【作者】 刘杰；

【导师】 杜风光； 宋安东；

【作者基本信息】 河南农业大学 ， 微生物学， 2009， 硕士

【摘要】 参考天冠集团真空抽酒生产线,自制一个乙醇发酵与真空分离小型反应器,在此基础上,研究了适用于反应器的培养基条件,抽酒工艺参数,负压对酵母生理生化的影响;针对生产线抽酒过程中酸度会升高的问题,对杂菌进行了好氧、厌氧平板观察和变性梯度凝胶电泳(DGGE)分析。主要结论如下:(1)适用于设备参数和工艺参数的发酵培养基条件:水:玉米:木薯=4:1:1,种子液浓度为1g干酵母/100水,接种量10%。这样的培养基条件可以保证酒度较高的前提下物料不会阻塞设备管道,且发酵结束时残总糖较低。(2)最佳抽酒工艺条件:10°左右的酒度开始抽,抽酒压力为5kpa个大气压,抽酒温度40℃,抽酒过程中补料对发酵有促进作用;温度、乙醇、压力对发酵影响的试验结果证明了这一工艺条件的正确性。(3)通过平板和显微观察,发现负压对酵母活性、形态有影响;负压对发酵性能影响的试验中,抽酒减少了酒精抑制,增加了耗糖速度,抽样乙醇产量、产率、得率分别是74.72g/L、1.067g/(L.h)、0.372g/g,对照乙醇产量、产率、得率分别是74.4g/L、1.06g/(L.h)、0.377g/g;抽压过程中甘油以及和能量代谢相关的副产物增加,发现有一部分糖消耗掉转化为菌体的维持能,用excel中的规划求解工具计算出的代谢流分布结果与此一致;根据发酵结果,对菌体生长,糖消耗,co2生成,乙醇生成进行了曲线拟合。(4)好氧,厌氧平板观察都发现有杂菌菌落;结合取样时生产化验数据,DGGE分析得出酸度高可能和b、c、e条带所代表的菌有关。更多还原

【Abstract】 Reference to the vacuum -pumping line in tianguan enterprise group,we maked a small similar reactor, on which we did some experiments on medium condition suited to the reactor, process parameters during pumping and physiological and biochemical effects of yeasts in negative pressure. according to the rise of acidity,we did some aerobic、anaerobic plate, and DGGE analysis.The main conclusions of this thesis included the following four parts:Firstly, the following was of the conditions of the fermentation medium fit for equipment and process parameters: The proportion of water、corn and cassava is 4:1:1; The concentration of seed liquid is 1g dry yeast/100ml water; The inoculation amount is 10%.This conditions can make sure materials don’t block pipes, alcohol degree is high and residual sugar is low.Secondly, the following was of the optimal conditions of pumping alcohol:5kpa of atmospheric pressure, 40℃of pumping temperature,10 alcohol degree of begin pumping period. The orthogonal experiment result of temperature、atmospheric pressure and alcohol proved the process conditions right.Thirdly, By platel and microscopic observation,the effect of negative pressure to yeast’activity and shape was found; Pumping alcohol decreased the Inhibition of alcohol, increased the speed of consuming sugar, The production rate、yield rate and gain rate of pumped sample were 74.72g/L、1.067g/(L.h) and 0.372g/g, While the production rate、yield rate and gain rate of control were 74.4g/L、1.06g/(L.h) and 0.377g/g;the yield of glycerol and by-products related to energy metabolism rised during pumping, some sugar transformed into somatic maintenance energy,which was proved by metabolic flux; On the results of fermentation experiment,yeast fermentation kinetic model was eastablished.Fourthly, mixed bacterium colony were found on plates, The reason why acidity was high may be related to the colony b、the colony c and the colony e.更多还原