浅谈葡萄酒生物性病害

本文总结了葡萄酒生产中常见的几种生物性病害，并结合生产实际提出了相应的防治措施．     

INDOLE-3-ACETIC ACID PRODUCTION BY GEL-ENTRAPPED BACILLUS THURINGIENSIS IN THE PRESENCE OF ROCK PHOSPHATE ORE

Bacillus thuringiensis in entrapped in k-carrageenan was capable of producing indole-3-acetic acid (IAA) in the presence of rock phosphate ore (RPO). After five repeated batch fermentation experiments, an average of 6.9 mg/L IAA was recorded in the presence of 1.5 g/L RPO and 4.7 mg/L IAA in the RPO-free control. The bacterium simultaneously solubilized phosphates with a maximum soluble P of 115 mg/L and 150 mg/L after the fourth batch cycle in 1.5 and 3.0 g/L RPO amendment, respectively. Addition of tryptophan to the media increased IAA production to 13.9 and 20.7 mg/L per batch on RPO-free and 1.5 g/L RPO-supplemented media with poor bacterial growth and RPO solubilization.     

Characteristics of an atrazine degrading bacterium and the construction of a microbial agent for effective atrazine degradation

A bacterial strain, YQJ‐6, capable of highly degrading atrazine was isolated from soil. Strain YQJ‐6 was identified as Bacillus atrophaeus based on 16S rRNA and the analysis of morphology as well as physiological and biochemical characteristics. The optimal pH value and temperature for strain YQJ‐6 to grow and degrade atrazine were 7.0–7.5 and 30–40°C, respectively. The degradation rate of atrazine (50 mg/L) by strain YQJ‐6 reached approximately 99.2% in 7 days. Strain YQJ‐6 also had a high tolerance to atrazine and could tolerate at least 1000 mg/L atrazine. In addition, strain YQJ‐6 was successfully made into a microbial agent that is easy to commercialize and can be used to treat atrazine residues in soil. The microbial agent containing the strain YQJ‐6 achieved good experimental results. It is believed that strain YQJ‐6 can be used to control atrazine pollution.     

煤炭生物絮凝絮体分形试验研究

为解决化工产品类絮凝剂的大量使用会对环境造成严重污染的问题,采用对煤炭具有良好絮凝作用的枯草芽孢杆菌作为生物絮凝剂产生菌,开展煤炭生物絮凝试验和絮体分形试验研究。通过对生物絮凝的絮体进行显微图像采集与分析,利用絮凝体的投影面积与最大长度的函数关系计算絮凝体的分形维数。研究发现,枯草芽孢杆菌絮凝剂用量和絮体分形维数与煤泥水透光率之间具有显著的相关性。研究结果表明,以絮凝体分形维数为主控指标,可以实现对枯草芽孢杆菌絮凝剂的定量控制,能够比较客观地反映煤泥水的絮凝沉降过程。     

无菌包装系统使用过氧化氢杀菌的安全性评估

综述了无菌包装系统使用过氧化氢进行杀菌的沿革及现状，包括过氧化氢杀菌安全评估中杀菌对象菌的选择、过氧化氢的杀菌性能研究、化学试剂杀菌系统的评估研究及包装材料所需杀菌强度的研究状况，为无菌包装系统的评估提供一些参考的依据。     

杆菌属蛋白酶基因的结构及其应用

本文介绍了杆菌属中蛋白酶基因的结构及其在工业、科学研究中的广泛应用。杆菌属中的蛋白酶基因具有典型的“ｐｒｅ┐ｐｒｏ┐成熟酶前体”编码特征。其中ｐｒｅ┐序列编码信号肽，ｐｒｏ┐序列编码一段为蛋白酶形成具有生物活性的合适构象所需的肽链。ｐｒｅ┐与ｐｒｏ┐序列都在蛋白酶前体从细胞中分泌出来后被切去。具有相同性质的蛋白酶即使来源于不同菌种，在基因结构上仍具有很高的同源性；而性质不同的蛋白酶，即使来自同一菌种，它们在氨基酸组成，在ｐｒｅ┐、ｐｒｏ┐序列上都存在着很大差异。克隆的蛋白酶基因可用以构建具有蛋白酶高表达活性的基因工程菌，也可被用来研究蛋白酶的结构与性能的相互关系，还可被用于构建具有特殊功能的克隆载体。     

Inhibition of Bacillus cereus spore outgrowth and multiplication by chitosan

Bacillus cereus is an endospore-forming bacterium able to cause food-associated illness. Different treatment processes are used in the food industry to reduce the number of spores and thereby the potential of foodborne disease. Chitosan is a polysaccharide with well-documented antibacterial activity towards vegetative cells. The activity against bacterial spores, spore germination and subsequent outgrowth and growth (the latter two events hereafter denoted (out)growth), however, is poorly documented. By using six different chitosans with defined macromolecular properties, we evaluated the effect of chitosan on Bacillus cereus spore germination and (out)growth using optical density assays and a dipicolinic acid release assay. (Out)growth was inhibited by chitosan, but germination was not. The action of chitosan was found to be concentration-dependent and also closely related to weight average molecular weight (M_w) and fraction of acetylation (F_A) of the biopolymer. Chitosans of low acetylation (F_A = 0.01 or 0.16) inhibited (out)growth more effectively than higher acetylated chitosans (F_A = 0.48). For the F_A = 0.16 chitosans with medium (56.8 kDa) and higher M_w (98.3 kDa), a better (out)growth inhibition was observed compared to low M_w (10.6 kDa) chitosan. The same trend was not evident with chitosans of 0.48 acetylation, where the difference in activity between the low (19.6 kDa) and high M_w (163.0 kDa) chitosans was only minor. In a spore test concentration corresponding to 10²-10³ CFU/ml (spore numbers relevant to food), less chitosan was needed to suppress (out)growth compared to higher spore numbers (equivalent to 10⁸ CFU/ml), as expected. No major differences in chitosan susceptibility between three different strains of B. cereus were detected. Our results contribute to a better understanding of chitosan activity towards bacterial spore germination and (out)growth.     

B族维生素对枯草芽孢杆菌发酵生产腺苷的影响

为了进一步提高发酵法生产腺苷的效率,该研究以枯草芽孢杆菌（Bacillus subtilis）XGL为供试菌株,通过单因素试验及正交试验探究VB1、VB3、VB5、VB7、VB12几种关键B族维生素对菌体生长及菌体产苷能力的影响。结果表明,VB1、VB3、VB5、VB7、VB12的最佳添加量分别为6.0 mg/L、5.2 mg/L、6.0 mg/L、2.4 mg/L、5.6 mg/L。此时的菌体生物量（OD600 nm值）、腺苷产量和糖苷转化率分别为74.84、53.66 g/L、33.10%,较原始培养基分别增长了8.00%、19.35%和12.59%,说明B族维生素的这种复合添加量能够较好的提高腺苷的发酵生产能力,为枯草芽孢杆菌发酵法生产核苷类物质的培养基改良提供了一定的依据。     

啤酒酿造用复合酶的研制

从一系列枯草芽孢杆菌（Ｂａｃｉｌｌｕｓｓｕｂｔｉｌｉｓ）和淀粉液化芽孢杆菌（Ｂａｃｉｌｌｕｓａｍｙｌｏｌｉｑｕｅｆａｃｉｅｎｓ）出发，经筛选和诱变选育，得到一株淀粉液化芽孢杆菌突变株（ＷＬ－ＢＡ－ｌ），该菌株经三角瓶摇瓶和２０Ｌ发酵后，在３０００Ｌ标准通风罐上进行试验，菌株发酵周期短，发酵液中β－葡聚糖酶约为１２０ｕ／ｍｌ，α－淀粉酶约１５０ｕ／ｍｌ，蛋白酶约１８００ｕ／ｍｌ．发酵液经压滤浓缩后制得液体酶制剂。