Shewanella oneidensis MR-1对硫化汞的生物利用性研究

Research on the Bioaccesibility of HgS by Shewanella oneidensis MR-1

在实验室模拟条件下,研究了铁还原菌奥奈达希瓦式菌Shewanella oneidensis MR-1对固态硫化汞的生物溶解、生物甲基化作用及其影响因素.结果表明,铁还原菌S.oneidensis MR-1在含硫培养基中生长良好,低浓度硫素能够促进其生长,高浓度时细菌生长则受到抑制,这种抑制主要表现在菌株生长曲线迟缓期的延长;铁还原菌S.oneidensis MR-1能够利用固态硫化汞,促进其溶解并迅速进行汞甲基化;在S.oneidensis MR-1的耐硫化物范围内,菌株对硫化汞的生物溶解作用随着硫化钠浓度的增大而增强,但生物甲基化作用只在低浓度硫化钠时受到促进,硫化钠浓度过高时则会受到抑制;此外,弱酸性环境比酸性及中碱性的环境更有利于S.oneidensis MR-1对硫化汞的生物溶解及甲基化.

The biological dissolution and methylation of solid HgS by Shewanella oneidensis MR- 1 and influenced factors under laboratory conditions were studied. Results showed that S. oneidensis MR-1 could grow well at the low concentration of Na2S, but its growth was inhibited at the high concentration of Na2S, which mainly happened in the prolonged lag phase. Iron reducing bacteria S. oneidensis MR-1 could access the solid mercuric sulfide, and rapidly promote the biological dissolution and methylation of HgS. In the appropriate range of sulfide to S. oneidensis MR-1, the biological solubility of HgS was enhanced with the increasing concentration of Na2S, but the methylation just promoted at the low Na2S concentration, and it would be inhibited when the concentration is high. In addition, weakly acidic environment was more beneficial to biological dissolution and methylation of HgS than acidic, neutral or alkaline conditions by S. oneidensis MR-1.