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Stress Survival of a Genetically Engineered Pseudomonas in Soil Slurries: Cytochrome P‐450cam‐Catalyzed Dehalogenation of Chlorinated Hydrocarbons
Author(s) -
Rattan Kavita,
Shanker Rishi,
Khanna Purushottam,
Atkins William M.
Publication year - 1999
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp990097x
Subject(s) - pseudomonas putida , biodegradation , chemistry , reductive dechlorination , biotransformation , cytochrome , tetrachloroethylene , pseudomonas , substrate (aquarium) , microorganism , food science , environmental chemistry , slurry , microbiology and biotechnology , bacteria , biochemistry , organic chemistry , biology , trichloroethylene , ecology , environmental engineering , enzyme , engineering , genetics
Biological treatment of hazardous chemical wastes has potential as an effective, practical, and economically viable process in above the ground treatment systems that consist of both genetically engineered microorganisms (GEMs) and bioreactors with process control instruments to create ideal conditions for biodegradation. A strain of Pseudomonas putida coexpressing cytochrome P‐450cam and luciferase (lux) that provides both the reductive detoxification potential of the hemoprotein and a mechanism for its reduction in the absence of “normal” P‐450 redox partners was evaluated for its ability to survive and remain metabolically competent under nutrient stress in soil slurry microcosms. More than 74% of the cells of engineered Pseudomonas were culturable after 7 days of multiple nutrient (C,N,P) starvation. The diagnostic luminescence and carbon monoxide‐difference spectra for the two engineered traits could be detected in a significant fraction of the surviving population. The GEM could be revived after repeated desiccation and starvation using Luria broth, benzoate, or citrate as nutrients. Soil slurries inoculated with the GEM transformed hexachloroethane (HCE) to tetrachloroethylene (tetraCE) 8–10‐fold faster than uninoculated slurries. The GEM also transformed the insecticide, γ‐HCH (γ‐3,4,5,6‐hexachlorocyclhexene), to γ‐3,4,5,6‐tetrachlorocyclohexene (γtetraCH) in soil slurries under subatmospheric conditions. These results indicate that GEMs can be constructed with broad substrate range detoxification catalysts such as cytochrome P‐450 for remediation.