硫苷降解菌筛选及改良菜籽粕营养特性的研究Screening of glucosinolates-degrading bacteria and their role in improving the nutrition characteristics of rapeseed meal

为改善菜籽粕的营养价值，以腐烂菜籽粕为原料，硫苷为唯一碳源，筛选可高效降解菜籽粕中主要抗营养因子硫苷的菌株，并经16S rRNA基因序列分析对其进行种属鉴定。以筛选得到的菌株和枯草芽孢杆菌、植物乳杆菌单菌或组合菌对菜籽粕进行固态发酵，并以硫苷降解率和粗蛋白质增加率为指标，采用综合评分法对混菌发酵菌株接种量进行优化。结果表明：获得2株硫苷降解率大于25%的菌株B3、B16，经鉴定分别为欧文氏杆菌（Erwinia tasmaniensis）、鸡肠球菌（Enterococcus gallinarum）；相较于单菌发酵和两菌、三菌组合发酵，四菌组合发酵的硫苷降解效果最好；四菌组合发酵中B3、B16、枯草芽孢杆菌与植物乳杆菌接种量分别为15%、5%、15%、10%时，固态发酵菜籽粕中硫苷含量为(18.97±0.29)μmol/g，降解率为(39.31±0.91)%，粗蛋白质含量为(33.54±012)%，增加率为(33.62±0.47)%。综上，通过混菌固态发酵菜籽粕可有效降解硫苷，提高粗蛋白质含量，改善菜籽粕营养价值。In order to improve the nutrition value of rapeseed meal, using rotten rapeseed meal as the raw material and glucosinolates as the only carbon source, strains of efficiently degrading the main anti-nutrient factor glucosinolates in rapeseed meal were screened, and their species were identified by 16S rRNA gene sequence analysis. Solid state fermentation of rapeseed meal was carried out by single bacteria or mixed bacteria using the screened strains and Bacillus subtilis and Lactobacillus plantarum. The inoculation amount of the strains in mixed bacterial fermentation was optimized using a comprehensive scoring method based on the degradation rate of glucosinolates and the increase rate of crude protein. The results showed that two strains B3 and B16 with glucosinolates degradation rate greater than 25% were obtained, and they were identified as Erwinia tasmaniensis and Enterococcus gallinarum, respectively. Compared with single bacteria, two bacteria and three bacteria combined fermentation, four bacteria combined fermentation had the best effect on glucosinolates degradation of rapeseed meal. When the inoculation amount of B3, B16, Bacillus subtilis and Lactobacillus plantarum was 15%, 5%, 15% and 10% respectively, the glucosinolates content was (18.97±0.29) μmol/g with the degradation rate of (39.31±0.91)%, and the crude protein content was (33.54±0.12)%, with the increase rate of (33.62±0.47)% in rapeseed meal after solid state fermentation. In conclusion, solid state fermentation of rapeseed meal with mixed bacteria can effectively degrade glucosinolates, increase crude protein content and improve the nutritional value of rapeseed meal.