【作者】 王学锋；

【导师】 刘延琳；

【作者基本信息】 西北农林科技大学 ， 发酵工程， 2010， 硕士

【摘要】 本试验以我国本土优选的酿酒酵母Saccharomyces cerevisia LFN518为试验材料,研究了该菌株增值的最适培养基和培养条件,构建了该菌株的生长动力学模型和基质消耗动力学模型,确定了真空冷冻干燥最佳的保护剂配方,进一步制备了符合国标的活性干酵母粉,并对制备的活性干酵母粉的复水条件进行了初步的研究。主要的研究结果如下:以摇瓶发酵为基础,在尽量提高供试酿酒酵母菌株生物量的前提下,采用单因素与响应曲面相结合的设计方法,对影响优选酵母菌株S. cerevisia LFN518生物量的培养基相关的主要成分进行了优化,然后建立数学模型,通过响应曲面分析得到最优的酵母培养基配方为:麦芽糖31.6g/L、酵母浸粉18.1g/L、磷酸氢二钾8.0g/L、硫酸镁12.0g/L、氯化钙6.0g/L,维生素母液6.0mL/L。优化后,酿酒酵母的生物量达到8.124g/L,比优化前的6.25g/L提高了29.94%。以S. cerevisia LFN518的生物量为指标,采用正交试验设计对该酵母最适生长条件进行研究,结果表明,该酵母的最适培养条件为:温度28℃、初始pH 4.6、转速170r/min、装液量为120mL(500mL三角瓶)。在S .cerevisia LFN518最适培养基和培养条件研究的基础上,进一步构建了该菌分批培养的生长动力学模型和基质消耗的动力学模型。采用单因素试验和正交试验相结合,得到了S. cerevisia LFN518真空冷冻干燥最优保护剂配方(g/L):葡萄糖60,乳糖100,脱脂奶粉100。采用单因素试验和正交试验相结合,得到了S. cerevisia LFN518最佳的复水活化条件为:料液比(g/mL)1: 40,葡萄糖的浓度4%,复水活化的温度为39-41℃。在最佳的复水条件下得到的复水时间为35-40min。更多还原

【Abstract】 Using indigenous Saccharomyces cerevisiae LFN518 in Xinjiang as the expremental material, the experiments have systematically studied the most appropriate culture medium and culture conditions of the strain, have built the growth and substrate consumption kinetics models of this strain and fixed the optimal protectants recipe of the vacuum freeze-drying, then prepared the active dry wine yeast which complied with the national standard further, at last the initially study were done for the rehydration conditions of active dry wine yeast. The main results are as follows:The experiments based on shaking flask and the premise of increasing the biomass of Saccharomyces cerevisia as much as possible, optimizing the main relative components of the medium which have the impacts on the biomass of the selected yeast Saccharomyces cerevisia LFN518 by using the method of combination of single factor and response surface, then eastablished a mathematical model, by analyzing the response surface, the optimal medium was obtained finally: maltose 31.6g / L, yeast extract 18.1g / L, potassium hydrogen phosphate 8.0 g / L, magnesium sulfate 12.0g / L, calcium chloride 6.0g / L, vitamin liquor 6.0mL/L, the biomass of Saccharomyces cerevisiae was 8.124g / L which increased by 29.94% than 6.25g / L before.Taking the biomass of S. cerevisia LFN518 as the index, the most suitable conditions of the yeast growth were studied by using the orthogonal experiment, the results show that the most suitable cultivation conditions of yeast are: temperature 28℃, initial pH4.6, rotation rate 170r/min, medium volume 120mL(triangular flask 500mL).On the basis sdudy of the most suitable medium and cultivating conditions on S. cerevisia LFN518, the kinetics model of growth and matrix consumption of the batch culture were constructed.By the combination of the single factor test with orthogonal experiment design, it has abtained the optimal protectants of S. cerevisia LFN518’s vacuum freeze-drying (g/L): glucose 60 g/L, lactose100 g/L, skim milk powder100 g/L.By the combination of the single factor test with orthogonal experiment design, the best conditions of the rehydration and activation for S. cerevisia LFN518 were obtained: the ratio of solid to liquid (g / mL) 1: 40, glucose concentration 4%, temperature of the rehydration and activation 39-41℃. The rehydration time was 35-40min under the best conditions of the rehydration.更多还原