M. Meusel et Hj. Rehm, BIODEGRADATION OF DICHLOROACETIC ACID BY FREELY SUSPENDED AND ADSORPTIVE IMMOBILIZED XANTHOBACTER-AUTOTROPHICUS GJ10 IN SOIL, Applied microbiology and biotechnology, 40(1), 1993, pp. 165-171
Xanthobacter autotrophicus GJ10 was applied in a packed-bed fermentor
to degrade dichloroacetic acid (DCA) in batch-, semicontinuous and con
tinuous culture. Degradation has been studied with freely suspended an
d adsorptive immobilized cells. To imitate natural soil systems, the f
ermentor was filled with sand. Concentrations of up to 20 mM DCA were
degraded completely. If higher initial concentrations were used, the d
ecrease in pH value inhibited further growth and degradation. In conti
nuous culture the fermentor was inoculated additionally with activated
sludge. Over a period of 2 weeks the specialized strain could be reta
ined and no decrease in metabolic activity was observed. A decrease in
degradation of DCA was observed when succinate was added as a second
substrate. The haloacid dehalogenase was found to be induced by DCA. N
on-induced cells showed typical repression of catabolites and diauxic
growth with succinate as co-substrate. The results demonstrate that X.
autotrophicus GJ10 might be suitable for applications in biological w
aste treatment systems.