改性蓝藻生物炭促进微生物电合成系统产乙酸的机制研究

The promotion microbial electrosynthesis system for acetate production by modified Cyanobacterial biochar addition

微生物电合成系统(MES)是一种以微生物作为催化剂,在阴极电驱动下还原CO_(2)产生简单化学品的新型碳捕获利用技术.为探究蓝藻生物炭在MES中的添加强化乙酸合成的潜力,本研究通过不同蓝藻生物炭的投加,检测乙酸合成性能及电子回收率,观察阴极微生物分布及形态特征,分析微生物群落结构特征,探究蓝藻生物炭添加对乙酸合成的影响及机制.结果表明,添加蓝藻生物炭(ABC)和过氧化氢改性蓝藻生物炭(ABC-H2O_(2)),使MES乙酸产量分别增加了33.8%和77.0%,电子回收率均有所上升,且ABC-H2O_(2)组电子回收率高于ABC组.分析蓝藻生物炭电子传递性能和氧化还原活性表明,经过氧化氢改性后的蓝藻生物炭表面含氧官能团数量增加,增强了电子传递能力及氧化活性,有利于微生物通过蓝藻生物炭介导进行间接电子传递.在微生物群落结构方面,蓝藻生物炭的添加降低了产乙酸菌丰度,但提高了微生物群落中电活性微生物和产氢微生物的丰度,使得产乙酸微生物获得更多的电子,实现乙酸合成性能增强.本研究揭示了蓝藻生物炭,特别是改性蓝藻生物炭对MES乙酸合成的强化作用,为强化MES还原CO_(2)产乙酸提供新的思路.

Microbial electrosynthesis system(MES)is a new carbon capture and utilization technology,in which microorganisms act as catalysts and reduce CO_(2) to simple chemicals under electric power.For exploring the performance and mechanisms of acetate synthesis in the Cyanobacterial biochar addition,the acetate concentration and electron recovery rate were examined,and microbial morphology and community structure were analyzed.The results showed that the acetate concentration of Cyanobacterial biochar(ABC)and hydrogen peroxide modified Cyanobacterial biochar(ABC-H2O_(2))were increased by 33.8%and 77.0%,respectively,and the electron recovery rate of ABC-H2O_(2) group was higher than that of ABC group.The analysis of electron transfer performance and redox activity of biochar showed that the oxygen-containing functional groups on the surface of ABC-H2O_(2) increased,which enhanced the capacity of oxidation activity and electron transfer,and was beneficial for microorganisms to obtain electrons from biochar.The abundance of acetogens was reduced,while the abundance of electroactive and hydrogen-producing microorganisms were increased in the addition of biochar.The biochar addition is mainly to provide more sufficient electrons for acetogens and increase the abundance of electroactive and hydrogen-producing microorganisms.This study evaluated the influencing factors of acetate production with the addition of modified biochar,hence provided a new insight for enhancing the acetate synthesis in MES.