Zhao Zhiqiang, Li Yang, Zhang Yaobin, Lovley Derek R
Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Department of Microbiology, University of Massachusetts, Amherst, MA 01003-9298, USA.
iScience. 2020 Nov 10;23(12):101794. doi: 10.1016/j.isci.2020.101794. eCollection 2020 Dec 18.
Anaerobic digestion was one of the first bioenergy strategies developed, yet the interactions of the microbial community that is responsible for the production of methane are still poorly understood. For example, it has only recently been recognized that the bacteria that oxidize organic waste components can forge electrical connections with methane-producing microbes through biologically produced, protein-based, conductive circuits. This direct interspecies electron transfer (DIET) is faster than interspecies electron exchange via diffusive electron carriers, such as H. DIET is also more resilient to perturbations such as increases in organic load inputs or toxic compounds. However, with current digester practices DIET rarely predominates. Improvements in anaerobic digestion associated with the addition of electrically conductive materials have been attributed to increased DIET, but experimental verification has been lacking. This deficiency may soon be overcome with improved understanding of the diversity of microbes capable of DIET, which is leading to molecular tools for determining the extent of DIET. Here we review the microbiology of DIET, suggest molecular strategies for monitoring DIET in anaerobic digesters, and propose approaches for re-engineering digester design and practices to encourage DIET.
厌氧消化是最早开发的生物能源策略之一，但对于负责甲烷产生的微生物群落之间的相互作用，人们仍然知之甚少。例如，直到最近人们才认识到，氧化有机废物成分的细菌可以通过生物产生的、基于蛋白质的导电电路与产甲烷微生物建立电连接。这种直接种间电子转移（DIET）比通过扩散性电子载体（如氢气）进行的种间电子交换更快。DIET对诸如有机负荷输入增加或有毒化合物等干扰也更具弹性。然而，在当前的消化器实践中，DIET很少占主导地位。与添加导电材料相关的厌氧消化改进归因于DIET的增加，但缺乏实验验证。随着对能够进行DIET的微生物多样性的进一步了解，这一不足可能很快会被克服，这也将带来用于确定DIET程度的分子工具。在这里，我们回顾了DIET的微生物学，提出了监测厌氧消化器中DIET的分子策略，并提出了重新设计消化器设计和实践以促进DIET的方法。
