五株产MnCO_3细菌的除锰特性

Manganese Removal Mechanisms of Five Bacterial Strains with the Abilities to Produce MnCO_3

本研究从湖南省某锌锰矿矿口和天津市西青玛钢厂锰原料仓库土样中富集分离获得5株对锰有去除能力的抗锰细菌,将其命名为J2-3、J4-3、J12-1、JM3-2和JD。形态学、生理生化分析和16SrRNA基因测序等结果表明它们分别归属为氢噬孢菌属、分枝杆菌属、红球菌属、不动杆菌属和芽孢杆菌属。JD和JM3-2菌的Mn(Ⅱ)抗性最低抑制浓度(MIC)为2mmol/L,J2-3、J4-3和J12-1菌为12mmol/L。X射线晶体衍射分析表明这5株抗锰菌随生长生成了MnCO3沉淀而将Mn(Ⅱ)从溶液中去除。其中JD和JM3-2的锰去除率分别为94.28%±0.1%和93.10%±3.1%。其他菌的锰去除率也均在85%以上。研究发现培养基的pH由起始的7.0变为最终8.5以上,推测其除锰原理可能是由于菌体代谢改变了培养基pH而将可溶的MnCl2转化为不溶的MnCO3沉淀。本研究证实了和以往报道的锰氧化细菌不同的新型除锰细菌。

Five manganese-resistant and manganese-removing bacterial strains were isolated from soil samples of a Zn-Mn mine in Hunan and manganese storage of Xi Qingma steel factory in Tianjin and named as J2-3, J4-3, J12-1, JM3-2 and JD. Based on morphological, physiological/biochemical tests and 16S rRNA gene analysis, these strains were identified as Hydrogenophaga, Mycobacterium, Rhodococcus, Acinetobacter and Bacillus respectively. The minimal inhibitory concentration （MIC） of JM3-2 and JD were 2 mmol/L while MIC of J2-3, J4-3, and J12-1 reached 12 mmol/L. The X-ray diffraction analysis showed that the precipitate formed by the Mn（ Ⅱ ）-removal bacteria was MnCO3. All of the 5 strains could remove manganese effectively （ 〉 85%）. Strains JD and JM3-2 removed 94.28% ± 0.1% and 93.10% ± 3.1% Mn（ Ⅱ） from the medium, respectively. During the removing process, the pH increased from 7.0 to more than 8.5. This indicated the mechanism of manganese removing may caused by the metabolism of the Mn（ Ⅱ ）-removing bacteria to transform of soluble Mn（Ⅱ） into the insoluble MnCO3 when pH increased. Here we report a new-type of manganese-removing bacteria, which is different from the maga-nese-oxidizing bacteria reported before.