丹参内生镰刀菌HBG16胞外多糖发酵条件优化及其抗氧化能力

Optimization of the Fermentation Conditions for Production of Extracellular Polysaccharides of Endophytic Fungus HBG16from Salvia Miltiorrhiza Bunge and Its Antioxidant Capacity

目的:优化丹参内生镰刀菌HBG16发酵工艺条件来提高胞外多糖产量,并分析其抗氧化能力。方法:通过单因素实验和响应面试验对产胞外多糖丹参内生镰刀菌HBG16的碳源、氮源、接种量、p H四个因素进行优化;通过凝胶渗透色谱法(GPC)进行样品单糖组成分析;通过DPPH法测定胞外多糖抗氧化能力。结果:通过单因素实验确定内生镰刀菌HBG16的碳源为麦芽糖,氮源为酵母粉,p H为6.0,接种量为6%;经响应面试验确定最佳发酵条件为麦芽糖32 mg/m L,酵母粉2.6 mg/m L,p H为6.0,接种量6%,在此优化条件下,发酵液胞外多糖的含量达到0.95 mg/m L,与预测值的偏差为2.06%。多糖主要由半乳糖组成,含量为52.09 mg/kg。随着胞外多糖浓度的增加,对DPPH自由基清除率增加。多糖清除DPPH自由基的IC50为0.38 mg/m L。结论:在优化的培养条件下,丹参内生镰刀菌HBZ16胞外多糖产量由0.11 mg/m L提高到0.95 mg/m L,为真菌多糖的工业化利用奠定了基础。

Objective： The fermentation conditions for extracellular polysaccharide production in endophytic fungus HBG16 isolated from Salvia miltiorrhiza Bunge were optimized and its antioxidant capacity was analyzed. Method： Single factor experiment and response surface methodology were applied to optimize carbon source,nitrogen source,inoculation amout and pH of endophytic fungus HBG16.The monosaccharide composition of the sample was analyzed by gel permeation chromatography（ GPC）. The free radical scavenging ability of extracellular polysaccharide was measured by DPPH method.Results： The results of single factor showed that the carbon source,nitrogen source,pH,and inoculation of fermentation were maltose,yeast powder,pH6.0,and inoculation amout 6%,respectively. The optimum fermentation conditions were maltose32 mg/mL,yeast powder 2.6 mg/mL,pH6.0,inoculation 6%. And the yield of extracellular polysaccharide reached 0.95 mg/mL under this optimized condition.The polysaccharides were mainly composed of galactose,with a content of 52.09 mg/kg.With the increase of extracellular polysaccharide concentration,the free radical scavenging rate of DPPH was increased. The semi inhibitory amount（ IC50） of DPPH free radical scavenging was 0.38 mg/mL.Conclusion： Under the optimized culture conditions,the production of extracellular polysaccharide of endophytic fungus HBG16 was increased from 0.11 mg/mL to 0.95 mg/mL,which laid a foundation for the industrial utilization of fungal polysaccharides.