木质纤维素类废弃物固态厌氧发酵降解机制及微生物协同代谢解析

Solid-state anaerobic digestion (SS-AD) has gained increasing attention in recent years, especially for digesting lignocellulosic biomass. SS-AD has been claimed to be advantageous over liquid anaerobic digestion for a number of reasons including high volumetric methane productivity, small reactor volume, low energy requirements for heating, and minimal material handling. Besides, for lignocellulosic biomass, SS-AD can solve the problems of floating and layering. However, due to the low biodegradability of lignocellulosic biomass and lack of understanding on degradation mechanism and microbial metabolism analysis, the utilization and innovation of SS-AD technology is faced with lots of challenges. In this research, mechanical and biological pretreatments are used for enhancing the biodegradability of lignocellulosic biomass. Then, we try to find the balanced relationship between pretreatment efficiency and biogas production performance of SS-AD. The degradation mechanism of lignocellulosic biomass is studied by combining biogas production, bioaugmentation, domestication, real-time quantitative PCR, and high-throughput sequencing technology. The acetogens and methanogens in methanation phase are quantitatively analyzed by Miseq sequencing technology and bioinformatics methods. On this basis, we try to build a mass transfer-degradation dynamics model. This research will help to understand the SS-AD system from macro to micro, and provide theoretical basis and technical support for the application of SS-AD technology.

固态厌氧发酵技术近些年来受到广泛关注，特别是在处理木质纤维素类废弃物方面。与液态发酵相比，固态发酵具有反应体积小、负荷高、需水量少、设计简便等优点，同时可解决木质纤维素类原料上浮、结壳和分层等问题。然而，由于此类原料可生物降解性差，以及人们对固态发酵原料降解机制的不了解和对微生物代谢认识不够，限制了该技术使用和改进。本研究结合原料及固态厌氧发酵的特点，采用机械与生物预处理提高原料可生物降解性，并研究预处理程度和固态发酵产气性能间的平衡关系，结合生物强化、菌种驯化、生物信息学及高通量测序技术，探究木质纤维素类废弃物固态厌氧发酵降解机制；运用微生物学和分子生物学分析系统内不同时空分布下微生物种群结构和优势菌种，对发酵体系内产酸菌和产甲烷菌的动态变化进行定性和定量解析；建立传质——降解动力学模型，阐明木质纤维素类废弃物和微生物体系中的传质及生化反应机理，为该工艺的应用提供理论基础和技术支持。

固态（干式）厌氧消化技术近些年来受到广泛关注，特别是在处理木质纤维类废弃物方面。与液态（湿式）厌氧消化相比，固态厌氧消化具有反应体积小、负荷高、需水量少、设计简便等优点，同时可解决木质纤维类原料上浮、结壳和分层等问题。然而，由于此类原料可生物降解性差，以及人们对固态消化过程中原料降解机制的不了解和对微生物代谢认识不够，限制了该技术的使用和改进。本研究结合原料及固态厌氧消化的特点，采用机械与生物预处理提高原料可生物降解性，并结合菌种驯化、渗滤液喷淋策略和高通量测序技术，探究木质纤维类原料固态厌氧消化降解机制；运用微生物学和分子生物学分析系统内不同时空分布下微生物种群结构和优势菌种，对发酵体系内关键菌群的动态变化进行定性和定量解析，并分析生物和非生物因素对固态厌氧消化产气的影响；采用扩散分布模型，分析固态厌氧消化过程中动力学参数（水解速率常数、乙酸转化系数、乙酸最大利用率和微生物衰减系数）变化规律，为该工艺的应用提供理论基础和技术支持。