摘要
核糖核酸(RNA)是一类重要的生物大分子,在基因表达和蛋白质生物合成中起关键作用,其降解产物核苷酸可用于食品和医药中间体。目前,通常以解脂假丝酵母作为RNA的高产菌株,缺点是其属于致病菌。大量应用于食品工业的酿酒酵母虽然无致病性,但其RNA含量仅为细胞干重的3.0%左右。该研究采用硫酸二乙酯(DES)化学诱变,利用氯化钾敏感性筛选,以期提高酿酒酵母CGMCC NO.2448产RNA的含量。实验从100株突变株中筛选出一株高RNA含量、生长良好的酿酒酵母Y78,细胞质量浓度和RNA质量分数分别为4.5 g/L和5.02%。分批发酵时,在对数生长期,突变株Y78的RNA质量分数高于原始菌株,8 h达到最大为5.18%,是原始菌株RNA质量分数4.16%的1.25倍。相比原始菌株,Y78对葡萄糖的利用未见明显差异。以0.3,0.4,0.5,0.6 h-1的稀释率流加培养基进行连续培养,RNA质量分数最高达到6.04%,相比出发菌株,RNA质量分数提高了50.2%。由此表明通过化学处理及发酵工艺优化,提高酿酒酵母中RNA的含量,有利于工业生产RNA。
Ribonucleic acid is one kind of important biological molecules which plays an important role in the biosynthesis of protein and gene expression.Nucleotides,as their degradation products,are often used in food and pharmaceutical intermediates.For example,the uracil and its derivatives can be used for the treatment of cancer and viruses.At present,Candida tropicalis is usually acquired with high RNA yield.However,it belongs to pathogenic bacteria with a potential weakness.Saccharomyces cerevisiae which is well-adapted to industrial production owing to its tolerance to a wide spectrum of inhibitor has been widely used in food industry,which has low RNA content of about 3.0% based on the dry cell weight.To obtain a yeast mutant with high RNA content,Saccharomyces cerevisiae CGMCC NO.2448 was mutated with ethyl sulfate（DES）.Among the selected mutants that were sensitive to potassium chloride,Y78 strain was finally selected from 100 available yeast strains based on its high RNA content and favorable growth properties and the dry cell concentration of 4.5 g / L and RNA content of 5.02% were obtained.It was found that RNA content reached 5.18% during exponential phase in batch fermentation process,which was 1.5 fold more than parental strain.No apparent difference was observed in the glucose consumption rate between strain Y78 and parental strain Saccharomyces cerevisiae CGMCC NO.2448.In high-density continuous fermentation,the RNA content reached 6.04%,which was 50.2% higher RNA content than the parental strain.This study revealed that the chemical treatment and fermentation techniques were important tools for strain improving,and provided a powerful approach to improve RNA content of Saccharomyces cerevisiae for industrial production.
出处
《药物生物技术》
CAS
2013年第4期310-313,共4页
Pharmaceutical Biotechnology
基金
江苏省科技成果转化专项资金项目资助(No.BA2012090)
关键词
RNA
酿酒酵母
硫酸二乙酯
化学诱变
稀释率
连续培养
RNA
Saccharomyces cerevisiae
Ethyl sulfate
Chemical mutation
Dilution rate
Continuous fermentation
