Deodorizing microorganisms: screening and application in composting

Abstract:

[Objective] To isolate the microorganisms that can remove ammonia and hydrogen sulfide from biogas residue and pyrite soil and use them for composting, so as to reduce the odor release in the process of manure treatment and improve the working environment. [Methods] The microorganisms capable of removing ammonia and hydrogen sulfide were screened out by the culture method and identified by 16S rRNA gene sequencing. The strains with good removal performance were selected to prepare the microbial deodorants. The deodorants were then applied to the composting of manure, and their deodorization effects were preliminarily evaluated based on the concentrations of ammonia and hydrogen sulfide. [Results] A total of 12 ammonia-removing strains and 5 sulfur-removing strains were isolated, from which 5 strains with good removal performance were screened out and labeled as N-2, N-5, N-6, N-11, and S-3, respectively. The microbial deodorant composed of strains N-5, N-6, N-11, and S-3 had the best deodorization effect, with the ammonia- and sulfide-removing rates of 82.46% and 84.84%, respectively. The composting test proved that the microbial deodorant had deodorization effect. Especially in the early stage of composting, the microbial deodorant group reduced the release of ammonia and hydrogen sulfide in the process of turning on day 7 by 62.84% and 53.12%, respectively, compared with the control group. At the end of composting, the ammonia nitrogen content of the microbial deodorant group was 33.62% lower than that of the control group. [Conclusion] The microbial deodorant produced in this study can effectively reduce the release of odorant gas in the process of manure composting and thus demonstrates great application potential in improving the environment of livestock waste treatment.