A new strategy for lactate inhibiting odor emission from pig manure based on microbial symbiotic network regulation

The pigsty is a major source of odor emissions, and effective on-site odor control is essential for improving the growth environment of pigs and reducing the burden on downstream deodorization systems. In this study, a simulated pigsty environment was used to systematically evaluate the deodorization efficacy of five organic acid salt solutions applied via surface spraying on pig manure. The objectives were to clarify their physicochemical solubilization effects, underlying microbial mechanisms and key functional taxa. Results showed that sodium lactate significantly outperformed the other organic acid salts, achieving an average reduction of 34.4 % ± 19.4 % in total odor activity over a 48-h cleaning period. This superior performance was primarily due to the effective inhibition of the key odorant p -cresol, with an average removal rate of 42.5 % ± 23.6 % and a peak removal rate of 76.8 % ± 1.2 % at 48 h. Analyses of the critical micelle concentration and Henry's law constant ruled out solubilization as the primary mechanism of p -cresol removal. Furthermore, changes in microbial biomass did not support the hypothesis that lactate deodorizes mainly via broad-spectrum bacterial inhibition. Instead, the primary mechanism involves enhanced microbial degradation of p-cresol. Notably, the biomass of the key bacterial genus Lentilactobacillus increased by 8.1–217.9-fold, promoting a microbial community that includes Faecalibaculum , Bifidobacterium , and Lachnospiraceae NK4A136_group . This community disrupts the stability of the odor-producing microbial symbiotic network through negative interactions. This study provides a new solution for controlling odor emissions from pig manure by identifying key microbial symbiotic mechanisms involved in odor production and inhibition.