耐酸性运动发酵单胞菌酒精发酵条件的初步研究

在本实验室保藏的运动发酵单胞菌中 ,通过化学诱变和酸性平板分离 ,得到一株能在pH 4 5时进行酒精发酵的菌株 ,其酒精产量为 6 6 7g/L ,与原菌株在pH 6 5时的 6 6 7g/L相同。研究了种龄、接种量、发酵初始pH和发酵温度对细菌酒精发酵的影响。结果表明 ,在种龄为 12hr,接种量 10 % ,发酵温度 30℃～ 35℃ ,pH 4 5时 ,该菌的酒精产量达到最大为 70 1g/L。     

利用运动发酵单胞菌发酵生产酒精的研究进展

运动发酵单胞菌与传统酵母相比具有发酵速率快、糖利用率高等优点,但发酵底物范围窄.其发酵过程的生物量与葡萄糖浓度和酵母膏添加量有重要关系.细菌代替酵母称为新的发酵剂,有许多优点.详细介绍了运动发酵单胞菌发酵生产酒精的生物学特性、菌种的选育、发酵工艺和固定化技术的研究现状.     

副产物对运动发酵单胞菌酒精发酵的影响

研究了乙酸、乳酸、糠醛作为酒精发酵副产物 ,对细菌酒精发酵的影响。在发酵培养基中 ,当乙酸浓度为 1 5 g/L ,糠醛浓度为 4g/L时 ,细菌酒精产量开始减少。在乳酸浓度为 0～ 2 g/L的范围内 ,没有观察到其对细菌酒精发酵的抑制作用。运用化学渗透假说 ,对酸在细菌酒精发酵中的抑制作用进行了解释 ,同时对糠醛在细菌酒精发酵中的抑制作用进行了理论探讨     

耐酸性运动发酵单胞菌的筛选和酒精发酵条件的优化

通过酸性平板筛选,在作者所在实验室保藏的运动发酵单胞菌中,得到一株能在pH4.5时进行酒精发酵的菌株,其酒精产量为66.7g/L,与原菌株在pH6.5时的相同.通过单因素实验和正交实验,对该菌在酸性条件下的酒精发酵条件进行了优化.结果表明,在发酵温度为30～35℃,pH4.5,初糖质量浓度150g/L,酵母膏质量浓度4g/L,蛋白胨质量浓度为2g/L时,该菌的酒精产量达到最大,为71.7g/L.     

运动发酵单胞菌酒精发酵糟液的全回流技术

酒精生产会产生大量的酒糟废液,若不适当处理,将会对环境造成严重的污染。文中将细菌酒精发酵废液经过过滤后,代替拌料用水,循环用于酒精生产。回流发酵进行了8批,酒精产量没有降低,体积分数稳定在7.3％左右。发酵液残糖和最终pH也趋于稳定,分别在1.5g/L和4.0上下波动。相对于酵母酒糟回流技术,细菌酒糟回流技术所需的处理过程更简单。而且在回流中,不需要每次都添加氮源,这样可以减少发酵有害物质的积累,有利于实现酒糟滤液全回流。     

正交旋转回归试验优化木糖醇发酵培养基

利用旋转回归法研究热带假丝酵母 (Candidatropicalis)木糖醇发酵的 2个因素 :葡萄糖和酵母膏用量对木糖醇转化率的影响 ,根据木糖醇转化率依葡萄糖和酵母膏用量的回归方程分析表明 ,培养基中添加葡萄糖能提高木糖醇产物转化率 ,而酵母膏对提高产物转化率的作用不显著。研究同时表明 ,添加葡萄糖后能降低培养基中酵母膏的使用量 ,节约成本。根据回归方程寻优得出 :当木糖质量浓度 13 0 g/L时 ,葡萄糖用量 14 2 6g/L ,酵母膏用量3 40 g/L时 ,由木糖生成木糖醇的产物转化率最高     

用正交试验提高酒精生产淀粉转化率

本文报导了采用正交试验对酒精生产中淀粉转化率最佳工艺条件的确定。对影响淀粉转化糖化工艺主要因素：酶的添加量、糖化温度、醪液ｐＨ、反应时间进行了考察，并对试验数据进行了方差分析，绘制了诸因素与转化率的关系曲线。试验获得的最佳工艺条件为：ｐＨ４．０，温度６０℃，酶量１３０ｕ／ｇ，时间２０分钟。     

运动发酵单胞菌(Zymomonasmobilis)发酵乙醇的研究进展

运动发酵单胞菌(Zymomonas mobilis)是一种能够直接利用糖类(葡萄糖、果糖、蔗糖)产生乙醇的细菌微生物。相对传统发酵酒精的酵母菌而言,运动发酵单胞菌有其独特的、优越的性状特点,比如发酵乙醇代谢过程简单,发酵速度快、转化率高和耐受力强等。在工业运用方面具有潜在的应用价值(用于燃料乙醇、酶制剂以及酒类生产等)。主要对运动发酵单胞菌的乙醇代谢及其特点、运动发酵单胞菌的遗传育种、运动发酵单胞菌在工业运用方面的趋势进行综述。     

响应面法优化运动发酵单胞菌发酵面包工艺

为探究运动发酵单胞菌发酵面包的最佳生产工艺,考察发酵时间、蔗糖添加量、食盐添加量对面包感官评分的影响。通过单因素试验结合响应面方差分析优化其最佳工艺参数,并对成品面包的理化指标、质构特性及微生物指标进行检测。研究结果表明,各因素对运动发酵单胞菌面包的影响顺序为发酵时间>蔗糖添加量>食盐添加量,最佳工艺参数为发酵时间3.40 h、蔗糖添加量15.60%、食盐添加量0.80%。此时运动发酵单胞菌发酵面包品质最佳,实际感官评分为92.78。成品表面完整光洁,具有浓郁的面包香气,口感松软适口,组织内部细腻、有弹性,理化指标及微生物指标均符合国家标准。     

酒精发酵培养基优化过程中两种试验设计方法的比较研究

应用均匀设计和响应曲面设计两种设计方法对酒精发酵培养的配方进行了优化.同时,运用两种软件Minitab15和SAS9.0对所得数据进行了回归分析和结果计算.结果表明,两种设计方法所得到的培养基的配方基本一致.但是,均匀设计方法运用SAS9.0进行回归分析所用的实验次数比响应曲面法运用的试验次数较少,并且最终的乙醇产量高于响应曲面设计,所以本实验最终选择均匀设计方法,运用SAS9.0进行数据分析.     

Production of Ethanol From Maize by Zymomonas mobilis

Maize (Zea mays Ganga-5, hybrid variety) was used as a substrate for ethanol production by batch fermentation using Zymomonas mobilis. 20% solids concentration, 72 h of duration, pH 5.5 and 30°C were found most effective in yielding maximum alcohol and proved optimum for highest fermentation efficiency.     

Cosmeceutical properties of levan produced by Zymomonas mobilis

Levan, a polysaccharide that can be produced by both plants and micro-organisms, is a sugar polymer composed of fructose, with-2,6 linkages. Here, we have attempted to assess the possible use of levan produced by Zymomonas mobilis as a cosmeceutical ingredient. In service of this goal, we assessed a host of levan's properties, including its moisturizing effects, cell cytotoxicity, cell proliferation effects and anti-inflammation effects. Levan exhibited a moisturizing effect that was almost exactly the same as that evidenced by hyaluronic acid, as well as a similar cell proliferation effect in human fibroblast and keratinocyte cell lines. Moreover, in our cell proliferation test, which was conducted using bio-artificial skin constructed via 3-dimensional (3-D) culture after the induction of primary skin inflammation with 0.05% sodium lauryl sulphate (SLS), cell viability in the presence of levan (0.01 and 0.05 mg mL^–1) was determined to be higher than cell viability in the absence of levan. In our anti-inflammation test, which was also conducted using 3-D artificial skin, and which involved the measurement of a quantity of secreted interleukin-1 (IL-1), a pre-inflammatory mediator induced by SLS, we determined that the quantity of IL-1 in the 3-D artificial skin treated with 0.01 and 0.05 mg mL^–1 of levan was less than that registered in a skin sample that had been treated only with SLS. In this study, we determined that levan exerted an anti-inflammatory effect against inflammatory reactions to skin irritants, and also that levan exerted a cell-proliferative effect in bio-artificial skin, thereby indicating its potential applicability as a cosmeceutical agent.     

运动发酵单孢菌发酵生产乙醇研究进展

运动发酵单孢菌与传统酵母相比具有发酵速率快、糖利用率高等优点．但发酵底物范围窄。其发酵过程的生物量与葡萄糖浓度和酵母膏添加量有重要关系。应用固定化、共固定化技术,多菌株混合发酵,或利用基因工程技术可提高运动发酵单孢菌的发酵产酒精性能。提高发酵产乙醇量。（孙悟）     

Dough-leavening by Zymomonas mobilis and Its Application to Breadmaking

Among five strains of Zymomonas mobilis strain Z6C had the highest leavening ability in doughs containing either glucose or sucrose. Z6C most efficiently leavened the dough when it contained 5% sucrose, and this leavening ability was twice as much as that of commercial compressed yeast. At the same concentrations of NaCl, the leavening ability of Z6C was reduced more than that of baker's yeast. When comparing baked goods made with yeast, those made with Z6C had similar specific volumes, but Z6C baked goods had slight acidic flavor. Chromatographic analysis of head-space gas of yeast-leavened bread showed that two chemicals appearing in Z6C leavened bread were missing.     

雅致放射毛霉和运动发酵单胞菌混合发酵霉豆渣研究

研究雅致放射毛霉和运动发酵单胞菌混合发酵霉豆渣的条件,并在最优发酵条件下测定产品的pH值、氨基态氮含量、总粗蛋白含量及质构在发酵过程中的变化。通过正交试验确定霉豆渣发酵的最优条件为：豆渣蒸煮15min后,在100g豆渣中接入105CFU/mL雅致放射毛霉孢子悬液1.0mL及107CFU/mL运动发酵单胞菌悬液0.2mL,28℃培养3d。在发酵过程中,霉豆渣的pH值从5.12上升至8.40后缓慢下降至8.09;氨基态氮含量则先迅速上升后缓慢下降;总粗蛋白含量逐渐下降。发酵过程使霉豆渣的硬度和咀嚼性明显提高。     

用L9(34)正交试验筛选裂褶菌液体培养基

用正交设计试验方法对裂褶菌(Schinophyllum communeFr.)进行了液体培养基的筛选研究.结果表明,裂褶菌液体培养基的最适配方为:马铃薯200 g,麸皮100 g,葡萄糖30 g,酵母膏1.0 g,KH2PO45 g,MgSO4.7H2O 2.5 g,VB10.1 g,CaCO33 g,H2O 1 L.     

The effect of osmo-induced stress on product formation by Zymomonas mobilis on sucrose

The intensification of biosynthesis of fructooligosaccharides in the presence of high salt concentrations was observed during sucrose (10%) fermentation by Zymomonas mobilis 113S. A 0.6 M NaCl concentration led to an increase of oligosaccharide productivity by 3.5-fold. Sorbitol formation was increased in the presence of 0.16 M NaCl and was inhibited at highest salt concentrations. In a medium with high (65%, w/w) sucrose content the salts gave inhibitory effects on fructooligosaccharide production by lyophilised Z. mobilis cells. Influence of salts on gluconic acid and sorbitol formation under these conditions was studied. The ratio of oligosaccharides and gluconic acid productivity (Qolig./Qglucon.) was increased approximately 2 times at 1% KCl. Sorbitol formation was not significantly influenced in the presence of KCl (up to 2%).