研究报告
何琴,李蕾,赵小飞,伍迪,彭绪亚.餐厨垃圾厌氧消化过酸化系统微生态特征的宏基因组学分析[J].环境科学学报,2022,42(10):374-384
餐厨垃圾厌氧消化过酸化系统微生态特征的宏基因组学分析
- Metagenomic analysis of microbial characteristics in over-acidification systems during anaerobic digestion of food waste
- 基金项目：国家自然科学基金（No.51808450）；西华师范大学博士启动基金（No.18Q029）；重庆市自然科学基金（No.cstc2018jcyjAX0743）
- 作者
- 单位
- 何琴
- 重庆大学三峡库区生态环境教育部重点实验室，重庆 400045;西华师范大学环境科学与工程学院，南充 637002
- 李蕾
- 重庆大学三峡库区生态环境教育部重点实验室，重庆 400045
- 赵小飞
- 重庆交通大学河海学院，重庆 400066
- 伍迪
- 重庆大学三峡库区生态环境教育部重点实验室，重庆 400045
- 彭绪亚
- 重庆大学三峡库区生态环境教育部重点实验室，重庆 400045
- 摘要：过酸化失稳是困扰有机废物厌氧消化（AD）过程高效稳定运行的一大难题.为探析不同诱导方式造成过酸化的AD系统微生态特征差异，在餐厨垃圾中温AD反应器中分别引入负荷扰动（R2）、温度及搅拌扰动（R3）以诱发系统过酸化，利用宏基因组学测序技术，对比考察稳定与酸化系统微生物群落结构及主要产甲烷功能路径差异.结果表明，两种方式均成功诱发系统过酸化失稳，过酸化系统中挥发性脂肪酸（VFA）过量富集（R2、R3系统中分别高达（12.53±1.96） g·L-1和（8.00±0.81） g·L-1）的同时，丙酸等多碳VFA组分比例大幅升高.R2、R3系统酸化后其产甲烷菌及相关酶受到高浓度VFA的显著抑制，酸积累程度更高的R2受抑制更为明显.且经相关性分析发现，多碳酸尤其是丙酸是抑制产甲烷作用的关键因素.与R2相比，R3具有更高的耗氢能力，耗氢微生物如可耗H2产酸的Treponema属和氢营养型产甲烷菌Methanoculleus属、Methanospirillum属等相对丰度显著高于R2.酸化系统均以乙酸营养型产甲烷为主要的产甲烷途径，并以Methanosaeta属为主要的乙酸型产甲烷菌.酸化系统中更高含量的乙酸产甲烷途径的AK-PTA酶有利于促进对乙酸的利用，增强厌氧消化微生物菌群对高浓度乙酸的耐受 能力.本研究中的相关结果可为提高有机废物AD微生态抗酸化能力提供理论依据和数据支撑.
- Abstract：Over-acidification is a major problem that disrupts the efficient and stable operation of organic waste anaerobic digestion （AD）. In order to explore the differences of microecological characteristic in over-acidification AD systems induced by different methods， load disturbance （R2）， temperature and stirring disturbance （R3） were introduced into mesophilic anaerobic digesters for food waste. The metagenomics sequencing technology was employed to compare the differences of microbial community structure and main methanogenic pathways of stable and over-acidification systems. The results showed that system instability caused by over-acidification occurred in both R2 and R3 systems. In the over-acidification AD systems， volatile fatty acids （VFA） were excessively enriched （（12.53±1.96） g·L-1 for R2 and （8.00±0.81） g·L-1 for R3， respectively）， meanwhile the proportion of multi-carbon VFA components such as propionic acid increased significantly. After over-acidification， methanogens and the related enzymes were significantly inhibited by high concentration of VFA in both R2 and R3 systems， moreover the R2 system showed a higher inhibition phenomenon due to its higher acid accumulation. The result of correlation analysis indicated multi-carbon VFA， especially propionic acid， was the key factor to inhibit methanogenesis. Compared with R2， the microbial community in R3 showed a higher hydrogen consumption capacity. The relative abundance of hydrogen consuming microorganisms in R3 such as Treponema， which can consume H2 to produce acid， and hydrogenotrophic methanogens （Methanoculleus and Methanospirillum） were significantly higher than that of the R2. In both of the over-acidification systems， acetotrophic methanogenesis was the primary methanogenic pathway and Methanosaeta as the main acetotrophic methanogens. The higher content of AK-PTA enzymes for the acetotrophic methanogenesis in the acidification system can promote the utilization of acetic acid and enhance the tolerance of anaerobic digestion microbiota to high concentration of acetic acid. The above results in the present study may provide theoretical basis and data support for improving the acid resistant capability of microbial community in anaerobic digestion system.
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