State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, P.O. Box 2614, 73 Huanghe Road, Harbin 150090, China.
Environ Int. 2020 Jun;139:105683. doi: 10.1016/j.envint.2020.105683. Epub 2020 Mar 31.
Photo-fermentative hydrogen production, the new energy production alternative, was greatly enhanced by formed biofilm. To understand the mechanism of enhancement, the intracellular proteome and extracellular polymeric substance (EPS) during biofilm formation were investigated in this work. Experimental results indicated that a possible and effective altered system could transfer light to hydrogen. Proteins were significantly regulated, for example those related with nitrogenase, flagellin, EPS transportation and DNA duplication were up-regulated while those concerned photosystem were down-regulated. It revealed these changes of proteins contributed to positive activity of key enzymes, improved communication system and increased total light utilization efficiency thus leading to enhanced capacity of hydrogen production. Besides above metabolic changes inside the cells, EPS secreted by the bacteria played an important role in hydrogen production and its yield decided the release of hydrogen. When EPS descended to a lower concentration during biofilm formation, it meant carbon source for EPS synthesis was reduced, and more energy and reducing power could be transferred into hydrogen energy. More importantly, this work found that composition and structure of EPS were efficiently influenced by the formation of biofilm, such as benzene and O-H structure, secondary protein structure and the kinds of protein, which were important to stable biofilm and efficient hydrogen production. Therefore, final hydrogen yield was improved by altered protein and EPS resulted from biofilm formation. This study demonstrated that formation of biofilm is an efficient, ecological and attracting way to the future bio-hydrogen production.
光发酵产氢作为新能源生产的替代方法，通过形成生物膜得到了极大的增强。为了理解增强的机制，本工作研究了生物膜形成过程中的细胞内蛋白质组和细胞外聚合物（EPS）。实验结果表明，一种可能的有效改变系统可以将光转化为氢气。蛋白质的表达水平发生了显著的调节，例如与固氮酶、鞭毛蛋白、EPS 运输和 DNA 复制相关的蛋白质被上调，而与光系统相关的蛋白质则被下调。这表明这些蛋白质的变化有助于关键酶的活性提高、改善通讯系统并提高总光利用效率，从而提高产氢能力。除了细胞内的代谢变化，细菌分泌的 EPS 在产氢过程中起着重要作用，其产量决定了氢气的释放。当生物膜形成过程中 EPS 浓度降低时，意味着用于合成 EPS 的碳源减少，更多的能量和还原力可以转化为氢能。更重要的是，本工作发现生物膜的形成有效地影响了 EPS 的组成和结构，如苯和 O-H 结构、二级蛋白质结构和蛋白质种类，这对稳定的生物膜和高效的产氢至关重要。因此，通过改变生物膜形成过程中的蛋白质和 EPS，最终提高了氢气的产量。本研究表明，生物膜的形成是未来生物制氢的一种高效、生态和有吸引力的方法。
