培养基优化实验表明,马铃薯葡萄糖培养基是干巴菌的最适产糖培养基,菌丝体产量和菌丝体多糖产量分别可达7.56 g/L和0.42 g/L。采用Plackett-Burman试验及响应面试验优化干巴菌多糖的提取工艺,结果表明,极显著影响因素及其最优条件为超声功率400 W、超声时间10 min、醇沉倍数3倍,优化后多糖得率可达6.98%。体外抗氧化实验证明,干巴菌多糖具有良好的抗氧化活性,并且酶水解(纤维素酶、蜗牛酶)和酸水解(硫酸)均可使多糖的抗氧化能力显著增强。采用逐级酸水解结合柱前衍生高效液相色谱法分析多糖结构,其单糖残基分布规律为:支链末端残基由半乳糖和少量甘露糖构成;半乳糖大多分布于支链外侧及支链末端;葡萄糖是主要单糖组分,主要分布于主链及支链内侧;甘露糖主要分布于支链内侧。本研究为酶水解及酸水解方法在多糖领域中的应用及干巴菌多糖的资源开发提供理论基础。
Optimization experiments showed that potato glucose medium was the optimal medium for sugar production by Thelephora ganbajun Zang, and using this medium, the mycelial yield and mycelial polysaccharide yield were 7.56 and 0.42 g/L, respectively. Plackett-Burman design and response surface methodology were used to optimize the ultrasonicassisted extraction of T. ganbajun Zang polysaccharides. Ultrasonic power, irradiation time and alcohol precipitation fold were found to be significant factors affecting the polysaccharide yield and their optimal levels were 400 W, 10 min and 3,respectively, which resulted in maximum polysaccharide yield of 6.98%. The results of in vitro antioxidant tests showed that the polysaccharides had a strong antioxidant capacity, and hydrolysis with enzymes(cellulase and snailase) or acid(sulfuric acid) could significantly enhance the antioxidant capacity of the polysaccharides. Monosaccharide composition analysis by stepwise acid hydrolysis combined with pre-column derivatization high performance liquid chromatography showed that the terminal residues of branches of the polysaccharides were composed of galactose as well as a small amount of mannose;galactose was mostly distributed on the outer side and at the end of the branches;glucose was the main monosaccharide component, and it was mainly distributed in the main chain and the inside of the branches;mannose was mainly distributed inside the branches. This study lays a theoretical foundation for the application of enzymatic hydrolysis and acid hydrolysis on polysaccharides and the exploitation and utilization of T. ganbajun Zang polysaccharides.
Thelephora ganbajun Zang