碱性蛋白酶与烷基糖苷协同促进剩余污泥厌氧发酵产酸

The production of short-chain fatty acids from waste activated sludge anaerobic fermentation by combining alkaline protease with alkyl polyglucose

针对剩余污泥厌氧发酵产短链脂肪酸(SCFAs)面临的污泥水解效率低的问题,将碱性蛋白酶(AP)与烷基糖苷(APG)联合用于污泥厌氧发酵产酸中。结果表明,AP与APG在强化污泥厌氧发酵产SCFAs过程中具有协同作用,在9%g AP/g SS和0.20 g APG/g SS的作用下,在厌氧发酵第3 d取得的最大SCFAs产率为214.80 mg COD/g VSS,显著高于两者单独作用时,且以乙酸为主。AP与APG的协同作用提高了污泥增溶与水解效率,改善了污泥发酵液的生物可降解性能,为酸化阶段提供了良好的发酵底物。同时,蛋白酶、α-葡萄糖苷酶、乙酸激酶的活性得到提高。微生物群落结构分析表明,AP与APG的协同作用提高了Firmicutes、Bacteroidetes和Actinobacteriota等水解酸化类微生物的相对丰度,而Proteobacteria和Cloroflexi等消耗SCFAs的微生物的相对丰度显著降低。

Anaerobic fermentation is an prominent approach for carbon resource recovery from waste activated sludge,obtaining short-chain fatty acids(SCFAs),which was limited by the low sludge hydrolysis efficiency.An efficient strategy was put up for SCFA production from sludge anaerobic fermentation by the combination of alkaline protease(AP)and alkyl polyglucose(APG).Results revealed the synergetic effect of AP and APG towards the enhancements of SCFA generation,and the maximum SCFA yield of 214.80 mg COD/g VSS was achievable within 3 d at 9%g AP/g suspended solids(SS)and 0.20 g APG/g SS,which was much higher than those of their individuals.Acetic acid was the predominant individual SCFA.The promotion of SCFA accumulation by the synergetic effect of AP and APG was attributed to the acceleration of solubilization and hydrolysis,which improved the biodegradability of fermentation liquid,providing a preferable substrate for acidification.Meanwhile,the activities of protease,α-glucosidase and acetate kinase were greatly stimulated.Microbial community analysis indicated that the relative abundance of bacteria responsible for hydrolysis and acidification,such as Firmicutes,Bacteroidetes and Actinobacteriota,was enriched by the combining of AP and APG,whereas the relative abundance of bacteria consuming SCFAs,such as Proteobacteria and Cloroflexi,was seriously decreased.