Effect of pesticide residues on simulated beer brewing and its inhibition elimination by pesticide-degrading enzyme

Abstract

Four different pesticide residues used in barley planting were selected to investigate their effects on simulated beer brewing. The influences were found to be different by varied agricultural chemicals. Among the four types of pesticides, at 25μg/mL, triadimefon or carbendazim barely affected the brewing progress. However, ethametsulfuron-methyl and carbaryl (15μg/mL and 2.5μg/mL, respectively) exhibited slightly inhibition on saccharification and significantly negative impacts on yeast growth and alcohol fermentation. After pretreated by 50μL carbaryl-degrading enzyme with the Kcat value of 2.12s-1 at 30°C for 90min, the negative influence on simulated beer brewing brought by carbaryl can be eliminated in the fermentation system containing 2.5μg/mL carbaryl. The efficiency of ethanol fermentation was improved, and the removal rate of carbaryl in the brewing system was greatly accelerated. Taken together, this study suggested a potential method for solving the fermentation inhibition by pesticide residues.