Effects of low concentration heavy metals on biodegradation of BDE209 by Bacillus cereus

In view of joint contamination of heavy metals and polybrominated diphenyl ethers (PBDEs) caused by electronic-wastes, analysis measures of GC-MS, ICP, UV scanning, fTIR, SEM, etc. were used to research on the debromination of deca-brominated diphenyl ethers (BDE209) and biodegradation capability under aerobic condition by combined Bacillus cereus XPB and XPC, and the effects of low concentrations of heavy metals on the biodegradation of BDE209 were also studied. The experimental results showed that combined Bacillus cereus efficiently debrominated and degraded BDE209 to hydroxybenzenes, and the highest debromination capability of 1.18 mg x L(-1) with the efficiency of 14.16% at least was achieved after 1 d reaction. Although biodegradation process was delayed at presence of low concentrations of heavy metals, satisfying degradation effect was still achieved with debromination efficiency of not less than 13.92%. Hydroxy, a minoacyl, and alkyl were confirmed to be the key functional groups for combined Bacillus cereus to biodegrade BDE209 and adsorb heavy metals. Obvious release of K+ and Na+ was observed and the release quantity rose up from 148.867 micromol x g(-1) and 225.835 micromol x g(-1) respectively, when only biodegradation was involved, to 156.482 micromol x g(-1) and 261.217 micromol x g(-1) individually when biodegradation and biosorption acted simultaneously. During the process of BDE209 biodegradation, the highest adsorption rates for Pb2+, Zn2+, and Cu2+ by combined Bacillus cereus were 89.47%, 72.22% and 39.83% respectively.