………………….

rice bran on aluminum pans.

In citric acid submerged fermentation, highest yield is in………………..phase. pH should be lower than………………………….

accumulation

3.5

To increase yield of citric acid in submerged fermentation,……………or…………….can be added.

ethanol or methanol

………………………….gives higher-yield of lactic acid in continuous fermentation.

Cell immobilization

Citric acid fermentation is………………….while lactic acid fermentation is……………………………

aerobic

anaerobic

Most important components in fermentation media for penicillin production:

• The side-chain precursor, phenylacetic acid

• Sulfur compounds because penicillin has sulphur

Fermentation phases in penicillin production:

• First phase (trophophase) 30 hrs fungal growth

• Second phase (idiophase) 5-7 days; penicillin production

• Third phase: depleted C & N sources; production stops.

In penicillin production, why is it important to add sidechain precursor?

to avoid production of various natural penicillin mixtures which are difficult to separate.

In penicillin recovery, filtration is done by………………………. Extraction uses solvent…………………..and re-extraction needs ………………………..

Rotary vacuum filter

Butyl acetate

Aq. potassium buffer

Example of natural biopolymer:

glycocalyx on bacterial cell wall.

In the recovery of xanthan, precipitation is done by…………………………

alcohol.

Properties & applications of xanthan.

Properties:

• Viscous

• Thermally stable

• Pseudoplastic

Applications:

• Thickener in food

• Hydrogel in pharmaceutics

• Painting

• Enhanced oil recovery

Applications of rhamnolipids:

• Cleaning (eco-friendly detergent)

• Antimicrobial activity

• Enhanced oil recovery

In recovery/downstream processing of rhamnolipids, the end residue is………………….

honey-colored.

Microbes used in bioremediation:

genetically engineered Pseudomonas putida

Give examples of steroids biotransformation.

• Plant-derived diosgenin or animal-derived cholesterol—→ Progesterone—→ by fungus—→Cortisone.

• Cortisol—→ Corynebacterium simplex cells—→ prednisolone.