【摘要】 目的:对小米混菌发酵过程中酵母菌对乳酸菌生长代谢的影响加以研究,并建立混菌发酵生长动力学模型。方法:以小米为生长基质,将乳酸菌和酵母菌分别纯培养和混菌培养,研究发酵液中细胞浓度、游离氨基氮(FAN)、还原糖、乳酸及乙醇含量的变化;在对Lotka-Voherra种间竞争模型改进的基础上构建混菌发酵生长模型,利用origin软件求解参数并对模型进行拟合验证。结果:加入辅助菌株酵母菌进行混菌发酵,酵母菌对乳酸菌的生长有促进作用,但对其发酵产酸没有产生显著影响,乳酸菌的存在对酵母菌有一定的抑制作用,但酵母菌主要产物乙醇的产量却显著增加;混菌发酵生长模型求得的预测值与实测值拟合较好,该模型可以有效预测混菌培养过程中乳酸菌和酵母菌的生长。更多还原

【Abstract】 Objective:The effects of yeast presence on the growth and metabolism of Lactobacillus during co-culture in millet and the kinetic model of mixed culture were studied.Methods:In a medium of millet,the characteristics of the fermentation broth including cell concentration and the contents of free amino nitrogen(FAN),reducing sugar,lactic acid and ethanol in pure culture and mixed fermentation was investigated.Moreover,the growth model of the mixed culture was established by modifying the Lotka-Voherra model and its parameter solution was gained by origin software.Then the fit of growth model was verified.Results:It was found that Lactobacillus growth was enhanced by the introduction of yeast,but yeast had no significant effect on the content of lactic acid producing by Lactobacillus.The presence of Lactobacillus inhibited the growth of yeast to some extent,whereas the production of ethanol by yeast was increased remarkably.The fit of observed and predicted cell concentration using mixed culture growth model was satisfactory,which indicated that the model could be a useful tool for predicting growth of Lactobacillus and yeast in mixed culture.更多还原