Effect of temperature on batch elastase production by <Emphasis Type="Italic">Bacillus</Emphasis> sp. EL31410

The production of elastase by Bacillus sp. EL31410 at various temperatures was investigated. In order to study the effect of temperature on elastase fermentation, different cultivation temperatures, ranging from 39 °C to 28 °C, were evaluated in shake flask. The result indicated that 37 °C was best for cell growth at earlier stage; while maximum elastase activity was obtained when the cells were cultivated at 30 °C. This result was verified by batch fermentation in 5-L bioreactor under 37 °C and 30 °C temperature, respectively. The specific cell growth rate at 37 °C was higher than that at 30 °C during earlier stage of cultivation. The maximum value [5.5 U/(h·g DCW)] of elastase formation rate occurred at 24 h at 30 °C compared to 4.6 U/(h·g DCW) at 30 h at 37 °C. Based on these results, two-stage temperature shift strategy and oscillatory temperature cultivation mode were evaluated in the next study. When compared to single temperature of 37 °C or 30 °C, both two-stage temperature shift strategy and oscillatory temperature strategy improved biomass but did not yield the same result as expected for elastase production. The maximum biomass (both 8.6 g/L) was achieved at 30 h at 37 °C, but at 42 h using two-stage temperature cultivation strategy. The highest elastase production (652 U/ml) was observed at 30 °C in batch process. It was concluded that cultivation at constant temperature of 30 °C was appropriate for elastase production by Bacillus sp. EL31410. Project (No. 20276064) supported by the National Natural Science Foundation of China     

基于OBE的PLC实践课程教学设计研究

该文从工程教育专业认证毕业要求出发,以PLC课程设计课题"MSBR池控制系统设计"为例,贯彻工程教育专业认证OBE理念,对课程设计的教学环节进行教学设计。分析和研究工程的技术和运行管理现状,分析工艺流程和生产运行需求,通过技术经济分析,确定设计方案。从复杂工程系统中提炼出子系统和复杂工程问题,学生在实践过程中提升工程设计能力。设计成果证明,学生工程能力提高显著。     

基于应用型人才培养需求的教学课程整合与优化

“生物反应器与发酵工程”与“生物制药设备与分离纯化技术”是我校生物技术专业学开设的两门应用型专业课程。这两门课的理论教学内容与前期基础课程存在诸多交叉重叠,导致实验课时不足和实验课教学内容连贯性差等问题,严重影响教学效果。根据近年来对这两门课程的教学实践与体会,结合两门课程所存在的问题和应用型人才培养的需求,将两门课整合为一,对理论教学内容、实验教学内容、实践教学环节以及考核方式等方面进行整合优化,提高教学质量和教学效率。     

Influence of medium components on elastase production using crude sources by Bacillus sp. EL31410

A newly isolated strain EL31410, producing elastase (E.C3.4.4.7) with high elastolytic activity was identified as Bacillus sp. In the medium optimization, it was found that wheat bran and soybean flour hydrosate were the best crude carbon and nitrogen source for enzyme production, respectively. Addition of corn steep flour can affect the bacterium growth and elastase production. A fractional factorial design was applied to study the main factors that affect the enzyme production, and central composite experimental design and response surface methodology were adopted to derive a statistical model for the effect of wheat bran and soybean flour hydrosate on elastase production. The experimental results showed that wheat bran had positive effect but soybean flour hydrosate had negative effect, on enzyme production. An initial concentration of 3.4%(w/v) wheat bran and 9.4%(v/v) soybean flour hydrosate were found to be optimal for enzyme production in batch culture. The time course of elastase production in the optimized medium composition was also described.     

木糖渣生物转化产乳酸的初步研究

用两步法将玉米棒芯生产木糖后剩下的废物木糖渣生物转化为乳酸,先用纤维素酶水解木糖渣生成葡萄糖;然后用乳酸菌发酵葡萄糖产乳酸。纤维素酶水解的最佳条件为pH=4．8,水解温度50℃,水解时间48h,此时葡萄糖含量可达41．76g·L-1。混合菌比例5：1,温度40℃左右,时间32h为乳酸菌发酵产乳酸的最佳条件,温度42C时发酵液中乳酸含量可达2．12g·L^-1。     

高职《发酵工艺》课程教学改革的探索

从剖析高职食品生物技术专业的人才培养目标定位、课程体系构建入手,对《发酵工艺》课程的课程定位、课程目标和课程内容以及教学模式进行探索。     

响应面法优化纳豆激酶液体发酵条件的研究

为了提高纳豆激酶的酶活力,本研究借助Minitab软件,采用Plackett-Burman试验设计方法和响应面分析方法对保存的枯草芽孢杆菌纳豆亚种（Bacillus subtlis natto。简称纳豆菌）-NT207进行了液体发酵条件的优化。首先通过Plackett-Burman方法对11个相关影响因素的效应进行评价,并筛选出有显著正效应的木糖浓度和有显著负效应的接种量、K2HP04浓度等三个因素,然后利用响应面分析方法确定了上述三个因素的最佳工艺参数。实验结果表明,在优化后的发酵条件下,纳豆激酶的产量为1504．51U／mL,比优化前提高了130．3％。     

谷氨酸发酵生产工艺冷凝水的利用探讨

在味精清洁生产工艺中,四效蒸发浓缩谷氨酸超滤清液,以及三效浓缩等电结晶母液,所得的蒸发凝结水（简称工艺冷凝水PCO）,因COD、氨氮稍高而不能直接排放。为解决这一环保问题并节约水资源,本文研究了将PCO作为配料水应用于味精生产以及用于部分取代超滤的清洗用水的可行性。通过与自来水进行比较,考察了其对液化、糖化和发酵过程及超滤清洗效果的影响。     

Bacillus Megaterium在Vc二步发酵中伴生活性初步研究

在维生素C二步发酵中,Bacillusmegaterium作为伴生菌能有效促进Gluconobacteroxydans的生长和产VitaminC的前体 2 酮基 L 古龙酸(简称 2 KLG)。实验室利用低能离子对出发菌BP5 2进行诱变选育,获得一株B.megaterium突变体GB82,此突变体与G.oxydans组成的混合体系GAB,比原始混合体系 2 980产酸水平高 1 0个百分点以上。比较研究了GB82与原始B.megateriumBP5 2分泌的生物活性物质对产酸菌G.oxydans产 2 KLG的影响,据此提出此活性物质可能是某种蛋白,且此蛋白在极端条件下会部分失活的观点;并且通过RandomAmplifiedPolymorphicDNA(RAPD)分析揭示了低能离子注入造成的二者基因水平上的差异。     

果酸乳酸饮料发酵试验

本文研究了以番茄和胡萝卜作为主原料,与牛奶相结合的发酵乳酸饮料的工艺流程及操作方法。以五因素两水平正交试验确定最佳工艺条件为:以保加利亚乳杆菌和嗜热链球菌1:1混合菌种接种进行乳酸饮料发酵,番茄和胡萝卜混合汁添加量50%,接种量5%,蔗糖添加量10%,发酵温度43℃、时间11小时,5℃低温下后熟2天。即得原料来源丰富,营养价值极高的果蔬汁发酵乳酸饮料。