Batch and fed-batch production of butyric acid by Clostridium butyricum ZJUCB

INTRODUCTION Butyric acid has several potential applications in industry. Its applications in the foodstuffs and beverage industries are widespread. It may be used as the pure acid in the dairy industry, or in the form of esters as a food additive to increase fruit fragrance. Furthermore, butyric acid could also have some important physiological functions. For example, butyric acid esters are the character-impact flavors in tropic fruits and dairy products (Centeno et al., 2002; Watson e…     

棉花黄萎病拮抗细菌HMB-1005菌株的产芽孢条件

为提高棉花黄萎病拮抗细菌HMB-1005的芽孢形成率及芽孢数量,分析摇瓶发酵对芽孢形成的主要影响因素．通过单因素试验和正交试验对HMB-1005菌株产芽孢条件进行分析,确定最佳摇瓶发酵条件为：蔗糖1％、玉米粉2％、CaCl2·2H2O0．02％和NaH2PO4·2H2O0．2％、pH值为7．0、温度为30℃、转速为200r／min、接种量10％、种龄24h。在此优化条件下,发酵液中拮抗菌出芽率达到90％以上．     

绣球菌深层发酵工艺条件的研究

通过单因子试验和多因子正交试验,优化筛选了适于绣球菌摇瓶培养条件。结果表明,适于产菌丝体的摇瓶条件为:培养温度28℃,培养基起始pH4.5,接种量8%,摇瓶转速100r/min;摇瓶培养适于产菌丝体的最适碳氮源及其浓度分别为:可溶性淀粉2.5%,蛋白胨0.15%。适于产胞外多糖的摇瓶条件为:培养温度29℃,培养基起始pH5.5,接种量8%,摇瓶转速100r/min;摇瓶培养最适碳氮源及其浓度分别为:可溶性淀粉2.5%,蛋白胨0.25%。     

Improved elastase production by<Emphasis Type="Italic">Bacillus</Emphasis> sp. EL31410 —Further optimization and kinetics studies of culture medium for batch fermentation

An efficient culture medium producing a bacterial elastase with high yields was developed further following preliminary studies by means of response surface method. Central composite design (CCD) and response surface methodology were applied to optimize the medium constituents. A central composite design was used to explain the combined effect of three medium constituents, viz, glucose, K₂HPO₄, MgSO₄·7H₂O. The strain produced more elastase in the completely optimized medium, as compared with the partially optimized medium. The fitted model of the second model, as per RSM, showed that glucose was 7.4 g/100 ml, casein 1.13 g/100 ml, corn steep flour 0.616 g/100 ml, K₂HPO₄ 0.206 g/100 ml and MgSO₄·7H₂O 0.034 g/100 ml. The fermentation kinetics of these two culture media in the flask experiments were analyzed. It was found that the highest elastase productivity occurred at 54 hours. Higher glucose concentration had inhibitory effect on elastase production. At the same time, we observed that the glucose consumption rate was slow in the completely optimized medium, which can explain the lag period of the highest elastase production. Some metal ions and surfactant additives also affected elastase production and cell growth. Project (No. 300024) supported by the Natural Science Foundation of Zhejiang Province, China     

葡萄酒控温发酵实验研究

葡萄酒发酵过程放热量大,会使发酵介质的温度升高而影响酒的质量,因而控温发酵是酿造高品质葡萄酒的一项重要技术措施。为此,对红葡萄酒发酵过程的发热特性进行了实验研究。首先在无温控状况下进行自然发酵,研究发热量的变化关系,确定发酵过程中变化的内热源项。随后进行控温发酵实验,得到控温条件下的发酵介质温度变化曲线,并分析了控温范围等因素对发酵过程传热的影响。     

啤酒发酵中蛋白质对泡沫质量的影响

在普遍采用单罐发酵啤酒的今天，传统发酵法生产的啤酒以其品质上的优势在一些名牌大厂仍然占有一席之地。本就传统发酵啤酒过程中，对影响泡沫质量的关键因素——蛋白质的水解情况作了一些分析探讨，为有目的地改进生产工艺，提高啤酒泡沫的质量，提供了可参考的依据。     

常见担子菌发酵的类型和影响因素

本文介绍了常见担子菌发酵的类型,同时对影响常见担子菌发酵的重要因素如培养基、染菌、种子质量、pH、温度、搅拌速度等分别进行了重点阐述。     

人工接种发酵黄瓜泡菜的研究

以纯菌种发酵制备黄瓜泡菜.以植物乳杆菌B4、弯曲乳杆菌A8为发酵菌种制备黄瓜泡菜.研究了了黄瓜发酵过程中的pH、活菌数、亚硝酸盐等的变化.结果表明人工接种发酵的黄瓜泡菜与自然发酵的黄瓜泡菜相比,在第5天时有较低的pH、较高的活菌数,较低的亚硝酸盐含量.     

连续发酵生产青霉素的工艺设计

青霉素是常见的β-内酰胺类抗生素,对人体毒性很低,由发酵液提取获得。在我国一般采用分批发酵法来生产青霉素,此法耗时长、设备昂贵、人工成本高、流程复杂、产品质控难,难以满足现代工业的发展需求。本文通过对现有生产工艺的探讨,对其进行改进,为青霉素生产工业设计了一套崭新的连续发酵工艺。     

耐高温乳酸菌的筛选

通过初筛、复筛,获得一株耐高温且产酸能力较强的菌株Y5,对该菌株进行了形态学和生理生化特性鉴定,确定此菌株为乳酸茵．通过单因素试验和正交试验确定菌株Y5的最佳产酸条件：发酵温度为55℃,转速为60r／min,接种量为7％,装液量为100mL．