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以白酒糟为基质进行酵母培养物的研究

Research on Yeast Culture Using Distiller’s Grains as the Substrate

作者: 专业:微生物学 导师:梁运祥 年度:2010 学位:硕士  院校: 华中农业大学

Keywords

Yeast culture, White distiller’s grains, Density solid-state fermentation, Yeast autolysis

        酵母培养物是由酵母菌在现代发酵工艺控制下采用液、固态相结合或直接在固体培养基上发酵后连同固体基质一起加工制得的产品,它是一种集保健和营养等多重功效为一体的绿色微生态饲料添加剂。目前已有许多国外产品进入我国,但价格十分昂贵。为降低酵母培养物的生产成本,并实现白酒糟的资源化无污染化利用,本课题以廉价的白酒糟为主要基质,接种酿酒酵母,首先开展酵母高密度固体发酵的研究,确定了最佳培养条件和生产工艺,接着借鉴液体啤酒酵母泥的自溶方法,在此固体基质上进行酵母自溶处理,摸索酵母在白酒糟固体培养基中增殖后的最佳自溶条件,最终确定了在实验室条件下以白酒糟为基质生产酵母培养物的工艺流程为:250ml三角瓶装入干白酒糟10g,加入干糟质量4%的白酒糟发酵专用酶制剂,按0.7亿/克干糟的量接入活化后的酵母,调整酒糟的含水量为45%-50%,封口膜封口后于30℃恒温箱中发酵培养,培养至45h和51h各补加混合营养液2ml(以干糟质量的8%添加糖蜜,以0.5gN/kg干糟的量添加尿素),摇匀分散,自发酵起始每隔12h翻料一次至72h固体发酵结束,然后以稀硫酸调整固体酒糟基质初始pH为6,向其中添加助溶剂:6%(w/w湿糟)的NaCl溶液,0.04%(w/w湿糟)木瓜蛋白酶溶液以及9%(v/w湿糟)体积分数为95%的助溶剂无水乙醇,控制助溶剂添加总体积与酒糟干基总质量的体积质量比为1:1,搅拌分散,保持55℃自溶36h,而后烘干粉碎制得成品。经过高密度发酵后酵母总数约40亿/g干糟,自溶处理后产品氨基酸态氮含量达到3.83mg/g干糟。
    The yeast culture is under the control of modern fermentation process, adopting the method liquid and liquid-solid processing to produce the product,it is a green micro ecology feed additive which has multiple effects such as health care and nutrition, etc. At present,many foreign products have entered our country, but the price is very expensive.In order to reduce the cost of producing yeast culture and realize the reclamation and free from pollution of the white distiller’s grains,we use low-cost white distiller’s grains as main substrate and inoculate Saccharomyces cerevisiae, firstly by adopting yeast density solid-state fermentation, we obtain the optimal culture conditions and production craft,then learn from the autolysis methods of the beer yeast slurry,we carry on yeast autolysis in this solid substrate and find the best conditions of yeast autolysis.Finally we find the laboratorial technological process of producing yeast culture using distiller’s grains as the substrate:weigh 10g distiller’s dried grains and then put into 250 ml conical flask, adding dedicated enzymic preparations for white distiller’s grains fermentation which occupying 4% of the quality of distiller’s dried grains, inoculum 0.7 million activated yeast per kilogram distiller’s dried grains, adjust the water content of distiller’s grains to 45%-50%,take the flasks into 30℃incubator to cultivate after sealing,training to 45h and 51h, respectively add 2ml nutrient solution to the substrate(add molasses which occupying 8% of the quality of distiller’s dried grains and urea which has 0.5gN/per kilogram distiller’s dried grains), shake up and disperse, at intervals of 12h reverse the material until the 72h fermentation process is complete. And then, adjust initial pH of the solid-state substrate to 6 by dilute sulphuric acid,add autolysis promoter:6% NaCl solution(w/w distiller’s wet grains),0.04% papain solution(w/w distiller’s wet grains) and 9% absolute ethyl alcohol(v/w distiller’s wet grains), control the ratio of total volume of autolysis promoter and the total quality of distiller’s dried grains to 1:1, stir and disperse, maintain 55℃autolysis 36h and then dry and crush into finished product. After yeast density solid-state fermentation,the number of yeast can eventually reach to 4 billion per kilogram distiller’s dried grains,after autolysis,the ammoniacal nitrogen can reach to 3.83 mg per kilogram distiller’s dried grains.
        

以白酒糟为基质进行酵母培养物的研究

摘要7-8
Abstract8-9
1 前言10-21
    1.1 酵母培养物的概念10
    1.2 酵母培养物的研究历史10-11
    1.3 酵母培养物的营养特性11-12
    1.4 酵母培养物的功能及其作用机制12-16
        1.4.1 改善胃肠道菌群结构,提高动物生产性能12-14
        1.4.2 补充营养,改善消化功能14
        1.4.3 提高机体免疫力及抗病力14-15
        1.4.4 吸附霉毒,改善饲料品质15
        1.4.5 着色效应15
        1.4.6 保护环境15-16
    1.5 酵母培养物的应用效果16-18
        1.5.1 应用于反刍动物16-17
        1.5.2 应用于单胃(猪、禽)动物17
        1.5.3 应用于水产养殖17-18
    1.6 白酒糟的营养价值及应用现状18-20
    1.7 课题的立题依据和目的及意义20-21
2 材料与方法21-31
    2.1 实验材料21-22
        2.1.1 原料与设备21
        2.1.2 菌种21-22
        2.1.3 培养基22
    2.2 实验方法22-31
        2.2.1 酵母细胞活化方法22
        2.2.2 酵母细胞计数方法22
        2.2.3 氨基酸态氮含量的测定22-24
        2.2.4 酵母菌活性的检测24-25
        2.2.5 固体发酵条件的优化筛选25-26
        2.2.6 酿酒酵母生长曲线的测定26
        2.2.7 固体发酵中间补料的方法26
        2.2.8 固体发酵工艺的优化26-27
        2.2.9 最佳自溶条件的选择27-30
        2.2.10 数据处理30-31
3 结果与分析31-53
    3.1 固体发酵条件的优化筛选31-35
        3.1.1 三角瓶装料量的确定31
        3.1.2 白酒糟发酵专用酶制剂添加量的确定31-32
        3.1.3 初始水分的确定32-33
        3.1.4 接种量的确定33
        3.1.5 初始pH的确定33-34
        3.1.6 发酵温度与发酵时间的确定34-35
    3.2 固体发酵工艺的优化35-41
        3.2.1 补料时间的确定35-39
        3.2.2 补料种类的确定39-40
        3.2.3 补料量的确定40-41
        3.2.4 二次补料工艺41
    3.3 固体发酵条件及工艺小结41-42
    3.4 最佳自溶条件的确定42-53
        3.4.1 自溶过程中酵母形态变化42-43
        3.4.2 助溶剂的选择43-44
        3.4.3 自溶时间的选择44-45
        3.4.4 自溶初始pH的选择45-46
        3.4.5 自溶温度的选择46-47
        3.4.6 自溶加水比的选择47-48
        3.4.7 助溶剂无水乙醇加量的选择48-49
        3.4.8 加盐量的选择49-50
        3.4.9 加酶量的选择50-51
        3.4.10 酵母自溶条件正交实验结果51-53
    3.5 最佳自溶条件小结53
4 总结与讨论53-57
    4.1 总结53-54
    4.2 讨论54-57
        4.2.1 本课题创新点54
        4.2.2 本课题有待完善的部分54-55
        4.2.3 未来研究方向55-57
参考文献57-63
致谢63-64
附录64
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