Degradation of alkanes and highly chlorinated benzenes, and production of biosurfactants, by a psychrophilic Rhodococcus

1. Degradation of alkanes and highly chlorinated benzenes, and production of biosurfactants, by a psychrophilic Rhodococcus sp. And genetic characterization of its chlorobenzene diogenase By Peter Rapp and Lotto H.E. Gabriel-Jurgens Microbiology(2003), vol 149 Presented by Kelly Cho

2. Background Chlorobenzenes are generally from paint solvents, pesticides, and leftovers from manufacturers. Alkanes in the environment are from gas and oil spills. Harmful effects: Cancer in animals, liver, brain and/or kidney damage.

3. Background Rhodococcus sp. Are gram positive, psychrophilic and halophilic bacterium. Primarily found in soil. Degrades toxic materials and leaves a production of biosurfactants behind. Biosurfactants that were left behind were lipids, glycolipids, proteins and fatty acids. Targeted gene was TcbA and TecA dioxygenases.

4. Pathway

5. Material and Methods Isolation from a mixed contaminated batch culture. Screening and analysis, of volatile and salt broth, serial dilution and determination of cell growth. Cell extractions were done, and soluble protein concentration was determined by using a Bradford method.

6. Material and Methods Gas uptake and released were carefully measured by using specific rates, and Oxygen determination was done by polarographic analysis that measures dissolved oxygen Chloride gas released was measured by mercury(II) thiocynate method and protein concentration of cell suspensions.

7. Material and Methods PCR amplification Cloning and screening was done with QIAquick PCR kit and ligation was done on pGEM-T- vector. Luria-Bertani plates with ampicillian and X-gal were used. Sequences were submitted to European Molecular Biology Laboratory to determine most similar match.

8. Material and Methods Dihydrodial dehydrogenase activity was determined by NAD+ reduction. This was determined by using a TLC method. Rf value is .41, solvent system of methyl chloride, water and methanol, and sprayed with anisaldehyde and sulfuric acid. Sugars, trehalose lipids and glycolipids are the suggested biosurfactants.

9. Results

10. Results

11. Results

12. Discussion Rhodococcus sp. Was able to grow on many different alkanes and chlorobenzene showing that it could be used on many different type of contaminated areas. Rhodococcus also had evidences to degrade a range of mono- to tetra- chlorobenzenes. Biosurfactants that are produced are much safer material and can be much easily degraded in the environment.

13. References http://en.wikipedia.org/wiki/Alkanes http://umbbd.msi.umn.edu/cb/cb_map.html http://www.atsdr.cdc.gov/toxprofiles/tp131.html Microbial production of biosurfactants and their importance N. G. K. Karanth, P. G. Deo and N. K. Veenanadig* Pesticide Residue Abatement Lab, Food Protectants and Infestation Control Department, Central Food Technological Research Institute, Mysore 570 013, India*Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India Degradation of alkanes and highly chlorinated benzenes, and production of biosurfactants, by a psychrophilic Rhodococcus sp. And genetic characterization of its chlorobenzene diogenase By Peter Rapp and Lotto H.E. Gabriel-Jurgens Microbiology(2003), vol 149