【作者】 王娜；

【导师】 李冀新；

【作者基本信息】 石河子大学 ， 农产品加工及贮藏工程， 2010， 硕士

【摘要】 甜高粱又称为糖高梁,其茎秆汁液丰富、含糖量高,是一种优良的生物能源。本文经过对其茎秆汁液的营养成分研究分析,发现甜高粱汁中含有酵母菌生长和发酵所必需的各种主要营养成分,完全能够满足酒精酵母的生长和发育的要求,因此甜高梁汁液较适宜做为发酵生产燃料乙醇的原料。本文利用自然选育法,从大自然中分离筛选适合以甜高粱汁液为原料发酵制备燃料乙醇的高产酒精酵母。共从来源不同的基质中分离得到165株酵母菌,经初筛、复筛和酒精发酵试验,最终获得五株适宜甜高梁为原料,可进行酒精发酵的高产酵母菌株。经单因素试验和四因素三水平正交试验确定了这五菌株的酒精发酵工艺。各供试酵母菌株的最佳发酵条件组合为：酵母菌G中2—5：适宜发酵温度为34℃；适宜发酵pH值为5.1；适宜发酵接种量为6.5%；汁液糖锤度为19Brix。酵母菌G中3—2：适宜发酵温度为33℃：适宜发酵pH值为5.1；适宜发酵接种量为6.5%：汁液糖锤度为19Brix。酵母菌G后1—3：适宜发酵温度为32℃；适宜发酵pH值为5.1；适宜发酵接种量为4.5%；汁液糖锤度为19Brix。酵母菌s中1—1：适宜发酵温度为36℃；适宜发酵pH值为5.1；适宜发酵接种量为6.0%；汁液锤度为19Brix。酵母菌株S中4—1：适宜发酵温度为33℃；适宜发酵pH值为5.1；适宜发酵接种量为6.5%；汁液锤度为19Brix。根据五株酵母在各自的最佳发酵条件下发酵后数据,发现菌株G中3—2是五株供试酵母中的最终优势菌株。将其做为最终筛选出来的高产酒精酵母,与商业酵母丹宝利进行对照实验。由此得出结论：白选酵母菌G中3—2与商业菌株丹宝利对照而言,自选菌株与对照菌株的蒸馏酒精度大体相当；而自选菌株发酵后的残糖量比对照菌株残糖量稍高；自选菌株的发酵高峰较对照菌株推迟了近8h,其发酵时间也略为延长；自选菌株的接种量也比对照丹宝利酵母要高。本论文还对自选酵母菌株G中2—5的一些生长、发酵特性做了研究,其最佳生长温度为28℃；适宜发酵温度为32℃；适宜发酵pH值为5.1；适宜发酵接种量为6.0%；适宜汁液糖锤度为19Brix；发酵高峰期在24—32h：可利用葡萄糖、麦芽糖、蔗糖进行发酵,而对乳糖和淀粉则无发酵能力。更多还原

【Abstract】 Sweet sorghum is also known as sugar sorghum. Because of its rich stem juice and its high sugar content, sweet sorghum is a good bio-energy resource. We analyzed the nutritional content of its stalk and found that sweet sorghum juice containing all major nutrients for yeast growth and fermentation, so it can completely meet the requirements of alcohol yeast to growth and development. so sweet sorghum juice is more appropriate as a raw materials to producing fuel ethanol.In fermentation industry, select high-quality and high-yield strains of micro-organisms is the basis and key job. We use natural breeding methods, isolated yeast strains from nature suitable for fermentation of sweet sorghum juice, as the raw material prepared by high alcohol fuel ethanol yeast. And 165 strains of yeast are isolated from different matrix and sources.Through preliminary screening,the second screening and alcohol fermentation tests, ultimately obtain five yeast strains which can be produce high alcohol fermentation and suitabled sweet sorghum as raw material,We test these five strains of alcohol fermentation through single-factor test and the four factors and three level orthogonal. The yeast strains tested the combination of the best fermentation conditions:yeast G中2-5:its suitable fermentation temperature is 34℃,its suitable fermentation is pH=5.1.,its suitable fermentation inoculum is 6.5% and juice brix of sugar is 19Brix. Yeast G中3-2:appropriate fermentation temperature is 33℃; suitable fermentation pH value of 5.1; suitable fermentation inoculum is 6.5%; juice sugar brix isl9Brix. The yeast G后-3:suitable fermentation temperature is 32℃, suitable fermentation is pH=5.1,suitable fermentation inoculum is 4.5%,and its juice brix of sugar is 19Brix. The yeast S中1-1:appropriate fermentation temperature is 36℃, suitable fermentation pH value is 5.1; suitable fermentation inoculum is 6.0% and its juice brix is 19Brix. The yeast strain S. 4-1:suitable fermentation temperature is 33℃, suitable fermentation is pH=5.1, its suitable fermentation inoculum is 6.5%, and appropriate juice brix is 19Brix.According to five yeast fermentation in their best conditions of fermentation data, we found that strain G 3-2 is the best final yeast in these five tested yeast strains. To filter out as the ultimate high alcohol yeast, and commercial yeast control experiments carried out Dan Polly. Come to the conclusion:in the 3-2 choice with commercial yeast strains G Dan Polly control, the choice of strains and control strains the same amount of distilled alcohol; the choice of residual sugar after fermentation strains of residual sugar than the control slightly higher volume; optional peak strain than in the control of fermentation strains delayed nearly 8h, slightly extending the fermentation time; optional inoculum strains than the control yeast Dan Polly higher.The paper also studied the final yeast strain G+2-5 on some growth, fermentation characteristics.And the result is:its optimum temperature is 28℃, its suitable fermentation temperature iss 32℃and its suitable fermentation is pH=5.1, suitable fermentation inoculation is 6.0%; appropriate brix sugar juice as 19Brix, its fermentation peaked at 24- 32h; It can ferment use of glucose, maltose and sucrose, but can not use lactose and starch to fermentation.更多还原