Investigation of halohydrins degradation by whole cells and cell-free extract of pseudomonas putida dsm 437: A kinetic approach

Abstract

The biodegradation of two halohydrins (1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol) by P. putida DSM 437 was investigated. Intact cells of previously acclimatized P. putida DSM 437 as well as cell-free extracts were used in order to study the degradation kinetics. When whole cells were used, a maximum biodegradation rate of 3-CPD (vmax= 1.28.10-5 mmol mg-1DCW h-1) was determined, which was more than 4 times higher than that of 1,3-DCP. However, the affinity towards both halohydrins (Km) was practically the same. When using cell-free extract, the apparent vmax and Km values for 1,3-DCP were estimated at 9.61.10-6 mmol mg-1 protein h-1 and 8.00 mM, respectively, while for 3-CPD the corresponding values were 2.42.10-5 mmol mg-1 protein h-1and 9.07 mM. GC-MS analysis of cell-free extracts samples spiked with 1,3-DCP revealed the presence of 3-CPD and glycerol, intermediates of 1,3-DCP degradation pathway. 3-CPD degradation was strongly inhibited by the presence of epichlorohydrin and to a lesser extent by glycidol, intermediates of dehalogenation pathway.