4. Microbial Degredation Of Macromolecules

Question 1

Describe the characteristics of microbial enzymes

Answer 1

The capability and appreciable activity under abnormal conditions, mainly temperature and pH. Hence they are categorised differently as thermophilic, acidophilus or alkophilic

Question 2

List two commercial applications of proteases and the organisms that produce them

Answer 2

Amylases produced by Bacillus sp and Aspergillus niger play a role in submerged fermentation in 25% of the worlds enzyme market

• The production of glucose syrup
  
  • Paper and baking industries
  • stain removal in laundry industry

Question 3

Explain the difference between biodegradation and bioremediation. Give examples.

Answer 3

Bioremediation - the use of naturally occurring or genetically engineered microorganisms to transform harmful substances into less toxic or nontoxic compounds Eg. land farming

Biodegradation - the breakdown of organic matter by microorganisms such as bacteria and fungi, it is generally assumed to be a natural process. Eg. composting

Question 4

How can white rot destroy exposed wooden pilings in harbours?

Answer 4

White rot (phanerochaete Chrysosporum) degrades cellulose and lignin in wood, causing the wood to rot resulting in white colour of decayed wood - white rot fungus. 
	- lignin degraded only under aerobic conditions therefore normal healthy wood is not affected

Question 5

Pectinases can have both positive and negative impacts on the apple industry. Discuss both cases including the uses or problems, the mode of action and the microorganism that produces the enzyme.

Answer 5

Commercial uses:

• Wine and fruit juice industry
• Clear fruit juice > assists in pressing/juice extraction, get more juice out of the fruit (rapidase pomaliq)

Commercial problems

• apple rot caused by pectinase producing fungi (penicillium expansum
  
  • produces soft rot in apples due to complete degradation of pectin by pectinase
  • infects via wounds in apple during handling and packing (wound parasite)
  • also known as blue mould

Question 6

Detail the role of bacteria in the degradation of polysaccharides in the cows gut

Answer 6

• The rumen of cows has fibrobacter and ruminococcus sp and are hence able to breakdown cellulases
• Rumen microbes work together to break down what the cow eats, turning them feed into energy and protein for the cow. They produce volatile fatty acids for additional energy and the microbes themselves are an important protein source at the end of their life cycles.

Question 7

Hydrolysis of lipids can be an important virulence factor in some pathogenic microorganisms. Describe the enzymes, their function/role and the resultant effect.

Answer 7

• Large molecules, esters of glycerol and fatty acids
• Must be broken down to enable transport across the membrane
• An enzyme called lipase catalyses the hydrolysis of the fats and oils

Question 8

Describe the role of Penicillin Amidase in drug production.

Answer 8

• is produced naturally by many bacteria as a defence mechanism
• is the enzyme used for the production of semisynthetic penicillins
• genetically engineered strains of e-coli overproduce it
  
  • cleaves 6-APA from penicillin G
  • add different side chains
  • extends activity of penicillin to gram negatives as antibiotic can now penetrate the LPS outer membrane of gram negatives

Question 9

Naturally occurring bacteria were used to cleanup the oil spill of the Exxon Valdez. How was this achieved?

Answer 9

In 1989 around 11.2 million gallons of oil spilled into the sea.
Members of the pseudomonas genus can use crude oil for energy, growing in sea water with oil (K2PO4), use urea as nutrients. Added nutrients were spill on the shore line to accelerate the bacterial biodegradation of oil to CO2 and water.

Question 10

Extremeophiles have been used to generate enzymes of commercial significance. Give two examples detailing the enzyme, the microorganisms it is obtained from and the purpose it is put to.

Answer 10

Phanerochaete chrysosporum - is able to degrade a wide range of compounds using intracellular and extracellular enzymes
- potential use in bioreactors where liquid wastes flow past immobilised fungi and are degraded by fungal enzymes

Pseudomonas sp - is able to use NG as nitrogen source and metabolic is to mononitroglycerin.
- is found in soil at ammunitions plant