以玉米芯为原料发酵生产富含虾青素的饲料酵母

Utilizing Maize Cobs as Fermentation Substrate to Produce Feed Yeast Rice in Astaxanthin by Phaffia rhodozyma

玉米芯是一种资源丰富的农副产品。采用氨水、稀酸、稀碱处理玉米芯 ,再用纤维素酶 -木聚糖酶复合酶系可将玉米芯水解生成可发酵性糖类 ,然后以法夫酵母作为菌种发酵来生产饲料酵母 ,从而获得了含有虾青素的饲料酵母 ,大大强化饲料酵母的营养 ,提高了酵母的价值。实验结果表明 ,8%的氨水和 4 %的氢氧化钠处理玉米芯 ,所得还原糖效率都较好 ;不同的初始糖浓度对酵母生长具有不同的影响 ,2 %的糖浓度有利于菌体的生长和虾青素的合成 ;酵母可能利用多种氮源进行生长 ,蛋白胨、鱼粉等有机氮有利于细胞的生长 ;[Goucose]/ [Ammoniumsulfate]=0 .7时细胞干重有较大值 ,而虾青素的浓度却在 [Goucose]/ [Ammoniumsulfate]=2时有较大值 ,为 2 .4 6mg/L。 5升罐上间歇培养中 ,最终细胞干重为 3.3g/L ,虾青素产率 2 .7mg/L。

Maize cob is a cheap and vast expanded by-product of agriculture.After pretreatment with ammonia(8%,w/v),sodium hydrate(4%,w/v)and dilute acid,the cobs were hydrolyzed by using cellulase and xylase preparations to liberate reduced sugars.The yeast Phaffia rodozyma can utilize these sugar as substrate for cell growth and astaxanthin synthesis.The experitments suggested that an initial sugar conentration of 2%(w/v),plus peptone or fish meal improved the yeast growth and astaxanthin accumulation.Different C/N ratio(Glucose Ammonium sulfate)influenced the yeast growth and astaxanthin yield at different level.In a 5-litre fermentor batch cultivation,biomass at 3.3g/L(dry cell weight) and astaxathin yield at 2.7mg/L were obtained.