低浓度重金属对蜡状芽孢杆菌复合菌降解BDE209性能的影响

Effects of Low Concentration Heavy Metals on Biodegradation of BDE209 by Bacillus cereus

针对电子废弃物引起的重金属及多溴联苯醚(PBDEs)复合污染问题,采用GC-MSI、CP、紫外扫描、红外光谱等分析方法,研究了蜡状芽孢杆菌(XPB、XPC)复合菌对十溴联苯醚(BDE209)的好氧脱溴降解性能及低浓度重金属对其降解特性的影响.结果表明,复合菌对BDE209有良好的脱溴性能,能将其降解为酚类有机物,反应1 d时其最高脱溴量可达1.18 mg.L-1,脱溴率至少为14.16%.低浓度重金属的存在虽减缓BDE209的降解速率,但依然能保持良好的降解效果,脱溴率仍至少达13.92%.复合菌降解BDE209和吸附重金属的过程主要与羟基、酰胺基团和C—H键有关.单一降解BDE209过程中,复合菌大量释放K+和Na+,最高释放量分别为148.867和225.835μmol.g-1.复合菌在降解BDE209并吸附重金属的过程中,也存在K+和Na+的大量释放现象,且释放量高于单一的降解过程,最高释放量分别为156.482和261.217μmol.g-1.菌体降解BDE209的同时,对Pb2+、Zn2+、Cu2+的吸附率最高值分别为89.47%7、2.22%、39.83%.

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-hrominated 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· 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 μmol· g^-1 and 225. 835 μmol·g^-1 respectively, when only biodegradation was involved, to 156.482 μmol· g^-1 and 261.217 μmol· g^-1 individually when biodegradation and biosorption acted simultaneously. During the process of BDE209 biodegradation, the highest adsorption rates for Pb^2＋ , Zn^2＋ , and Cu^2＋ by combined Bacillus cereus were 89.47% , 72.22% and 39.83% respectively.