高效降解游离棉酚并改善棉籽粕营养品质的菌株筛选

摘要

本试验旨在利用枯草芽孢杆菌和植物乳酸菌发酵棉籽粕,研究其对棉籽粕中游离棉酚降解率的影响,并对发酵前后棉籽粕的营养品质指标如活菌数、中性蛋白酶活性、酸溶蛋白质含量、pH、游离棉酚含量等进行比较.结果发现:可高效降解棉籽粕中游离棉酚的枯草芽孢杆菌菌株为BLCC1-0039,可有效改善发酵风味的植物乳酸菌菌株为BLCC2-0092.综合上述2株益生菌的优点,筛选出最优复配发酵方式为植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039按照1∶1比例接种,37 ℃需氧发酵24 h再厌氧发酵.与空白对照组相比,最优复配发酵组各发酵阶段发酵棉籽粕的pH显著降低(P<0.05),厌氧发酵72 h时pH降至5.27;酸溶蛋白质含量显著提高(P<0.05),厌氧发酵72 h时酸溶蛋白质含量达到23.54%;游离棉酚含量显著降低(P<0.05),需氧发酵24 h时游离棉酚降解率达到52.12%,厌氧发酵72 h时游离棉酚降解率达到61.58%.由此可知,植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039复配发酵可有效降低发酵棉籽粕中的游离棉酚含量并改善其营养品质.%This experiment was conducted to study the effects of cottonseed meal fermented by Bacillus subtilis and Lactobacillus plantarum on free gossypol degrading rate of cottonseed meal,and to compare the nutritive quality indices of cottonseed meal before and after fermentation,such as viable count of bacteria,neutral proteases activity,pH,acid-soluble protein content and gossypol content,etc.The results showed that the Bacillus subtilis BLCC1-0039 had high efficient free gossypol-degrading capacity and the Lactobacillus plantarum BLCC2-0092 had improving fermentation flavor capacity.Comprehensive the advantages of Bacillus subtilis BLCC1-0039 and Lactobacillus plantarum BLCC2-0092,the optimal compound fermentation conditions were showed as follows: the inoculative proportion of Bacillus subtilis BLCC1-0039 and Lactobacillus plantarum BLCC2-0092 was 1∶1,24 h for aerobic fermentation and then anaerobic fermentation.Compared with control check group,the pH of fermented cottonseed meal in each fermentation stage of optimal compound fermentation group was significantly decreased (P<0.05),and the pH after anaerobic fermentation 72 h reduced to 5.27;the acid-soluble protein content was significantly (P<0.05),and the acid-soluble protein content after anaerobic fermentation 72 h increased to 23.54%;the feed gossypol content was significantly decreased (P<0.05),and the free gossypol degrading rate after aerobic fermentation 24 h and anaerobic fermentation 72 h reached to 52.12% and 61.58%,respectively.It is concluded that compound fermentation of Bacillus subtilis BLCC1-0039 and Lactobacillus plantarum BLCC2-0092 can effectively degrade the content of free gossypol in cottonseed meal and improve the nutritive quality of cottonseed meal.