废蜜原料液体发酵蛹虫草菌丝体和多糖的条件

废蜜（糖蜜）是制糖工业的主要副产物之一,含有很多微生物可利用的成分,是一种廉价的生产原料.以甜菜糖蜜为原料,通过液体发酵方法生产蛹虫草菌丝体.以蛹虫草菌丝体生物量为主要指标,发酵液中胞外多糖做为次要指标,运用单因素对比试验和正交实验,对蛹虫草液体培养基中的氮源以及培养条件进行优化.结果表明：有机氮源比无机氮源更有利于蛹虫草液体发酵;大豆分离蛋白与蛋白胨以4：1的比例混合,不仅能降低生产成本,还能促进菌丝生物量及胞外多糖的积累;发酵的最适培养条件为：摇床转速180r/min、装液量50/250ml、培养温度23℃、接种量8％ （v/v）,优化条件下蛹虫草液体培养生物量达到42.71 mg/ml,培养液中多糖含量达到5.97mg/ml.

Production of cordyceps militaris biomass and extracellular polysaccharides by submerged culture using molasses as major material

Molasses is one of the main by - products of beet sugar production. It is an inexpensive raw materials in fermentation industry because it contains a lot of ingredients which is available for microorganism. In this arti- cle, molasses as raw material, liquid fermentation method was used for producing Cordyceps militaris mycelia. Nitrogen sources,including type of nitrogen and mixing ratio, fermentation conditions, including shaking speed, liquid volume in flask, temperature, inoculation size, were optimized using the mycelia biomass as major criteri- on and extracellular polysaccharide as a secondary criterion. The resuhs showed that organic nitrogen was more suitable for the liquid fermentation of Cordyceps than inorganic nitrogen, and the mixture of soy protein isolate and peptone in the ratio of 4 ： 1, which is benefit for reducing the production cost, was suitable for producing of the mycelium biomass and accumulating of extracellular polysaccharides. The optimized fermentation conditions was shaking speed of 180r/min, liquid volume of 50/250ml, culture temperature of 23 ℃ and inoculation size of 8% （v / v）. Under optimized condition the mycelium biomass and extracellular polysaccharides reached 42. 71 mg/ml and 5.97mg/ml respectively.