Screening of skatole-degrading bacteria and control of human fecal odor by compound bacteria

Purpose The biodegradation of skatole was used as a starting point in this study, and existing strains of degrading NH 3 and H 2 S in the laboratory were combined to create a composite deodorant. The deodorization effect of the composite deodorant on human feces was investigated in order to provide a foundation for fecal odor gas treatment. Methods Skatole-degrading bacteria were identified, degradation conditions were optimized, and skatole metabolites were identified using liquid chromatography-mass spectrometry (LC-MS). The skatole-degrading bacteria were combined with the existing strains of degrading NH 3 and H 2 S in the laboratory to make a compound deodorizer, and the deodorizing effect of the compound deodorizer on fresh human feces and old human feces was compared. Liquid chromatography, specific sensors, and gas chromatography were used to determine the contents of skatole, NH 3 , H 2 S, and volatile organic compounds, and the microbial diversity was examined. Results Microbial agents H and Y capable of utilizing skatole were screened out under aerobic and facultative anaerobic conditions, respectively. Within 48 h, the degradation rate of skatole by microbial agent Y was 88.52%. Following condition optimization, the optimum temperature for skatole degradation by microbial agent Y was 33 °C, and the optimum pH was 7. The main functional bacteria were Acinetobacter xiamenensis . The metabolites of skatole were determined by liquid chromatography-mass spectrometry (LC–MS), and six possible metabolites were found, including 3-aldehyde indole, 3-carboxyl indole, 1H-indole-2,3-dione, and 3-methyl indole pyruvate. The skatole-degrading bacteria Lactobacillus rhamnosus and Saccharomyces cerevisiae were then combined in proportion to form a composite deodorant. The 5-day degradation rate of skatole in the old manure group was 88.11%, while the 5-day degradation rate in the fresh manure group was 47.56%. Conclusions The compound microbial agent developed in this study has a solid deodorizing effect, particularly in the control of the odor of obsolete feces. The use of composite microbial agents can efficiently degrade skatole in human feces, providing a theoretical foundation for the use of microbial remediation in the actual world. Graphical Abstract