The influence of sauerkraut fermentation wastewater on nitrogen retention during the composting of garden waste: Focusing on the regulation of the abundance of core microorganisms in the cooling stage

This study evaluated the effects of adding sauerkraut fermentation wastewater on nitrogen loss and the composting process of garden waste. The addition of 1 % sauerkraut fermentation wastewater affected microbial community in the Micro-environmental Control System (MECS) protection box. It increased the number of bacteria positively correlated with the TON and NO₃^--N components, increased the number of bacteria highly positively correlated with nitrification, and decreased the number of bacteria positively correlated with denitrification. Moreover, it modulated core microbial abundance in the cooling stage, thus it significantly increased the relative abundance of the nitrifying bacteria Bacillus, Lysinibacillus, and Oceanobacillus. Analysis of nitrogen cycling genes revealed that sauerkraut fermentation wastewater enhanced nitrification and suppressed denitrification, thus mitigating nitrogen loss. This study provided a new strategy for the treatment of wastewater and an important scientific basis for reducing environmental pollution.