1. Genetics of Microbial Biodegradation

2. Adenine (A) & thymine (T), Guanine (G) & cytosine (C)
Double helix
DNA combined with protein
Purine
Purine
Adenine (A) & thymine (T),
Guanine (G) & cytosine (C)

3. Contaminants Microbial bioremediation depends on
Genetics of Microbial Biodegradation
Contaminants Microbial bioremediation depends on
Existing microbial genome
MO’s change to modify existing genome
Contaminants + MO’s  Metabolite

4. Microbial genetic plasticity 소성 (change the structure)
Evolution 진화
Mutation 돌연 변이
Insertion or deletion or substitution of nucleotide
New metabolic potential to degrade xenobiotic depends on alteration or exchange of genetic information

5. DNA replication or repair error
Mutation 돌연 변이
DNA replication or repair error
Conversion, duplication & transposition important role in rearrangement of DNA fragments and activation and inactivation of cryptic gene.
Cryptic genes: Silent DNA sequences, not normally expressed during life cycle

6. Deletions Duplications Translocations
Inserted additional copy of chromosome
Broken portion of chromosome attaches itself to second chromosome
Lost the portion of chromosome

7. Microbes receive or lose genetic materials during
Conjugation
Transformation
Transduction
Conjugation

8. Plasmid 플라스미드 important role
To transform information from host to recipients
Gene study in field is difficult
Plasmid  small, circular, double-stranded DNA molecule - distinct from cell's chromosomal DNA 

9. Microbial community adopt to contaminants
Natural selection of mutants to possessing degradative enzymes
New metabolic activities
Protein sequence analysis give information about genetic mechanisms of adaptation

10. Role of plasmids in bioremediation
Species identified Pseudomonas
Development of new degradative enzyme
Biodegradation augmented by surfactants with nutrients & inoculation biomass
Fixed by environmental condition
Degradative enzyme in plasmid transferred variety of bacterial species in many genera
Plasmid important mechanisms for genetic adaptation
Bacteria in various waste
Available in contaminated free environment
Plasmid containing bacteria
Transfer plasmid by conjugation

11. Evolution barriers for new microbes
New microbes unable to evolve for degradation of various chemicals due to
Low contaminant concentration insufficient for growth
Not enough time for microbes to evolve for newly introduced chemicals
Low selective pressure to enrich microbes
Before mutation toxicity kills microbes
Fluctuation level of contaminants

12. Enhancement of novel microbial degradative abilities
Primary mechanism for Degradation
Random mutation & Environmental Selection
After adaptation
Interaction difficult to stop in field condition
Degradative character continue to next generation
High growth & dense microbial population
Due to
Genetic fitness
Rapid reproductive rate

13. Genetics & Gene manipulation
Genetic mechanisms of adoptation
Gene transfer, Genetic mutation (DNA rearrangement, Gene duplication, transposition & activation by insertion)

14. 3 Main mechanisms of genetic transfer & recombination
Lead to new combinations of alleles among bacteria
Transduction (bacteriophage mediated transfer DNA)
Transformation
(DNA uptake process)
Conjugation (Donor & recipient direct contact)

15. Practically modify microbes
In vivo
In vitro
Usual genetic transfer mechanisms
Time consuming & unpredictable
Resulting microbes genetically altered
Expand the natural limit of gene alteration
Fast, efficient & predictable

16. Metagenomics in Bioremediation
Isolation Of DNA
Manipulation of DNA
Metagenomic process starts by extracting DNA from different types of environments from microbial community
DNA fragment then merged with bacteria vector to become a cloned metagenomic DNA fragment