藻酸盐降解菌群强化剩余污泥厌氧消化产甲烷

厌氧消化生产甲烷是实现剩余污泥(WAS)资源化的重要技术,水解阶段是WAS厌氧资源化的限速步骤。WAS中的酸性多糖(如藻酸盐和半乳糖醛酸等)能够与水中Ca2+等二价阳离子形成凝胶类物质,具有维持污泥结构并阻碍微生物水解的作用,被认为是结构性胞外聚合物的主要组分。首先利用藻酸盐为底物经过恒化器培养得到高活性的藻酸盐降解菌群(ADC)。结果表明:投加ADC菌群能够明显提高剩余污泥(WAS)厌氧消化的功能,即在接种比［m(ADC)∶m(VSS)］为0.03 g/g时,污泥的甲烷产量提高了53.6%。进一步分析表明,该菌群对WAS的几种典型有机成分(聚半乳糖醛酸、葡聚糖和酪蛋白等)均具有较好的厌氧降解能力。Illumina Miseq高通量测序结果表明该ADC菌群以拟杆菌属(Bacteroides,96.3%)为主。该成果为强化剩余污泥厌氧发酵产甲烷提供了一种新的微生物方法。

ENHANCED METHANOGENESIS OF WASTE ACTIVATED SLUDGE FERMENTATION BY DOSING AN ALGINATE-DEGRADING CONSORTIUM

Methane production by anaerobic digestion is popular biotechnology to utilize the wanted waste activated sludge (WAS). But the hydrolysis is known as the rate-limiting step of WAS fermentation. The uronic acids (such as alginate and polygalacturonic acid) in WAS can form hydrogels with cationic ions (i.e. Ca2+) in wastewater, which can maintain sludge structure and retard the microbial hydrolysis. Thus, these organics are deemed as the main components of structural extracellular polymeric substances. In this work, an alginate-degrading consortium (ADC) with high activity was enriched in a mesophilic chemostat using alginate as the substrate. The results showed that the enriched ADC could notably enhance methane production from WAS. The methane yield increased by 53.6% under a low ratio of inoculum to WAS of 0.03 g/g m(ADC)∶m(VSS)]. Moreover, the typical organic components of WAS, including polygalacturonic acid, dextran, and casein, could be utilized by the enriched ADC. The genus Bacteroides (96.3%) was identified as the dominant bacteria in ADC by an Illumina Miseq high-throughput sequencing. Therefore, this work provided a new microbial method for biochemical production in WAS.