Reduction of ethyl carbamate in soy sauce by Bacillus amyloliquefaciens mutants

Abstract:

[Objective] To prepare mutants of Bacillus amyloliquefaciens JY06 stain with enhanced arginine consumption capability to reduce carcinogenic compound ethyl carbamate and its precursors in soy sauce.[Methods] Atmospheric and room temperature plasma (ARTP) and UV mutagenesis were used to mutate Bacillus amyloliquefaciens JY06, and a high-throughput screening approach was used to characterize mutants with high arginine utilization capability. The properties of mutants were studied following addition to soy sauce moromi during fermentation to initiate reduction of citrulline and ethyl carbamate.[Results] Twelve mutants with elevated arginine utilizing ability were obtained through ARTP and UV mutagenesis, of which C12 and E6 displayed the highest capacity for eliminating EC and citrulline. Compared with the JY06 parent strain, the addition of C12 or E6 to the moromi during soy sauce fermentation decreased citrulline content in soy sauce by 15.6% and 14.7%, and reduced ethyl carbamate by 19.3% and 13.1%, respectively.[Conclusion] Both ethyl carbamate and its precursor citrulline were significantly decreased in soy sauce by B. amyloliquefaciens JY06 mutants in the moromi during fermentation, demonstrating the potential of the mutants to control or eliminate toxic compounds in soy sauce and similar food products.

Key words:soy sauce;ethyl carbamate;citrulline;Bacillus amyloliquefaciens;mutagenesis