Preliminary study on the application of Stenotrophomonas terrae in the remediation of degraded pit mud

In order to repair degraded pit mud, the Stenotrophomonas terrae was inoculated to the degraded pit mud, with normal pit mud and degraded pit mud as the control, the physicochemical indexes and bacterial flora of pit mud, fermented grains and Baijiu samples after fermentation were detected, and principal coordinate analysis (PCoA) and correlation network analysis were carried out for bacterial flora of different pit mud samples. The results showed that the pH, acid-producing capacity, ammonium nitrogen content and sensory scores of the repaired pit mud were significantly increased to 4.82, 185.83 mg/g, 98.33 mg/100 g, and 6.10 (P<0.05). The acidity of the corresponding fermented grains was significantly decreased to 3.27 (P<0.05). There were no significant differences in moisture and residual starch contents (P>0.05). The contents of total esters and ethyl caproate in corresponding Baijiu samples were significantly improved to 1.00 g/L and 0.56 g/L (P<0.05), and the total acid was significantly decreased from 0.49 g/L to 0.27 g/L (P<0.05). The bacterial flora richness and diversity of repaired mud increased. Based on genus level, the relative abundance of Lactobacillus decreased significantly (P<0.01). The relative abundance of functional microorganisms of Hydrogenispora, Clostridium_sensu_stricto_12, Alkalibaculum and Caproiciproducens significantly increased (P<0.01). PCoA and correlation network analysis showed that after inoculation with S. terrae, the microbial flora could be close to that of normal pit mud, which could enhance the synergistic effect among bacterial in pit mud and improve the stability of microbial ecological network.