一株猪粪降解菌的筛选、评价及鉴定

发酵床是目前国内规模化养猪企业广泛采用的粪污处理模式,其关键在于投加的微生物菌剂。为了分离出能高效降解猪粪的菌株,采用NH₃选择性培养基对土壤微生物菌株进行初筛,共得到7株氨氮降解率大于70%的菌株。通过猪粪发酵模拟实验对分离株的NH₃抑制效果进行初步评价,结果表明,7株菌株均能不同程度地减少猪粪发酵过程中氨的释放量,其中Z10菌株的NH₃抑制效果最为显著。针对猪粪除臭及促进猪粪腐熟效果开展了Z10菌株应用效果评价。除臭试验结果显示,Z10菌株对猪粪臭气中NH₃与H₂S均有较好的抑制作用,在21 d发酵周期内, NH₃与H₂S的释放量较对照组分别减少了38.66%与50.03%。促腐熟试验结果显示,Z10组种子发芽率与发芽指数分别达到了83.33%与88.55%,而对照组发芽率与发芽指数仅为68.35%与59.12%。生化鉴定显示,Z10菌株无蛋白酶活性,具有较弱的糖化酶、淀粉酶及脂肪酶的活性,但表现出较强纤维素降解活力,其纤维素酶活力达到232.543 U·mL^-1,推测Z10菌株表现出的促腐熟效果主要源于其高纤维素降解活力。16S rDNA分子鉴定结果显示该菌为烟曲霉菌(Aspergillus fumigatus)。

Screening,evaluation and identification of a pig manure decomposing strain

Fermentation bed is a kind of manure treatment mode widely used by domestic large-scale pig raising enterprises at present while the key technology is microbial inoculum. To isolate strains which can efficiently degrade pig manure, ammonia selective medium was used to screen soil microbial strains, and 7 strains with ammonia nitrogen degradation rate over 70% were obtained. The ammonia inhibition effects of the 7 strains were preliminarily evaluated through pig manure fermentation simulation experiments. The results showed that the 7 strains could reduce ammonia release in pig manure fermentation process to varying degrees, and Z10 strain had the most significant ammonia inhibition effect. The application effect of Z10 strain was evaluated for deodorization of pig manure and promotion of pig manure decomposition. Deodorization experiment results showed that Z10 strain had a good inhibitory effect on NH₃ and H₂S in pig manure odor. During the 21-day fermentation period, compared with the control group, the release of NH₃ and H₂S decreased by 38.66% and 50.03%, respectively. The results of maturity promotion experiment showed that the germination rate and germination index of Z10 group reached 83.33% and 88.55% respectively, while the germination rate and germination index of control group were only 68.35% and 59.12%. Biochemical identification showed that Z10 strain had no protease activity, weak saccharifying enzyme and amylase and lipase activities, but showed strong cellulose degradation activity, and its cellulase activity reached 232.543 U·mL^-1. It was speculated that the decomposition effect of Z10 strain was mainly due to its high cellulose degradation activity. 16S rDNA molecular identification showed that the bacterium was Aspergillus fumigatus.