接种污泥和pH值对CMC-Na厌氧降解的影响及菌群解析

Effect of inoculated sludge and pH on the anaerobic degradation of sodium carboxymethyl cellulose as well as microbial community analysis

为揭示羧甲基纤维素钠(CMC-Na)的厌氧降解效率,本研究采用间歇培养方式考察了不同类型接种污泥和初始pH值对其厌氧降解的影响,并通过Illumina MiSeq测序揭示了主要功能微生物对初始pH值的响应特征.结果表明,在CMC-Na初始浓度为5g/L条件下,絮状污泥具有较强的水解、发酵产酸能力.但该系统的产氢产乙酸作用和产甲烷作用较差,导致甲烷产率仅为10.0mL/g CMC-Na.相反,颗粒污泥具有较高的甲烷发酵能力,甲烷产率达到了100.2mL/g CMC-Na.初始pH值对CMC-Na厌氧降解影响试验表明,初始pH 4.5和9.5对甲烷生成表现出明显的抑制作用,而在初始pH 7.5和8.5条件下,甲烷产率达到了最大值(123.4和123.2mL/g CMC-Na).Illumina MiSeq测序结果表明,不同初始pH值环境中的微生物组成存在显著差异.在初始pH 7.5条件下,Methanothrix和Methanobacterium为优势产甲烷菌,而Macellibacteroides,Petrimonas,Trichococcus,Anaerofilum和Brooklawnia为优势产酸发酵菌.当初始pH值为4.5和9.5时,Methanosarcina也成为优势产甲烷菌,且主要产酸发酵菌的相对丰度发生了明显变化.

In order to reveal the anaerobic degradation efficiency of sodium carboxymethyl cellulose(CMC-Na),the effects of different types of inoculation sludge and initial pH on the anaerobic degradation of CMC-Na were investigated by batch culture.The response of microbial community on initial pH was revealed by Illumina MiSeq sequencing.The results showed that the flocculent sludge had strong hydrolysis and fermentation acid-producing capacity under the initial CMC-Na concentration of 5g/L condition.However,this system was unfavorable for syntrophic acetogenesis and methanogenesis,resulting in the methane yield was reached 10.0mL/g CMC-Na.On the contrary,the high methane fermentation capacity of the granular sludge made the methane yield reached 100.2mL/g CMC-Na.The effects of initial pH on anaerobic degradation of CMC-Na showed that the methane production was significantly inhibited by initial pH 4.5 and 9.5.However,the methane yield reached the maximum(123.4 and 123.2mL/g CMC-Na)at the initial pH 7.5 and 8.5.Illumina MiSeq sequencing showed that the microbial composition in different initial pH conditions was significantly different.At initial pH 7.5,Metanothrix and Metanobacterium were the dominant methanogens,while Macellibacteroides,Petromonas,Trichococcus,Anaerofilum and Brooklawnia were the dominant fermentation acid-producing bacteria.When the initial pH was 4.5 or 9.5,Metanosarcina also became a dominant genus,and the relative abundance of the main fermentation acid-producing bacteria was changed significantly.