Characterising the mechanism of abating biogenic amines accumulation by cocultures of Zygosaccharomyces rouxii and Tetragenococcus halophilus

In this study, we optimised the abatement of BAs accumulation during soy sauce fermentation and investigated the underlying mechanism. Tetragenococcus halophilus and Zygosaccharomyces rouxii isolates were screened from moromi based on their decarboxylase activity, acid production, and BAs-degrading ability. We found that cocultures of a T. halophilus isolate and a Z. rouxii isolate inhibited the formation of putrescine and cadaverine, leading to a reduction in the BAs content (52.36–55.05%). However, this efficiency of abatement significantly decreased, while BAs concentration increased when cocultures of other isolates were used. This was attributed to acid-stress response, community diversity, and interspecific interaction between the different communities. The positive correlation between T. halophilus and Z. rouxii was beneficial to abate BAs accumulation. PICRUSt2 analysis results showed that the abundance of BAs degradation enzymes was upregulated in bacteria but downregulated in fungi. Our study provides insights into the mechanism underlying the enhanced abatement of BAs accumulation by cocultures of T. halophilus and Z. rouxii.