多糖类益生元的筛选及凝结芽孢杆菌体外发酵特性

Screening of polysaccharide-based prebiotics and in vitro fermentation characteristics of Bacillus coagulans

摘要:

【目的】探究9种多糖对凝结芽孢杆菌(Bacillus coagulans)的增殖、产酶特性的影响。【方法】将凝结芽孢杆菌分别添加至菊粉多糖(inulin polysaccharide)、刺五加多糖(Eleutherococcus senticosus polysaccharide)、壳寡糖(chitosan oligosaccharide)、防风多糖(Saposhnikovia divaricata polysaccharide)、低聚木糖(xylo-oligosaccharide)、黄芪多糖(Astragalus polysaccharide)、甘露糖(d-mannose)、白术多糖(Atractylodes macrocephala Koidz polysaccharide)和玉屏风多糖(Yu Ping Feng polysaccharide)为唯一碳源的培养基中，通过菌株生长、酶活性及其体外厌氧发酵等作为指标，筛选出最优益生元。【结果】凝结芽孢杆菌能很好地利用防风多糖、黄芪多糖、白术多糖和玉屏风多糖；添加量为4%的防风多糖和白术多糖，pH差值差异最大，蛋白酶活性差异显著(P<0.05)。体外发酵乳酸活性和总蛋白酶活性均提高，4%白术多糖的乳酸和总蛋白酶活性差异显著(P<0.05)；肠道内容物发酵液16S rRNA基因高通量测序结果表明，与对照组比较，添加黄芪多糖、防风多糖、甘露糖3种益生元发酵凝结芽孢杆菌显著降低了气单胞菌(Aeromonas)、α-变形菌(α-Proteobacteria)、链球菌(Streptococcus)、志贺氏杆菌属(Shigella)等致病菌的相对丰度，提高了乳杆菌(Lactobacillus)、厚壁菌门(Firmicutes)、乳酸乳球菌(Lactococcus lactis)、产酸杆菌(Acidobacteria)的相对丰度。【结论】凝结芽孢杆菌发酵4%白术多糖具有较好的产酶性能与益生特性，二者协同发酵添加至饲料中具有较好的发展潜力。

Abstract:

[Objective] To investigate the effects of nine polysaccharides on the proliferation and enzyme production characteristics of Bacillus coagulans. [Methods] B. coagulans was co-fermented with inulin polysaccharide, Eleutherococcus senticosus polysaccharide, chitosan oligosaccharide, Saposhnikovia divaricata polysaccharide, xylo-oligosaccharide, Astragalus polysaccharide, d-mannose, Atractylodes macrocephala Koidz polysaccharide, and Yu Ping Feng polysaccharide as the only carbon source in the medium, respectively. The optimal polysaccharides were screened based on the strain growth, enzyme activities, and in vitro anaerobic fermentation performance. [Results] B. coagulans could well utilize the polysaccharides of Astragalus, S. divaricata, A. macrocephala, and Yu Ping Feng. The significant differences in pH and protease activity (P<0.05) after fermentation were found between 4% A. macrocephala polysaccharide and 4% S. divaricata polysaccharide. After in vitro fermentation, the lactic acid content and total protease activity increased, which were the highest in the 4% A. macrocephala polysaccharide group (P<0.05). The results of 16S rRNA gene sequencing of intestinal contents fermentation liquid showed that B. coagulans fermented with Astragalus polysaccharide, S. divaricata polysaccharide, and d-mannose significantly reduced the relative abundance of pathogenic bacteria such as Aeromonas, α-Proteobacteria, Streptococcus, and Shigella and improved that of Lactobacillus, Firmicutes, Lactococcus lactis, and Acidobacteria compared with the control group. [Conclusion] B. coagulans fermented with 4% A. macrocephala polysaccharide has good enzyme production and probiotic properties, which has a good potential for application in aquatic feed.