微生物电合成生产中链脂肪酸的基本原理及研究进展

doi:10.13560/j.cnki.biotech.bull.1985.2020-1054

摘要/Abstract

摘要：

微生物电合成（microbial electrosynthesis,MES）是一种新型微生物电化学技术,以电能驱动微生物在温和条件下转化水和CO₂生成有机物。中链脂肪酸（medium-chain fatty acids,MCFAs）是指C6至C12的一元饱和羧酸,是重要的化工原料和农用产品。微生物生产MCFAs通常包括一次发酵和二次发酵过程：一次发酵即微生物将单体和多聚物氧化为中间产物丙酮酸盐,并最终生成短链脂肪酸和醇以及H₂和CO₂等小分子物质;二次发酵为微生物对一次发酵的产物再利用,包括碳链延长产生中链脂肪酸。MES生产MCFAs可望获得比传统有机废弃物厌氧发酵途径生产MCFAs更高的能量效率,并有望以获得高附加值产物的方式推进MES技术的实用化。综述了MES催化转化C1废气并耦合二次发酵过程进行碳链延长产生MCFAs的研究现状,分析代谢路径及功能微生物,探讨电极材料以及关键运行参数,为MES生产MCFAs的进一步发展提供重要的科学依据和技术支持。

关键词: 微生物电合成, 碳链延长, 中链脂肪酸, C1废气

Abstract:

Microbial electrosynthesis（MES）is a novel microbial electrochemical technology,which utilizes the electric energy to drive the microbial production of organic compounds from water and CO₂ under mild conditions. Medium-chain fatty acids（MCFAs）are defined as saturated monocarboxylic acids with a carbon chain in the range from C6 to C12,and are important chemicals with various industrial and agricultural applications. Microbial production of MCFAs usually involves the primary and secondary fermentation process. Primary fermentation is the conversion of monomers and polymers into pyruvic acid as intermediate to produce short chain fatty acids,alcohols,H₂,and CO₂as the final products. Secondary fermentation is the further reuse of the final products from primary fermentation,including the chain elongation for MCFAs production. MCFAs production in MES is expected to obtain a higher energy efficiency than that of traditional anaerobic fermentation of organic waste,and is also expected to promote the practical application of MES technology itself with high value-added products. This paper reviews recent advances of MCFAs production in MES,by integrating the catalytic conversion of C1 waste gas with secondary fermentation（chain elongation）,and discusses the metabolic pathways,functional microorganisms,electrode materials,as well as key operating parameters,aiming to provide important scientific and technical support for further development of MCFAs production in MES.

Key words: microbial electrosynthesis, chain elongation, medium-chain fatty acids, C1 waste gas

褚娜, 蒋永, 曾建雄. 微生物电合成生产中链脂肪酸的基本原理及研究进展[J]. 生物技术通报, 2021, 37(5): 237-247.

CHU Na, JIANG Yong, ZENG Jian-xiong. Principle and Research Progress in Microbial Electrosynthesis of Medium-chain Fatty Acids[J]. Biotechnology Bulletin, 2021, 37(5): 237-247.

图/表 5

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底物 Substrates	阴极材料 Cathode materials	功能菌群 Microbial community	主要产物 Main products	最大MCFAs选择性Maximum of MCFAs selectivity /(%) ^a	最大MCFAs产率 Maximum of MCFAs production rate/ (g·L^-1·d^-1)	最大MCFAs产量Maximum of MCFAs concentration/ (g·L^-1)	MCFAs延滞期 Lage phase for producing MCFA/d	参考文献 Reference
CO₂	石墨颗粒 Graphite particle	Clostridium spp.	乙酸、丁酸、异丁酸和己酸 Acetate, butyrate, isobutyrate, and aproate	-	-	0.3	-	[39]
CO₂	石墨颗粒 Graphite particle	Clostridium spp.	乙酸、丁酸、异丁酸和己酸 Acetate, and butyrate, isobutyrate, aproate	-	0.04	1.2	240	[18]
CO₂	碳毡 Carbon felt	-	乙酸、丁酸和己酸Acetate, butyrate, and caproate	12.8	1.50	1.5	164	[43]
CO₂	碳毡 Carbon felt	-	乙酸、丁酸和己酸Acetate, butyrate, and caproate	19.7	2.00	3.1	171	[44]
CO₂/CO	碳毡 Carbon felt	Acetobacterium、Oscillospira、Clostridium spp.	乙酸、丁酸和己酸Acetate, butyrate, and caproate	15.4 ^b	0.06	0.8	44	[19]
CO₂/乙醇CO₂/ thanol	碳毡 Carbon felt	Acetobacterium、Clostridium spp.	丁酸、己酸和庚酸Butyrate, caproate, and heptanoate	80.3	2.41	7.7	<1	[45]
乙酸 acetate	石墨毡 Graphite felt	Clostridium kluyveri	丁酸、己酸和辛酸Butyrate, caproate, and caprylate	26.0	0.19	0.8	-	[40]
乙酸/乙醇 acetate / ethanol	无极电 Without electrode	Acetoanaerobium、Dysgonomonas、Clostridium spp.	丁酸、己酸Butyrate, and caproate	60.0	3.40	10.0	1	[46]
甘油glycerol	石墨板 Graphite plate	Citrobacter、Pectinatus、lostridium spp.	丙酸和戊酸Propionate, and valerate	-	-	-	-	[8]
甘油glycerol	石墨板 Graphite plate	Citrobacter、Pectinatus、Clostridium spp.	乙酸、丙酸和丁酸Acetate, ropionate, and butyrate	-	-	-	-	[47]

底物 Substrates	阴极材料 Cathode materials	功能菌群 Microbial community	主要产物 Main products	最大MCFAs选择性Maximum of MCFAs selectivity /(%) ^a	最大MCFAs产率 Maximum of MCFAs production rate/ (g·L^-1·d^-1)	最大MCFAs产量Maximum of MCFAs concentration/ (g·L^-1)	MCFAs延滞期 Lage phase for producing MCFA/d	参考文献 Reference
CO₂	石墨颗粒 Graphite particle	Clostridium spp.	乙酸、丁酸、异丁酸和己酸 Acetate, butyrate, isobutyrate, and aproate	-	-	0.3	-	[39]
CO₂	石墨颗粒 Graphite particle	Clostridium spp.	乙酸、丁酸、异丁酸和己酸 Acetate, and butyrate, isobutyrate, aproate	-	0.04	1.2	240	[18]
CO₂	碳毡 Carbon felt	-	乙酸、丁酸和己酸Acetate, butyrate, and caproate	12.8	1.50	1.5	164	[43]
CO₂	碳毡 Carbon felt	-	乙酸、丁酸和己酸Acetate, butyrate, and caproate	19.7	2.00	3.1	171	[44]
CO₂/CO	碳毡 Carbon felt	Acetobacterium、Oscillospira、Clostridium spp.	乙酸、丁酸和己酸Acetate, butyrate, and caproate	15.4 ^b	0.06	0.8	44	[19]
CO₂/乙醇CO₂/ thanol	碳毡 Carbon felt	Acetobacterium、Clostridium spp.	丁酸、己酸和庚酸Butyrate, caproate, and heptanoate	80.3	2.41	7.7	<1	[45]
乙酸 acetate	石墨毡 Graphite felt	Clostridium kluyveri	丁酸、己酸和辛酸Butyrate, caproate, and caprylate	26.0	0.19	0.8	-	[40]
乙酸/乙醇 acetate / ethanol	无极电 Without electrode	Acetoanaerobium、Dysgonomonas、Clostridium spp.	丁酸、己酸Butyrate, and caproate	60.0	3.40	10.0	1	[46]
甘油glycerol	石墨板 Graphite plate	Citrobacter、Pectinatus、lostridium spp.	丙酸和戊酸Propionate, and valerate	-	-	-	-	[8]
甘油glycerol	石墨板 Graphite plate	Citrobacter、Pectinatus、Clostridium spp.	乙酸、丙酸和丁酸Acetate, ropionate, and butyrate	-	-	-	-	[47]