纳米CaO_(2)促进污泥厌氧发酵产酸性能的微生物机制  

Effects and Mechanism of Nano-CaO_(2) on Acid Production in Anaerobic Sludge Fermentation

作　　者：潘禹 刘鲡 智笑涵 朱洪涛[1,2] PAN Yu;LIU Li;ZHI Xiaohan;ZHU Hongtao(Beijing Key Lab for Source Control Technology of Water Pollution,Beijing Forestry University,Beijing 100083,China;College of Environmental Science and Engineering,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学,北京市水污染源头控制技术重点实验室,北京100083 [2]北京林业大学环境科学与工程学院,北京100083

出　　处：《环境科学研究》2023年第7期1426-1434,共9页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.52270117,51878046)。

摘　　要：过氧化钙(Calcium peroxide,CaO_(2))可大幅促进污泥厌氧发酵产酸,但其对微生物群类转换的影响机制暂不明晰.针对这一问题,开展了不同CaO_(2)投加比例(每g污泥挥发性固体中CaO_(2)投加量分别0、0.10、0.15、0.20、0.25、0.30、0.35 g,依次标记为C-0、C-10、C-15、C-20、C-25、C-30、C-35)下的污泥厌氧发酵研究,并从胞外聚合物、抗氧化酶等角度解析CaO_(2)氧化胁迫下剩余污泥厌氧发酵产酸微生物群落变化的机制.结果表明:①CaO_(2)促进了污泥的水解,C-35组发酵效果最好,产物短链脂肪酸(short chain fatty acids,SCFAs)的浓度达到1424 mg/L,约为C-0组的4.3倍.②高通量测序结果表明,投加CaO2会降低微生物群落的多样性,富集水解产酸菌,抑制其他门类细菌.其中厚壁菌门的相对丰度从C-0组的7.16%增至C-35组的64.23%,产SCFAs的梭菌纲和芽孢杆菌纲相对丰度也显著增加.③随着CaO_(2)投加比例增加,细菌胞外聚合物(extracellular polymeric substances,EPS)由紧密结合型向松散结合型和黏液型转化,并促进了细菌胞外多糖的合成与分泌,提高了功能菌群的生存能力.④细菌的抗氧化酶系统对厌氧发酵体系中功能菌群的筛选可能具有影响.CaO_(2)提高了功能菌群的超氧化物歧化酶和过氧化氢酶基因的相对丰度,从而可通过促进抗氧化酶的分泌,提高功能菌群的抗氧化能力,使细菌群落向有利于生产SCFAs的菌群转化.研究显示,在CaO_(2)氧化胁迫下,功能菌群会通过促进EPS的分泌与转化来提高抗氧化酶活性,增强自身的抗氧化能力,从而促进微生物群落中水解酸化功能菌群的富集,这正是该工艺方法提高SCFAs产量的微生物机制.Calcium peroxide(CaO_(2))can enhance acid production in sludge anaerobic fermentation.However,the mechanism of microbial community change under different CaO_(2) content is still unclear.To clarify this,the anaerobic fermentation of sludge was studied under different CaO_(2) dosage ratios(the dosage ratio of CaO_(2) per gram of sludge volatile solids were 0,0.10,0.15,0.20,0.25,0.30,0.35,respectively,labeled as C-0,C-10,C-15,C-20,C-25,C-30,C-35)and the microbial mechanisms were analyzed by measuring bacterial extracellular polymer substances(EPS)and antioxidant enzymes.The experimental results show that:(1)CaO_(2) promoted the hydrolysis of sludge.The fermentation performance of C-35 group is the best.The production of short chain fatty acids(SCFAs)reached 1424 mg/L,about 4.3 times that of the C-0 group.(2)The results of high-throughput sequencing showed that CaO_(2) decreased the diversity of microbial communities,enriched acidogenic bacteria and inhibited other bacteria.The relative abundance of Firmicutes increased from 7.16% in the C-0 group to 64.23% in the C-35 group.The significant increase in the abundance of Clostridia and Bacilli was the main reason for the high yield of SCFAs in this group.(3)With the increase of CaO_(2) dosage ratio,EPS transformed from tightly bounded EPS to loosely bounded EPS and slime EPS,which promoted the synthesis and secretion of bacterial extracellular polysaccharide and improved the viability of functional bacteria.(4)Bacterial antioxidant enzymes also affected the changes in functional bacteria communities in anaerobic fermentation systems.The addition of CaO_(2) increased the relative abundance of SOD and CAT related genes,improved the antioxidant capacity of functional bacteria by promoting the secretion of antioxidant enzymes,and enhanced the production of SCFAs.The results showed under CaO_(2) oxidative stress,the functional bacterial community enhances its antioxidant capacity by promoting the secretion and transformation of EPS and increasing antioxidant enzyme activit

关 键 词：厌氧发酵 剩余污泥 短链脂肪酸(SCFAs) 抗氧化酶 胞外聚合物(EPS) 微生物 

分 类 号：X741[环境科学与工程—环境工程]