微杆菌XL1胞外多糖发酵条件优化及其活性研究

Study on the Optimization of Fermentation Conditions and Activity of Extracellular Polysaccharide from Microbacterium XL1

关键词:  微杆菌  单因素法  吸湿保湿  抗氧化  酪氨酸酶

Key words:  Microbacterium  single factor method  moisture absorption and moisturizing  antioxidation  tyrosinase

摘要:

为提高微杆菌Microbacterium XL1胞外多糖的产量，探究其生理活性功能，本研究采用单因素法优化微杆菌XL1发酵产胞外多糖的碳、氮源种类及添加量、温度、初始pH和发酵时间，并对微杆菌XL1胞外多糖的吸湿保湿性能、抗氧化活性以及酪氨酸酶抑制活性进行测试。结果表明，微杆菌XL1产胞外多糖的最佳条件如下：蔗糖为碳源、酵母提取物为氮源，蔗糖添加量为20%、酵母提取物添加量为0.3%，温度20℃，pH值为8.0，发酵时间24 h。在最佳条件下，胞外多糖产量最高达92 g/L，是优化前的3.2倍。同时，微杆菌XL1胞外多糖的吸湿、保湿性能与透明质酸相似，其对DPPH自由基、羟基自由基和铁离子的半数抑制浓度（IC₅₀）分别为1.2，0.8和0.3 mg/mL，对酪氨酸酶的抑制率可达55%。本研究提高了微杆菌XL1胞外多糖的产量，并证实微杆菌XL1胞外多糖具有优良的生理活性，对丰富微杆菌胞外多糖活性的研究有重要意义，可为其在化妆品和食品行业中的开发应用提供理论依据。

Abstract:

In order to improve the yield of extracellular polysaccharide from Microbacterium XL1 and explore its physiological activity function,a single factor method was used to optimize the types of carbon and nitrogen sources and the amount of addition,temperature,initial pH,and fermentation time for the production of extracellular polysaccharides by Microbacterium XL1 in this study.The moisture absorption and moisturizing performance,antioxidant activity and tyrosinase inhibitory activity of Microbacterium XL1 extracellular polysaccharide were tested.The results showed that the optimal conditions for the production of extracellular polysaccharides by Microbacterium XL1 were that sucrose was the carbon source,yeast extract was the nitrogen source,the sucrose addition was 20%,the yeast extract was 0.3%,the temperature was 20℃,and the pH value was 8.0,and the fermentation time was 24 h.Under the optimal conditions,the yield of extracellular polysaccharide reached 92 g/L,which was 3.2 times higher than that before optimization.At the same time,the moisture absorption and moisturizing properties of Microbacterium XL1 extracellular polysaccharide were similar to that of hyaluronic acid.The half inhibitory concentration (IC₅₀) of DPPH free radicals,hydroxyl free radicals and iron ions were 1.2,0.8 and 0.3 mg/mL,respectively.The inhibition rate on tyrosinase could reach 55%.This research have improved the yield of Microbacterium XL1 extracellular polysaccharides and confirmed that Microbacterial XL1 extracellular polysaccharides have excellent physiological activity,which is of great significance to enrich the study of the activity of extracellular polysaccharide of Microbacterium,and provide a theoretical basis for its development and application in cosmetics and food industries.