自然发酵酱油酱醅中产香芽孢杆菌的筛选及其产酶性能研究

Screening of flavor-producing Bacillus from naturally fermented soy sauce moromi and its enzyme production capacity

运用培养法及16S rDNA序列分析鉴定从传统技艺酿制的高盐固态发酵型酱油——先市酱油酱醅中分离到9株细菌,均为芽孢杆菌属。牛津杯水解圈法分析此9株芽孢杆菌在高盐环境中产蛋白酶、淀粉酶和纤维素酶能力,以及罗丹明B平板法分析其产脂肪酶能力显示,所分离菌株均能分泌蛋白酶、淀粉酶和纤维素酶,其中6株能够分泌脂肪酶。HS-SPME-GC/MS检测分离菌株发酵液发现含有挥发性代谢产物15种,全部分离菌株均能生成苯乙醇、愈创木酚和2,4-二叔丁基苯酚,因此所筛芽孢杆菌均具有一定产香能力。优选出2株能够产生1-辛烯-3-醇、苯乙醛、苯乙醇、愈创木酚和2-戊基呋喃等酱油重要香气物质的芽孢杆菌XS-4和XS-6,经感官评价分析发现二者发酵液具有酱香特征。该研究揭示了先市酱油酱醅中的芽孢杆菌具有促进酱醅原料分解和产生香气的能力,筛选出的XS-4和XS-6两株芽孢杆菌显示出较强产酱香能力,具有良好应用前景。

A total of nine Bacillus strains were screened by classical culturing and 16S rDNA sequence analysis from the moromi of Xianshi soy sauce via natural high-salt solid-state fermentation.The Oxford cup hydrolysis circle method was used to analyze the protease,amylase,and cellulase production capacity of these strains under high salty environment,and the rhodamine B plate for the lipase.All the Bacillus strains screened could secrete protease,amylase and cellulase,among which six could secrete lipase.About 15 volatile compounds were detected from their fermentation broth by HS-SPME-GC/MS,and phenylethyl alcohol,guaiacol and 2,4-di-tert-butylphenol existed,therefore,all strains screened were able to produce typical aroma compounds for soy sauce.Two Bacillus strains that produced key aroma compounds of 1-octene-3-ol,phenylacetaldehyde,phenethyl alcohol,guaiacol and 2-pentylfuran were selected,namely XS-4 and XS-6.Sensory analysis showed that their fermentation broth had the characteristics Jiang-flavor.Our study revealed that the Bacillus has the ability to promote fermentation process and enhance the characteristic aroma of soy sauce in Xianshi soy sauce,with XS-4 and XS-6 of high application potential to produce soy sauce Jiang aroma.