一株耐高温β-胡萝卜素降解菌的筛选及发酵工艺优化

A Type of High-temperature Resistance Screening and Preparation Optimization ofβ-carotene Degrading Bacterium

以提升烟叶香韵为目的,对4株产香酵母菌进行发酵培养,通过产香感官评价、酶活分析、烟叶发酵成分分析(GC-MS法),筛选得到1株β-胡萝卜素降解产香酿酒酵母(Saccharomyces cerevisiae)SC35。方法:①4株酵母菌发酵产香效果感官评价;②CS35菌株β-胡萝卜素降解效果分析、样品萃取及GC-MS靶向测试分析;③酶活测定、酶促反应体系研究;④菌株SC35发酵工艺优化及响应面优化。SC35在70℃高温环境下能有效加速β-胡萝卜素的降解,降解产物为1,3-环己二酮、氧化异佛尔酮、β-紫罗兰酮等,通过单因素试验和响应面法优化菌株SC35的最佳培养基配方中各组分添加量依次为葡萄糖2.01%,NaNO20.20%,K2HPO40.10%,MgSO40.05%,FeSO4·7H2O 0.001%,KCl 0.05%;最佳发酵条件为发酵温度27.65℃,发酵时间72 h,接种量0.99%,摇床转速140 r/min,装液量100 mL/250 mL,pH值5.5(自然)。采用优化后发酵工艺SC35粗酶液降解效率可达86%以上。

To improve the aroma of tobacco leaves,four aroma-producing yeasts were cultured,and the aroma-producing sensory evaluation,enzyme activity analysis and fermentation composition analysis(GC-MS)were carried out,aβ-carotene degrading Saccharomyces cerevisiae strain SC35 was screened.Methods:①sensory evaluation of aroma production by four strains of Saccharomyces cerevisiae;②analysis of beta-carotene degradation,sample extraction and GC-MS targeting test;③enzyme activity determination,enzyme reaction system study;④optimization of fermentation process and response surface of strain SC35.SC35 could effectively accelerate the degradation ofβ-carotene at 70℃.the degradation products were 1,3-cyclohexanedione,isophorone,β-gamma-ionone,etc.,the optimal medium formulation of strain SC35 was optimized by single factor and response surface methodology:glucose 2.01%,NaNO20.20%,K2HPO40.10%,MgSO40.05%,FeSO4·7H2O 0.001%,KCl 0.05%;The optimum fermentation conditions were as follows:temperature 27.65℃,period 72 hours,inoculation amount 0.99%,rotating speed 140 r/min,filling volume 100 mL/250 mL,pH 5.5(natural).The degradation efficiency of SC35 crude enzyme could reach more than 86%by the optimized fermentation process.