Comparison of 2-chlorobenzoic acid biodegradation in a membrane bioreactor by B. cepacia and B. cepacia bearing the bacterial hemoglobin gene.

摘要: Abstract Degradation of 2-chlorobenzoic acid (2-CBA), a model recalcitrant chlorinated organic compound, by pure cultures Burkholderia cepacia strain DNT with (transformed B. ) and without (untransformed the bacterial hemoglobin ( Vitreoscilla , VHb) gene, vgb was investigated in parallel membrane bioreactors (MBRs). This done aseptically to prevent contamination during operation MBRs. The objective determine whether degradation 2-CBA cometabolism, using acetate as primary carbon source, under hypoxic conditions might be enhanced for -bearing cells removal efficiency transformed (97–99%) slightly higher than that untransformed (95–99%) at all stages. average amount chloride released from also cells, 92–96% compared 64–84% maximum theoretical amount, exact value depending on operating conditions. These results indicate degradation/transformation is not accompanied stoichiometric release strain. difference between percentages attributed persistence, conditions, chlorine atom metabolites. Growth significantly cells. For varying media compositions, reached cell densities (3.2–5.4 g/L) relative (2.8–4.7 g/L) food microorganism ratios ranging 0.44–0.59 0.38–0.49 g COD/g biomass-d observed yields thus ranged 0.16–0.20 0.15–0.18 g TSS/g COD respectively. yield depended medium composition. MBR system -containing maintained high biomass concentration oxygen limitations provided cell-free effluent. Hence, it may useful treating volumes water contaminated low levels organics.