U. Heinze et Hj. Rehm, BIODEGRADATION OF DICHLOROACETIC ACID BY ENTRAPPED AND ADSORPTIVE IMMOBILIZED XANTHOBACTER-AUTOTROPHICUS GJ10, Applied microbiology and biotechnology, 40(1), 1993, pp. 158-164
The degradation of dichloroacetic acid (DCA) by free, Ca-alginate entr
apped and adsorptive immobilized cells of Xanthobacter autotrophicus G
J10 has been studied in various experimental systems. Entrapped cells
tolerated increasing concentrations of DCA better than free cells. Fre
e and adsorptive immobilized cells degraded DCA most effectively at ma
xiMUM O2 supply, 34-degrees-C and an initial pH value of 8.0. The degr
adation of high DCA concentrations led to a decrease in the pH value a
nd to a stagnation of mineralization, particularly with free or entrap
ped cells. Due to the stabilization of pH, the supplementation of acet
ate or succinate resulted in a complete degradation of higher DCA conc
entrations. Higher degradation rates than in shake cultures were achie
ved in air-bubble and packed-bed fermentors. DCA was mineralized faste
r by free or entrapped X. autotrophicus GJ10 than by adsorptive immobi
lized cells, which, however, were able to remove higher DCA concentrat
ions. The results of the recent investigations with immobilized X. aut
otrophicus GJ10 are an important prerequisite for the application of t
his bacterium in waste treatment systems.