Biodegradation

Biodegradation

1. Biodegradation

2. Degradation Degradation is breakdown of complex organic material into simpler one. Different ways of degradation: 1. Photodegradation by natural day light 2. Oxidation by chemical additives(Catalysts) 3. Thermal degradation by heat 4. Mechanical degradation by mechanical force 5. Biodegradation by Microorganisms.

3. Degradation Three levels of degradations: 1. Rapid degradation(day- week): HC compounds 2. Slow breakdown(Months- years): HC polymers/ Halogenated compounds 3. No degradation: Recalcitrant/ Xenobiotic: Plastic

4. Biodegradation “Natural and complex process of decomposition facilitated by biochemical reactions.” It is biological transformation of a complex organic material to simpler by MOs. Reduced organic materials are thermodynamically unstable and oftenly attacked by microbial enzymes. Biodegradibility : Quality, representing the susceptibility of the substrate to biological transformation. Natural recycling of matter which mediated by large consortium of Mos.

5. Types of Biodegradation 1. Primary biodegradation: Biochemical ways of catalysts where transformation or alteration in chemical structure of a compound occurs by biochemical reactions. Results in loss of specific property- partial biodegradation and leaves molecule mostly intact. Not desirable due to toxicity issues. Ex. Change in toxic halogen group from Pera to Meta position. Azo dye Amino benzene

6. Types of Biodegradation 2. Acceptable biodegradation: Biological conversion of toxic compounds to non toxic by biological means. Removal of undesirable characteristics occurs. Complete removal of toxic entity occurs.

7. Types of Biodegradation 3. Ultimate biodegradation: The level of degradation where the compound is totally utilized and results in production of CO 2 , water and mineral constituents. Molecular cleavage is so extensive that it removes all chemical, biological and toxic properties. The ultimate products are highly stable and can’t be degraded further.

8. Reactions involved in Biodegradation Oxidative reaction Reductive reaction Hydrolytic reaction (water) Conjugative reaction (Methylation, Acetylation)

9. Factors affecting Biodegradation

10. Factors affecting Biodegradation

11. Factors affecting Biodegradation

12. Factors affecting Biodegradation

13. Organisms responsible for biodegradation

14. Organisms responsible for biodegradation Other lower organism- algae and invertebrates too possess some of the criteria- Earthworm, but their biodegradative potential is still unknown. Marine bio-degraders: Bacteria and Fungi Soil bio-degraders: Bacteria and Fungi Mutations are very often in bacteria and is very useful for progressive adaptation towards the biodegradation pathways. Not all microbe are equipped with all enzyme, so many of them follow…. COMETABOLISM

15. Organisms responsible for biodegradation

16. Reactions involved in Biodegradation Three categories of biodegradation: I. Usable immediately II. Usable following acclimatization III. Recalcitrant IV. Cometabolic reaction

17. Reactions involved in Biodegradation I. Usable immediately Simple sugars, amino acids and fatty acids- direct utilization. The enzymes required for breakdown are either constitutive or inducible. This requires minimum acclimatization period. II. Usable following the acclimatization: A lag phase is required for adaptation where no degradation or very little degradation occurs.

18. Reactions involved in Biodegradation During lag phase  induction of enzyme occurs Duration of acclimatization period varies from few hrs to days or even weeks depending on biodegradability. Example: lag phase of 50 days in pyrazon degradation. III. Recalcitrant/ Xenobiotic: Naturally occurring substances such as lignin as well as anthropogenic.