Abstract: 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.

Key words: strain screening, deodorization, pig manure maturation, Aspergillus fumigatus