Biodegradation of Pentachloroethane by expressing the Pseudomonas putida Cytochrome P450cam in the purple non-sulfur phototrophic bacteria

• Main Authors: Chia-Ching Lin, 林佳靜
• Other Authors: 黃介辰
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/35499540626178601073

碩士 === 國立中興大學 === 生命科學系所 === 96 === Environmental contaminants, such as anthropogenic chlorinated compounds tri-chloroethylene (TCE) and tetrachloroethylene (PCE), can be reductively dehalogenated to less chlorinated ethenes or innocuous compounds by micro-organisms through halorespiration under anaerobic condition. The halorespiration is composed of electron donor, electron carrier, and electron acceptor. Most of these microorganisms can use hydrogen as electron donor to proceed reductive dehalogenation. The decomposition of chlorinated compound as the major targets for bioremediation with hydrogen-producing microorganisms by using co-culture. Here we construct the genes enconding cytochrome P450cam gene (camC, camA, and camB) expressed in a photosynthetic hydrogen-producing microorganisms Rhodo-pseudomonas palustris CGA009. Under anoxic condition, pentachloroethane (PCA) that bind at the camphor-binding site could be reduced by the camC of cytochrome P450cam gene. We use pentachloroethane as a model substrate for characterizing genetically engineered bacteria containing theses enzyme systems. The Rhodopseudomonas palustris CGA009 express gene including pMG105, pMG-camC, and pMG-camCAB were analyzed by using RT-PCR to monitor RNA expression. In order to analysis the biodegradation of pentachloroethane, the engineered strain carried the pMG-camCAB plasmid exhibited the predominant rate of the PCA degradation and production of hydrogen rather than pMG105 and pMG105-camC strains. Two strains of pMG105 and pMG-camCAB absence of the ability to grow on 3-Chlorobenzoate and 3-Chlorobenzoate plus Benzoate as carbon source. Probably no chlorinated benzoate or benzoate were degraded by Rhodopseudomonas palustris CGA009 two strains.