单 位：
广东省林业科学研究院广东省森林培育与保护利用重点实验室;南京林业大学江苏省林业资源高效加工利用协同创新中心
关键词：
葡甘露聚糖;葡甘露低聚糖;甘露聚糖酶;肠道微生物;增殖
摘 要：
为提高酶法制备葡甘露低聚糖得率,并阐明其对肠道微生物增殖的作用,研究了不同碳源诱导物对甘露聚糖酶酶系组成以及葡甘露聚糖酶解过程中工艺参数对葡甘露低聚糖得率的影响,研究了葡甘露低聚糖对典型肠道微生物的增殖作用及其代谢产物。结果表明,微晶纤维素是里氏木霉合成甘露聚糖酶的最佳碳源诱导物,里氏木霉以10 g/L微晶纤维素为诱导物产酶,β-甘露聚糖酶活力为3.902 U/mL,β-甘露糖苷酶活力为0.019 U/mL,两者酶活比为205.4∶1.0。15 g/L葡甘露聚糖在甘露聚糖酶用量10 U/g、50℃、pH 4.8条件下水解8 h,葡甘露低聚糖得率可达73.70%,酶对葡甘露低聚糖的选择性为85.60%。以3 g/L葡甘露低聚糖为碳源的肠道微生物进行体外培养,结果显示长双歧杆菌等14种有益菌能有效利用葡甘露低聚糖进行增殖和代谢,产生短链脂肪酸,而平肠球菌等3种潜在致病菌几乎不能利用葡甘露低聚糖;长双歧杆菌(Bifidobaterium longum ATCC15697)和嗜酸乳杆菌(Lactobacillus acidophilus B-4495)的增殖效果最好,分别增殖了27.0和19.5倍,生成的短链脂肪酸(乙酸、丙酸、丁酸和乳酸)浓度分别为(78.5±3.5)和(42.6±2.6) mmol/L。
译 名：
Enzymatic preparation of glucomannan oligosaccharides and their effects on intestinal microbial proliferation
作 者：
WANG Rong;WANG Jing;LAI Chenhuan;HUANG Caoxing;LIN Zhe;YONG Qiang;Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University;Guangdong Provincial Key Laboratory of Silviculture Protection and Utilization,Guangdong Academy of Forestry;
关键词：
glucomannan;;glucomannan oligosaccharides;;mannanase;;intestinal microbes;;proliferation
摘 要：
In order to improve the yield of glucomannan oligosaccharides(GMOS) prepared by enzymatic hydrolysis, understanding their effects of GMOS on intestinal microbial proliferation, the influence of different inducers on the compositions of mannanase enzyme system was investigated. Additionally, the effects of the process parameters on the glucomannan oligosaccharides yield during the enzymatic hydrolysis of glucomannan, and glucomannan oligosaccharides on the proliferation and metabolites of intestinal microbes were studied. The results showed that the microcrystalline cellulose was the best inducer for the synthesis of mannanase by Trichoderma reesei when the T. reesei employed 10 g/L microcrystalline cellulose for the mannanase preparation, the β-mannanase and β-mannosidase activity were 3.902 U/mL and 0.019 U/mL, respectively, and the ratio of β-mannanase activity to β-mannosidase activity was 205.4∶1.0. Besides, microcrystalline cellulose can induce T. reesei to synthesize cellulose, mannanase and xylanase at the same time. 15 g/L glucomannan was hydrolyzed by mannanase at the dosage of 10 U/g glucomannan, 50 ℃, pH 4.8 for 8 h, the glucomannan oligosaccharides yield of 73.70% and the enzyme selectivity to glucomannan oligosaccharides of 85.60% were obtained, respectively. 17 kinds of intestinal microorganisms were cultured in vitro with 3 g/L glucomannan oligosaccharides as carbon source for 48 h, and 14 kinds of beneficial bacteria could effectively utilize oligosaccharides for proliferation and producing short-chain fatty acids. While three kinds of potential pathogenic bacteria such as Enterococcus hirae B-1295 cannot consume glucomannan oligosaccharides, the concentrations of E. hirae B-1295, Campylobacter jejuni S107 and Escherichia coli K12 cultured by 3 g/L glucomannan oligosaccharide were 0.07 g/L, 0.03 g/L and 0.02 g/L with the initial mass concentration of 0.02 g/L, respectively. The best proliferation effects of Bifidobaterium longum ATCC15697 and Lactobacillus acidophilus B-4495 were obtained, in which, the proliferation rates were 27.0 and 19.5, respectively, and the concentration of total short-chain fatty acids(acetic acid, propionic acid, butyric acid and lactic acid) produced were(78.5±3.5) and(42.6±2.6) mmol/L, respectively. Lactic acid and butyric acid were the main short chain fatty acids produced by B. longum ATCC15697 and L. acidophilus B-4495, which were(38.9±1.2),(32.1±7.1),(25.0±3.0) and(14.0±4.0) mmol/L, respectively. The acetic acid and propionic acid were low, which were only(4.5±0.4),(1.6±0.3),(0.3±0.1) and(0.8±0.2) mmol/L, respectively. The concentrations of short chain fatty acids produced by other beneficial bacteria were relatively low, ranging from 3.0 to 32.0 mmol/L. In addition to 9.9 mmol/L short chain fatty acids produced by C. jejuni S107, E. hirae B-1295 and E. coli K12 produced very few short chain fatty acids(0.6 and 0.9 mmol/L).
