Effects of microbial deodorizer on pig feces fermentation and the underlying deodorizing mechanism.

Microbial deodorization is a novel strategy for reducing odor in livestock and poultry feces. Herein, 12 strains of ammonia (NH) and 15 hydrogen sulfide (HS) removing bacteria were obtained with a removal efficiency of 65.20-79.80% and 34.90-79.70%, respectively. A novel bacteria deodorant named MIX (Bacillus zhangzhouensis, Bacillus altitudinis, and Acinetobacter pittii at a ratio of 1:1:2) were obtained. MIX can shorten the temperature rising stage by 2 days and prolong the thermophilic stage by 4 days. The ability of MIX to remove NH, HS, and volatile fatty acids (VFAs) and the underlying removal mechanism were analyzed during pig feces fermentation. MIX can significantly reduce the concentrations of NH and HS by 41.82% and 66.35% and increase the concentrations of NO-N and SO by 7.80% and 8.83% (P < 0.05), respectively, on the 25th day. Moreover, the concentrations of acetic, propionate, iso-valerate, and valerate were significantly reduced. The dominant bacteria communities at the phylum level were Firmicutes, Proteobacteria, Bacteroidetes, and Spirochaetes. B. zhangzhouensis and B. altitudinis could convert NH-N to NO-N, and A. pittii could transfer HS to SO. This study revealed that bacteria deodorant can reduce the concentrations of NH, HS, and VFAs in pig feces and increase those of NH, NO, and SO and has excellent potential in deodorizing livestock and poultry feces composting.