Zhu Xiuping, Siegert Michael, Yates Matthew D, Logan Bruce E
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
Appl Environ Microbiol. 2015 Jun;81(11):3863-8. doi: 10.1128/AEM.00594-15. Epub 2015 Mar 27.
Microbial electrosynthesis (MES) systems with mixed cultures often generate a variety of gaseous and soluble chemicals. Methane is the primary end product in mixed-culture MES because it is the thermodynamically most favorable reduction product of CO2. Here, we show that the peptaibol alamethicin selectively suppressed the growth of methanogens in mixed-culture MES systems, resulting in a shift of the solution and cathode communities to an acetate-producing system dominated by Sporomusa, a known acetogenic genus in MES systems. Archaea in the methane-producing control were dominated by Methanobrevibacter species, but no Archaea were detected in the alamethicin-treated reactors. No methane was detected in the mixed-culture reactors treated with alamethicin over 10 cycles (∼ 3 days each). Instead, acetate was produced at an average rate of 115 nmol ml(-1) day(-1), similar to the rate reported previously for pure cultures of Sporomusa ovata on biocathodes. Mixed-culture control reactors without alamethicin generated methane at nearly 100% coulombic recovery, and no acetate was detected. These results show that alamethicin is effective for the suppression of methanogen growth in MES systems and that its use enables the production of industrially relevant organic compounds by the inhibition of methanogenesis.
具有混合培养物的微生物电合成（MES）系统通常会产生多种气态和可溶性化学物质。甲烷是混合培养MES中的主要终产物，因为它是二氧化碳热力学上最有利的还原产物。在此，我们表明，短杆菌肽A选择性地抑制了混合培养MES系统中产甲烷菌的生长，导致溶液和阴极群落转变为以芽孢八叠球菌为主的产乙酸系统，芽孢八叠球菌是MES系统中一种已知的产乙酸菌属。产甲烷对照中的古菌以短柄产甲烷杆菌为主，但在经短杆菌肽A处理的反应器中未检测到古菌。在超过10个循环（每个循环约3天）的时间里，用短杆菌肽A处理的混合培养反应器中未检测到甲烷。相反，乙酸的平均产生速率为115 nmol ml⁻¹ 天⁻¹，与先前报道的卵形芽孢八叠球菌在生物阴极上的纯培养速率相似。没有添加短杆菌肽A的混合培养对照反应器以近100%的库仑回收率产生甲烷，未检测到乙酸。这些结果表明，短杆菌肽A对抑制MES系统中产甲烷菌的生长有效，并且其使用能够通过抑制产甲烷作用来生产与工业相关的有机化合物。
