Fermentation

Question 1

What is the Fermentation Process

Answer 1

It is the generation of energy by the catabolism of organic compounds.

Question 2

Describe the Fermentation process

Answer 2

It is the generation of energy by the catabolism of organic compounds.
For example,
Catabolism of sugar is an oxidative process which results in the production of reduced pyridine nucleotides.
Under aerobic conditions, reoxidation of reduced pyridine nucleotide occur by Electron transfer by cytochrome system with oxygen as the terminal Electron acceptor.
Under anaerobic condition, reduced pyridine nucleotide oxidation is coupled with the reduction of an organic compound which become the subsequent product of the catabolic pathway.

Question 3

What are the major groups of commercially important fermentation.

Answer 3

1. Those that produce microbial cells/ biomass as the product.
2. Those that produce microbial enzymes.
3. Those that produce microbial metabolites
4. Those that produce recombinant products
5. Those that modify a compound that is added to the Fermentation- the transformation process.

Question 4

What are the two major process of Commercial production of microbial biomass

Answer 4

1. Production of yeast to be used in the baking industry
2. Production of microbial cells to be used as human food/animal feed.

Question 5

Give 5 examples of commercial application of enzymes with source and application

Answer 5

1. Amylase
   Source: Fungal
   Application: in baking and milling
   Reduction of dough viscosity
   Acceleration of fermentation
   Increase in loaf volume
   Improvement of crumb softness
2. Glucose
   Source: Bacterial
   Application: Manufacture of fructose syrups
3. Lactase
   Source: Yeast
   Application: Milk industry
   Production of whole milk
4. Pectinases
   Source: Fungal
   Application: fruit juice clarification
5. Proteases
   Source: Fungal
   Application: stabilisation of evaporated milk

Question 6

Define Trophophase

Answer 6

It is the phase in the active growth of culture in which primary metabolites are formed. They are produced equivalent to the log or exponential phase. These primary metabolites are either anabolites (products of biosynthesis) that are essential to the growth of the organism and include amino acids, nucleotides, proteins, Nucleic acids, lipids, carbohydrates or are either catabolism (products of catabolism) such as ethanol or lactic acid.
The synthesis of anabolic primary metabolites is met by modification of wild-type microorganisms that is achieved by recombinant DNA technology.

Question 7

Name 3 primary products of microbial metabolism

Answer 7

1. Ethanol from yeast is used as the active ingredients in alcoholic beverages or used as a motor-caf fuel when blended with petroleum.
2. Glutamic acid, a flavor enhancer
3. Lysine, a feed supplement

Question 8

Define idiophase

Answer 8

During deceleration and stationary phase, some microbial cultures syjthesize compounds which are not produced during the trophophase, these are called secondary compounds of metabolism. They may not have any obvious function in cell metabolism and the phase in which they are produced is equivalent to the stationary phase is known aa idiophase.

Question 9

What are some properties of secondary metabolites amd how they are produced

Answer 9

Secondary metabolism occur in continuous culture at low growth rates and is a property of slow- growing or nongrowing cells.
Compared to primary metabolites, wild-type microorganisms tend to produce only produce only low concentrations of secondary metabolites, their synthesis being controlled by induction, quorum sensing, growth rate, feedback systems ams catabolite repression, modulated by a range of effector molecules.
These secondary metabolites have antimicrobial activity, specific enzyme inhibitors, growth promoters and pharmacological properties.

Question 10

Examples of secondary products of microbial metabolism and their commercial significance

Answer 10

• Lovastatin, a cholesterol lowering agent
• Penicillin, cephalosporin, streptomyces: Antibiotics
• Cyclosporine A: Immunosuppressant
• Avermectins: Antiparasitic agents

Question 11

Define heterologous proteins

Answer 11

Genes from higher organism may be introduced into microbial cells such that the recipients are capable of synthesising foreign proteins. These proteins are described as “heterologous” meaning derived from a different organism.

Question 12

What are the important factors in the design of the manufacturing processes by recombinant DNA technology

Answer 12

1. Product secretion
2. Minimization of product degradation
3. Control of the onset of synthesis during fermentation
4. Maximising foreign gene- expression

Question 13

What are the major groups of recombinant proteins developed as therapeutic agents

Answer 13

• Blood factors
• Thrombolytics
• Anticoagulants
• Hormones
• Growth factors
• Cytokines