王 程 霍冀川 刘佳琪 袁艳红

摘要从啤酒废酵母泥中分离纯化出5株酿酒酵母,以其中单细胞蛋白(SCP)含量较高的SY-5为出发菌株,通过紫外诱变分生孢子,经过初筛和复筛,得到1株高产SCP的诱变菌株SY-5-7,比出发菌株高7.84%,达到48.67%。通过单因素试验对诱变菌株SY-5-7培养条件进行优化,结果表明,最适培养条件为培养基起始pH值5.0、培养温度26 ℃、接种量2%、发酵周期为70 h,碳源为50 g/L蔗糖、氮源为10 g/L酵母膏。在此基础上进行培养,SY-5-7的生物量比初始条件提高了约35%。

关键词酿酒酵母;单细胞蛋白;紫外诱变;培养条件

中图分类号 Q93 文献标识码A文章编号 1007-5739(2010)09-0016-03

ScreeningofYeastwithHigh-yieldSingle CellProteinbyUVMutationandOptimizationofitsCultureConditions

WANG ChengHUO Ji-chuan*LIU Jia-qiYUAN Yan-hong

(Institute of applied chemistry,Southwest University of Science and Technology,Mianyang 621010)

AbstractFive strains of Saccharomyces cerevisiae are isolated from waste brewer yeast,SY-5 which had a higher productivity of SCP was selected as the starting strain for stepwise mutation by UV irrigation. After primary and secondary screening,a high-yield SCP strain named SY-5-7 was obtained from its parent strain. The percentage of SCP yield of SY-5-7 was 48.67%,increased by 7.84% compared with the original strain. Then the cultivating condition of the mutant strain was optimized by single-factor test. It was found that the initial culturing pH value was 5.0,the culturing temperature was 26 ℃,culturing time was 70h,carbon source was 50 g/L of sucrose,nitrogen source was 10 g/L of yeast extract. Under this condition,the productivity of SY-5-7 was increased by 35% compared with the primary cultivating condition.

Key wordsSaccharomyces cerevisiae;single cell protein;UV irrigation;cultivating condition

单细胞蛋白(single cell protein,简称SCP),又称微生物蛋白,一般指酵母、非病源细菌、真菌等单细胞生物体内所含的蛋白质。酿酒酵母细胞中含有丰富的蛋白质,SCP含量占其细胞干物质的45%～55%,并且酿酒酵母被美国食品药物管理局(FDA)称为GRAS(generally recognized as safe)即安全无毒的[1]。由于酿酒酵母能在短时间内通过发酵大量培养,因此其可用于生产大量、合格的SCP产品。

从啤酒废酵母泥中分离所得到的原始酵母菌株用于生产SCP时,无论从产量还是质量上考虑均不乐观。如果单纯依靠自然选育,由于自然突变率低、突变幅度小,获得高产菌的几率非常小。利用紫外线诱发突变处理菌株是最为可靠的微生物菌种选育方法,具有便捷、经济且高效等特点[2]。

目前,利用酵母生产SCP的研究工作国内外报道较多,但主要集中在生产工艺上的研究,对于高产SCP酵母的诱变育种国内少有报道,因此本试验为提高SCP产量寻找一条新的有效的途径提供依据。……