Enhancing the biodegradation of benzene, toluene, and p-xylene mixture by amplification of toluene dioxygenase genes in a hybrid pseudomonas putida
- Korea Advanced Institute of Science & Technology, Taejon (Korea, Republic of)
In order to enhance the degradation rate of BTX mixture through the hybrid metabolic pathway constructed in our previous work, DNA fragment containing the todCIC2BA genes which encode the toluene dioxygenase of P.putida F1 was cloned in the broad-host-range multicopy vector RSF1010, and then the resulting plasmid pTOD037 was introduced into P.putida mt-2 which harbors the archetypal TOL plasmid. As a result, a new hybrid strain, P.putida TB103, possessing the enhanced activity of the toluene dioxygenase in the same hybrid pathway, was constructed. The degradation rates of benzene, toluene, and p-xylene by P.putida TB103 were increased by about 9.3, 3.7, and 1.4 fold, respectively, compared with those by previously constructed P.putida TB101. Apparently, this improved capability of P.putida TB103 for the degradation of BTX mixture resulted from the amplification of the tod CIC2BA genes. Furthermore, a relatively long lag period for benzene degradation observed when P.putida TB101 was used for the degradation of BTX mixture under the low dissolved oxygen tension (DOT) disappeared when P.putida TB103 was employed. This results suggested that the expression of todCIC2BA genes became constitutive in pTOD037 not influenced by the DOT.
- OSTI ID:
- 126134
- Report Number(s):
- CONF-950402--
- Country of Publication:
- United States
- Language:
- English
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