Identification of an alcohol tolerant multicopper oxidase for reduction of biogenic amines in fermented foods

Abstract

Biogenic amines are a group of microbial metabolites detected in fermented foods that have potential health risk. Reduction of biogenic amines in fermented foods by enzymes is an effective and safe approach as it has less influences on food flavor and fermentation process. In this work, a multicopper oxidase named as MCOP from Lactobacillus paracasei XJ02 was successfully expressed in E. coli BL21 (DE3). The K _m and V _max of MCOP were detected to be 4.34 mmol/L and 5.61 mmol/ (L· min), respectively. MCOP was resistant to acidic condition and was stable at a wide temperature range (4^oC−65^oC). Activity of MCOP was significantly inhibited by 5−20% NaCl, whereas it was dramatically increased in the presence of 5−20% ethanol. This enzyme significantly degraded putrescine and cadaverine in soy sauce with a degradation rate of 10.3% of total BAs. Moreover, addition of MCOP efficiently reduced the content of histamine and putrescine in huangjiu by 41.1% and 19.8%, respectively. The degradation rate for total biogenic amines in huangjiu was 20.5%. The results demonstrated the good performance of an ethanol tolerant multicopper oxidase in reduction of biogenic amines in alcohol beverages. This provides potential enzyme candidates for being used in food safety control.

Funding

National Natural Science Foundation of China,(32172182)