镇江香醋核心酿造微生物醋酸杆菌和乳酸杆菌共培养对生长代谢的影响

Effect of co-culture of Acetobacter and Lactobacillus strains on growth and metabolism of the key functional microbes during Zhenjiang aromatic vinegar fermentation

【目的】研究镇江香醋酿造过程核心功能微生物醋酸杆菌属与乳酸杆菌属菌株之间的相互作用关系。【方法】本文以分离到的镇江香醋酿造中的核心微生物2株醋酸杆菌和8株孔酸杆菌为研究对象,构建醋酸杆菌和乳酸杆菌共培养发酵体系,比较异位与原位条件下,纯培养及共培养中菌株的生长和代谢(包括还原糖、乙醇和总酸等含量)差异;采用GC-MS检测原位共培养中挥发性物质的变化,分析微生物间的交互作用对镇江香醋主要风味物质形成的潜在影响。【结果】醋酸杆菌和乳酸杆菌之间的交互作用具有种间特异性和环境特异性,A.pasteurianus G3-2和L.helveticus M3-1、L.plantarum M10-1、L.pontis M17-5及L.reuteri GE7-1在异位及原位模拟共培养中整体的生长和代谢优于纯培养;A.pomorum G15-6和L.paracasei E1-1在异位和原位共培养下还原糖利用率和总酸的产生率都低于纯培养,和L.helveticus M3-1、L.reuteri GE7-1、L.plantarum M10-1、L.fermentum M10-3、L.casei E10-1、L.pontis M17-5、L.hilgardii M3-4共培养在异位和原位模拟中代谢不一致。根据GC-MS分析显示,A.pasteurianus G3-2和L.helveticus M3-1及L.reuteri GE7-1原位模拟共培养时异戊酸、乙酸乙酯、甲酸辛酯等风味物质的含量明显优于纯培养,其中一种重要风味物质2,3-丁二酮只在共培养时被检出,其含量分别达到了9.87 mg/L及14.28 mg/L。【结论】镇江香醋醋醅中的醋酸杆菌和乳酸杆菌之间的交互作用能够影响菌株生长和主要代谢产物生成,这一研究有助于深入剖析镇江香醋风味形成的酿造机理,为理性调控酿造菌群以改善镇江香醋风味品质奠定了理论基础。

[Objective]To better explain the metabolic mechanism of microbial community during Zhenjiang vinegar fermentation,we studied the interaction between Acetobacter and Lactobacillus,the key functional microorganisms during multispecies solid-state acetic acid fermentation.[Methods]Here,two strains of Acetobacter and eight strains of Lactobacillus isolated from vinegar fermentation culture,namely,Acetobacter pasteurianus G3-2,A.pomorum G15-6,Lactobacillus paracasei E1-1,L.helveticus M3-1,L.reuteri GE7-1,L.plantarum M10-1,L.fermentum M10-3,L.casei E10-1,L.pontis M17-5,L.hilgardii M3-4,were selected for microbial growth and metabolism analysis in monoculture and coculture fermentation.We compared the differences of interaction types between in vitro fermentation and in situ fermentation,then GC-MS was used to analyze the effects of interaction on the flavor of Zhenjiang vinegar.[Results]Synergistic effect between A.pasteurianus G3-2 and L.helveticus M3-1,L.plantarum M10-1,L.pontis M17-5 and L.reuteri GE7-1 in vitro fermentation and in situ fermentation was identified.Negative effect between A.pomorum G15-6 and L.paracasei E1-1,however,A.pomorum G15-6 showed different effects on L.plantarum M10-1,L.pontis M17-5 and L.reuteri GE7-1 in vitro fermentation and in situ fermentation.Coculture of A.pasteurianus G3-2 and L.helveticus M3-1,L.reuteri GE7-1 showed better performance in 2,3-butanedione,valeric acid,ethyl acetate and octyl formate production than monoculture,and the yield of 2,3-butanedione increased from none detected to 9.87 mg/L and 14.28 mg/L.[Conclusion]The interaction between Lactobacillus and Acetobacter in Cupei can affect the changes of main metabolites and volatile substances.This work provides a theoretical basis for in-depth analysis of the brewing mechanism of Zhenjiang vinegar,lays the foundation for rational regulation of the microbial community and improving the flavor and quality of Zhenjiang vinegar.