餐厨垃圾生物制氢研究进展

利用餐厨垃圾进行生物制氢,不仅可解决餐厨垃圾的处置问题,而且可以产生清洁的氢能,已成为当前国内外学者研究的热点之一。了解了餐厨垃圾产氢机理及底物特性、工艺条件、产氢茵种、反应器类型等应用化技术在餐厨垃圾制氢中的应用现状。展望了餐厨垃圾制氢的研究应针对高效混合产氢菌种的选育和改造、各种生态因子对餐厨垃圾产氢茵群影响的研究．并进行新的餐厨垃圾制氢工艺和高效、规模化的餐厨垃圾生物制氢反应器的开发。     

重组毕赤酵母培养基碳源的选择

目的：对毕赤酵母重组菌GS115-Ch—Glu菌种进行发酵脱毒条件的优化,为大规模发酵重组毕赤酵母获得高表达目的蛋白奠定基础。方法：以毕赤酵母重组菌为实验菌株,分别以葡萄糖、乳糖、玉米淀粉、蛋白胨、甘油、玉米淀粉＋甘油为碳源,研究不同碳源对菌株细胞生长的影响。结果：毕赤酵母重组菌的最适碳源为玉米淀粉,最适浓度为2．5％。     

现代发酵工程展望

介绍了微生物工程的概念、发展史,现代发酵工程的特点、操作步骤和发酵方式,以及现代发酵工程技术的应用现状,并对现代发酵工程技术的未来进行了展望.     

Phenolic profile of jujube fruit subjected to gut microbiota fermentation and its antioxidant potential against ethyl carbamate-induced oxidative damage

Objective: To evaluate the composition of bioactive substances and the antioxidant effects of jujube fruit under gut microbiota fermentation(GMF), and the inhibitory effect on cytotoxicity caused by ethyl carbamate(EC). Methods: Changes in the contents of flavonoids, polyphenols, total sugars, and reducing sugars of jujube fruit after GMF(0, 2, 6, 12, 24, and 48 h)were determined. The oxidation resistance of fermented jujube fruits(from 0 to 48 h fermentation) was evaluated using in vitro2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS) and ferric reducing antioxidant power(FRAP) assays. Inhibitory effects of 48 h-fermented jujube fruit at various concentrations(0.25, 0.50, 1.00, and 2.00 mg/m L) on EC-treated toxicity and DNA damage of Caco-2 cells were estimated using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide(MTT)and nuclear staining assays, respectively. Effects of different concentrations of jujube fruit on EC-treated Caco-2 cells' intracellular reactive oxygen species(ROS), glutathione(GSH) levels, and mitochondrial membrane potential(MMP) were also evaluated. Results: Jujube fruit has rich bioactive components after GMF and shows strong antioxidant capacity. Fermented jujube fruit can inhibit the cytotoxicity and DNA damage of Caco-2 cells caused by EC and reduce intracellular ROS generation, as well as restoring GSH and MMP. Conclusions: Fermented jujube fruit extracts produced by GMF still contain biologically active substances which retain biological activity and antioxidation capabilities.     

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。     

玉米淀粉生料发酵酒精工艺条件的研究

玉米是黑龙江省的主要农作物之一,玉米的深加工利用是提高其产值的重要手段,本研究利用酶解玉米淀粉生料发酵生产酒精,对其发酵条件进行优化,得到玉米淀粉发酵酒精的最佳工艺条件:料水比1∶4、糖化酶加量为160u·g-1、发酵温度为34℃,干酵母加量为0.75%、pH为4.5、发酵时间6d,发酵酒精度为13.9%vol。     

亲水性单胞菌几丁质酶发酵工艺优化

首次报道从温州浅海海水中筛选得到的一株产几丁质酶的亲水性单胞菌属细菌(Aeromonas hydrophila sp.)。在探索了碳、氮源和环境因子对细菌产酶影响的基础上,利用均匀设计法优化得到了较佳的产酶发酵培养基配方(g/L):胶体几丁质5.0,蛋白胨12.0,尿素2.0,MgSO4 0.5,K2HPO4 0.3,NaCl5.0,初始pH 6.5。在接种量6%,培养温度28℃,180 r/min的较佳工艺下振荡发酵5 d,该菌产酶活力达到1.89 U/mL。     

大型发酵机多层搅拌流固耦合仿真分析

基于有限元法对流固耦合作用下的刀具转速开展搅拌效果及受力变形分析。在流体动力学分析中,采用示踪剂浓度法、多重参考系法研究转速对搅拌效果的影响。将静力学和动力学模块进行连接搭建,研究不同转速下的刀具受力变形情况,获得搅拌叶片的安全转速取值范围。结果表明：在达到临界转速前,所需混合时间对转速的变化敏感,搅拌桨的受力和变形也随转速的增加而增大;从流场、混合时间、应力和应变的角度综合考虑,搅拌转速设置为200 r/min时综合指标更高。