作　　者： (董晨）; (张锦华）; (白宝清）; (徐蔓）;

机构地区： 山西大学生命科学学院,山西太原030006

出　　处： 《食品与发酵工业》 2017年第8期67-72,共6页

摘　　要： 筛选出在酸性环境下高效降解柠檬苦素的菌株,扩展了生物法消除柑橘果汁中的苦味物质的应用领域。从新鲜醋醅中粗筛并分离出以柠檬苦素为唯一碳源的8株菌,其相应的柠檬苦素降解率均达70%以上,其中6、7、8号菌的柠檬苦素降解率较高,分别为95.14%、98.21%和94.31%。比较3株高效降解菌的胞外蛋白、胞内蛋白和菌液的柠檬苦素降解能力,3株菌中具有降解柠檬苦素的活性蛋白酶主要分布在细胞外,属于胞外蛋白酶,胞内蛋白对柠檬苦素几乎无降解作用,其中6号菌株胞外酶的柠檬苦素降解活性最强,柠檬苦素降解率为45.57%。形态学观察及分子生物学鉴定6、7、8号菌均属于拉乌尔菌属(Raoultella sp.)。菌株6具有高效降解柠檬苦素能力,能够成为今后降解柠檬苦素微生物源的优势菌种。 To screen the limonin-degrading strains with the high efficiency in the acidic environment, the study extended the application area of the bioanalysis to eliminate bitter substances in citrus juice. Eight limonin-degrading strains using limonin as the sole carbon source were isolated from fresh fermented grains of vinegar, and their corre-sponding limonin degradation rates were all above 70% in the cultured system. Among them, strains 6, 7, 8 exhibited higher degradation rates than others of 95.14% , 98.21% , 94.31% respectively. Comparing the limonin degradation ability of extracellular protein, intracellular protein, and bacterial fluid in three strains 6, 7, 8, the results indicated that enzymes having limonin degradation ability were located at extracellular position of these three strains. There was almost no limonin degradation for intracellular protein of three strains, and extracellular enzymes of strain 6 had the strongest limonin degradation ability with the limonin degradation rate of 45.57%. Based on morphological observations and molecular biology identifications, strains 6, 7, 8 were identified as Raoultella sp.. The strain 6 ex- hibiting the highest limonin-degrading capacity could be used as an excellent species for the degradation of limonin in the future.

关 键 词： 柠檬苦素 降解 筛选 鉴定 酶系定位