重组4-甲基苯酚消减乳酸菌的构建及其在白酒酿造体系中的功能

Construction of p-cresol reduction recombinant lactic acid bacterium to decrease p-cresol in Chinese liquor fermentation

摘要:

【背景】4-甲基苯酚是众多发酵食品中的异嗅味物质，阈值较低，如白酒中百万分之一的4-甲基苯酚即可对白酒风味造成不利影响。【目的】构建能消减4-甲基苯酚的乳酸菌菌株，探索其在白酒酿造中的应用潜力。【方法】将来源于谷氨酸棒杆菌的4-甲基苯基磷酸酯合成酶编码基因creI与creH在短乳杆菌中表达，探究过表达菌株对白酒酿造体系中4-甲基苯酚的消减能力。【结果】creIH过表达菌株在液体培养基中可有效消减4-甲基苯酚，消减能力达2 130 μg/L；在模拟白酒固态酿造体系中，creIH过表达菌株消减4-甲基苯酚的能力达530 μg/kg，消减率为37.9%。【结论】首次构建了4-甲基苯酚的消减乳酸菌菌株，为白酒酿造体系中4-甲基苯酚的消减提供了新的策略。

Abstract:

[Background] p-cresol is an off-odor in a variety of fermented foods. With low threshold, ppm’s p-cresol can adversely affect the flavor of Chinese liquor. [Objective] Recombinant lactic acid bacterium with p-cresol reduction capability was constructed and tested in Chinese liquor fermentation. [Methods] The genes (creI and creH) coding 4-methylbenzyl phosphate synthase were cloned from Corynebacterium glutamicum and ectopically expressed in Lactobacillus brevis. The reduction capability of creIH overexpression strain was determined in Chinese liquor fermentation. [Results] The creIH overexpression strain eliminated p-cresol up to 2 130 μg/L in liquid medium and 530 μg/kg in simulated solid-state fermented grains. The reduction rate in simulated solid-state fermentation reached 37.9%. [Conclusion] This is the first report that lactic acid bacterium with p-cresol reducing capability was constructed. It provides a novel strategy to eliminate p-cresol in Chinese liquor fermentation.