Temperature-dependent biotransformation of 2,4'-dichlorobiphenyl by psychrotolerant Hydrogenophaga strain IA3-A: higher temperatures prevent excess accumulation of problematic meta-cleavage products.
OBJECTIVE
The present work investigates the possibility that temperature could regulate the pattern of transformation of 2,4'-chlorobiphenyl (2,4'-CB) by psychrotolerant Hydrogenophaga sp. IA3-A.


RESULTS
Transformation of 2,4'-chlorobiphenyl to 2- and 4-chlorobenzoic acid (2- and 4-CBA), and meta-cleavage products by cells of strain IA3-A incubated at 10 degrees C, 25 degrees C, 37 degrees C or 45 degrees C were monitored by UV spectrometry, HPLC and GC-MS analyses. Cultures incubated at 10 degrees C, 25 degrees C or 37 degrees C produced low amounts of CBAs and excess levels of meta-cleavage products from 2,4'-CB. Cultures incubated at 45 degrees C transformed most of the degraded 2,4'-CB to CBAs and low level of meta-cleavage product. Culture extracts contained unusual varieties of isomeric hydroxylated metabolic products.


CONCLUSIONS
Efficient transformation of 2,4'-CB to CBAs was possible in cultures incubated at 45 degrees C. Evidence for the involvement of multiple pathways in the transformation of 2,4'-CB in strain IA3-A suggests that differential regulation of the pathways at different temperatures was likely responsible for the change in the pattern of transformation of 2,4'-CB in cultures incubated at 45 degrees C.


CONCLUSIONS
It may be possible to condition cells to transform chlorinated biphenyls more efficiently without accumulating excess level of toxic intermediates.
Lambo
A J
AJ
Applied Microbiology and Biotechnology Laboratory, Department of Biology, Memorial University of Newfoundland, St John's, NL, Canada. adewalelambo2@hotmail.com
Patel
T R
TR
D001711:Biotransformation; D002723:Chlorobenzoates / Q000378:metabolism; D042621:Comamonadaceae / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D013696:Temperature
D002723:Chlorobenzoates; D005231:Fatty Acids, Unsaturated; C018971:2-hydroxy-6-oxo-6-phenyl-2,4-hexadienoic acid; C060415:2-chlorobenzoic acid; D011078:Polychlorinated Biphenyls; C040768:4-chlorobenzoic acid; C029907:2,4'-dichlorobiphenyl