Mcc在脱色希瓦氏菌S12电极呼吸中的作用

【目的】研究脱色希瓦氏菌S12周质空间c型细胞色素Mcc的功能,进一步探索和补充微生物胞外电子传递过程的机制。【方法】借助自杀质粒敲除mcc基因,通过细胞浓度测定和激光共聚焦显微镜比较分析突变株和野生株之间的浮游细胞和生物膜的生长情况,并比较分析二者在微生物燃料电池电极还原、铁还原和胞外偶氮染料还原过程中的功能。【结果】Mcc缺失对铁还原和偶氮还原没有影响,但却造成电极呼吸活性下降34.1%;与野生株相比,mcc突变株的好氧生长和厌氧浮游细胞生长无明显影响,但却显著抑制了电极表面生物膜的形成。【结论】Mcc是希瓦氏菌S12电极呼吸过程中周质空间电子传递的重要组分之一,缺失会显著抑制其电极呼吸效率以及生物膜的形成。

Role of Mcc in Shewanella decolorationis S12 electrode respiration

Objective] The main objectives of this study were (i) to investigate the role of Mcc, a periplasmic monohemecytochrome c, in the extracellular electron transfer process of Shewanella decolorationis S12, and (ii) to provide new information for a complete understanding of bacterial extracellular electron transfer. Methods] An mcc-mutant was created by using a suicide plasmid. The planktonic and biofilm growth of the mutant and wild type strains were compared by using cell optical density and confocal laser scanning microscope. Furthermore, the extracellular electron transfer capacities including electrode respiration, iron reduction and azo dye reduction of the two strains were analyzed. Results] Although no significant difference was detected in iron and azo dye reduction between the wild type and mutant strains, mutant strain showed 34.1% decrease in electrode respiration capacity when using electrode as electron acceptor in microbial fuel cells in comparison with the wild type strain. In microbial fuel cells, the mcc-mutant showed similar planktonic growth profile but lower electrode biofilm forming capacity compared to the wild type strain. Conclusion] The results demonstrated that Mcc played an important and specific role in the periplasmic electron transfer of S. decolorationis S12 electrode respiration, Mcc-deficiency caused significantly decrease in the electrode respiration and biofilm growth capacities of S. decolorationis S12.