[Screening and nitrogen transformation activity of ammonia-oxidizing molds during aerobic chicken manure composting].
ABSTRACT In order to explicit the existence and nitrogen transformation activity of ammonia-oxidizing molds during aerobic chicken manure composting, the medium of ammonia-oxidizing molds was used to screen them, and correlation analysis between mycelium biomass and nitrogen transformation indexes was conducted, then high-effective ammonia-oxidizing strains were determined and added into aerobic compost. The results show that all tested strains are able to oxidize ammonium nitrogen to nitrite nitrogen and nitrate nitrogen, indicating that there are plenty of ammonia-oxidizing molds during aerobic chicken manure composting. Significantly positive correlations are detected between total contents of nitrite nitrogen and nitrate nitrogen, mycelium biomass and mycelium Kjeldahl nitrogen. When cultured in the medium of ammonia-oxidizing molds for 144 hours, two high-effective ammonia-oxidizing strains, named M25-22 (Penicillium sp.) and M40-4 (Aspergillus sp.), produce nitrate nitrogen by 1.1 x 10(-3) mg x mL(-1), 1.5 x 10(-3) mg x mL(-1), respectively, and decrease ammonium nitrogen by approximately 0.3 mg x mL(-1). Compared with the control treatment, the composting treatment with microbial agent M25-22 or M40-4 has lower ammonium nitrogen content, and higher contents of nitrate nitrogen and total nitrogen, indicating that they are of practical significance in reducing nitrogen loss during aerobic composting.