Screening and application of degraded ethyl carbamate yeast in the brewing microecology of Zhimaxiangxing baijiu

Ethyl carbamate (EC) is an endogenous pollutant in traditional fermented foods and has potential carcinogenicity. In this work, a yeast capable of degrading EC was screened from the microecology of Zhimaxiangxing baijiu (ZB). The strain, which exhibited excellent fermentation performance and strong resistance to acids and ethanol, was identified as Pichia manshurica and named Pichia manshurica AHXJ-p4 by homologous alignment analysis of its ITS gene sequence. Then its optimised solid-state fermentation (SSF) culture conditions were determined as follows: the addition ratio of wheat bran to corn meal ranged from 4.6:0.9 to 4.8:0.7 (w/w), the water content was 55% (w/w), the inoculation amount was 10% (v/v), and the pH was 5.0. This study expanded the research on the application of yeast in baijiu brewing and provided a theoretical basis for establishing a production process for Fuqu with an EC-reducing function. Furthermore, this work is significant for enhancing the quality of the baijiu industry and controlling food safety.