一种简单有效的黄原胶菌种保藏方法

在黄原胶的连续和分批发酵中都观察到菌株的变异现象, 给科研、生产带来极大困扰,这主要是由于菌种的保藏方 法不当引起的。我们采用矿物油法对黄原胶菌种进行长 期保存,多年来实验结果表明,此法简单易行,保存菌种 存活率高,最长保存时间可达5-6年。菌种保藏5年后, 经测定,摇瓶发酵液平均粘度为原菌种的81.7％,产胶率 87.6％,各种性能基本保持不变。      

黄原胶菌种的诱变育种及优化培养

对黄原胶菌种进行紫外线诱变和原生质体诱变处理后，紫外线诱变菌株的产胶量与诱变前无明显提高，而原生质体诱变株的产胶量较原菌株有一定提高，提高最大的为21％。还对黄原胶菌种的培养条件进行了研究，得到最佳培养基配方为：玉米淀粉3．0％，葡萄糖1．0％，蛋白胨0．4％，酵母膏O，2％，碳酸钙0．2％，磷酸氢二钾0．1％，硫酸镁0．05％，pH值7．0。其发酵液粘度可达9800cp。此外，对其他培养条件也做了试验分析。     

介绍一种简便的菌种保藏方法

介绍一种简便的菌种保藏方法江西海泉生物工程公司（336000）钟启平随着饲料工业的发展，固态发酵技术在活性酵母饲料和其它一些饲料产品的生产中得到了迅速的推广和发展，菌种退化则是一些介业经常发生的事。这里介绍一种菌种维护与保藏方法，经多年的实践，证明它非常简...     

一种简单长期保藏乳酸菌菌种方法的研究

为了适应发酵蔬菜生产企业菌种保藏,本试验探讨乳酸菌培养基质的灭菌时间,并在单因素试验基础上,采用响应面法优化改良MRS培养基配方。结果表明,乳酸菌培养基质白菜帮颗粒灭菌时间为9 min,改良MRS培养基最佳配方为：白菜帮颗粒25 g/L、蛋白胨9 g/L、牛肉膏8 g/L、葡萄糖14 g/L、柠檬酸三铵2 g/L、酵母膏5 g/L、乙酸钠2 g/L、K2HPO4 2 g/L、MgSO4·7H2O 0.58 g/L、MnSO4·4H2O 0.25 g/L。在优化培养基条件下,副干酪乳杆菌的菌数为1.19×1010 CFU/mL。1～4 ℃冷藏可保藏3～4年,-16～-20 ℃冷冻可保藏4～5年。此保藏方法操作简单、成本低,菌种质量稳定可靠,适合蔬菜发酵企业保藏生产用乳酸菌菌种。     

葡萄酒酿酒菌种的保藏方法

本文介绍了酿酒菌种常用的保藏方法,酵母菌的短期保藏可采用橡皮塞代替棉塞的斜面试管或液体试管保藏法,长期保藏可采用液体石蜡保藏法,乳酸菌的短期保藏可用液体试管和穿刺培养保藏法,长期保藏可用旋塞试管保藏法,但长期有效的保藏菌种还是以真空冷冻干燥保藏法最行。     

食品检验中的菌种保藏方法

综述了食品检验中常用的菌种保藏方法,包括定期移植保藏法、液体石蜡保藏法、载体保藏法、低温保藏法和冷冻干燥保藏法,旨在为食源性致病菌菌种的保藏提供参考。     

浅谈微生物菌种保藏方法

简要介绍常用微生物菌种的保藏方法及优缺点比较,同时结合多年微生物检验工作经验,以期为微生物菌种的保藏提供参考.     

无菌蒸馏水长期保藏酵母菌种的研究

采用蒸馏水长期保藏酵母菌种进行了3年的研究。结果表明，经蒸馏水保藏3年的酵母菌种其发酵特性无明显改变。证明该方法是一种长期保藏酵母菌种行之有效的的方法。     

A simple and effective method for detecting toxicity of chromium trioxide on Vicia faba

In modern biological research, there are many analytical methods to evaluate the toxicity caused by chemical agents, such as higher plant bioassay, flow cytometry, single-cell gel electrophoresis or the comet assay. However, these methods are either tediously experimental procedures or require a high-tech platform. In this study, the effects of chromium trioxide (CrO₃) on the primary root growth of Vicia faba seeds over 72 h were investigated. The primary root length of seeds cultivated in different concentrations of CrO₃ was collected and analyzed. It was indicated that the Vicia faba seeds maintained a good growing state when the CrO₃ concentration was below 100 μmol/L, while the root growth was suppressed when they were kept in 250 μmol/L of CrO₃ for 72 h or cultured with CrO₃ concentrations above 500 μmol/L. In comparison with the chromosome aberration bioassay, the primary root length assay is proved in this paper to be a simple and effective alternative for water toxicity testing in areas where heavy metal pollution has become serious.     

A simple and effective method using macroporous resins for the simultaneous decoloration and deproteinisation of Cordyceps militaris polysaccharides

The aim of this study was to develop an effective one-step decoloration and deproteinisation method using macroporous resin for Cordyceps militaris polysaccharide (CMP) extraction. Performances of different resins were compared, and the structures and bioactivities of CMP recovered using this one-step method were evaluated and compared with traditional methods. The results showed that NKA-9 resin exhibited the highest adsorption capacity for pigment and free protein than other tested resins. Under the optimised condition, NKA-9 resin adsorption exhibited high decoloration ratio (80.69%), deproteinisation ratio (62.51%) and polysaccharide recovery ratio (78.08%). Furthermore spectroscopic analysis revealed that the structure of CMP remained unchanged after adsorption, but some reagent residues can be detected using traditional methods. Compared with traditional methods, the antioxidant activity of CMP extracted using a one-step method was significantly higher, without negative impact on cell viability. Thus, this novel technique is a promising alternative method for CMP separation and purification.     

A simple urine-collecting apparatus and method for cows and heifers

An apparatus and method that can allow continuous and precise total collection of urine under normal conditions was developed that could satisfy the urine-sampling requirement of balance studies, metabolic experiments, and hormone trials of cows and heifers. The apparatus is composed of an anterior urethra, a urine cup, and a collection barrel. Total and precise collection of urine can be achieved without leakage, fecal contamination, or urethra infection. The apparatus has few negative effects on the cows and does not influence the cows’ normal physiological activities.     

还原型谷胱甘肽简便测定法

对测定还原型谷胱甘肽-四氧嘧啶305法的改进。适合于GSH浓度介于0.02￣0.10mg/mL的样品分析,回归方程为:y=5.77x,R2=0.9970,最大误差不超过4%。该法可用于发酵液中GSH的直接测定,结果满意。     

介绍一种简便长期保藏醋酸菌的方法

介绍了一种简便实用的醋酸菌保藏方法:制备20%甘油的醋酸菌悬液,4℃平衡24h后,于-20℃或-80℃条件下保存,此方法可至少有效保存醋酸菌2年。     

A simple and rapid turbidimetric method for determining catechins in beverages

We have developed a simple and rapid turbidimetric method to determine catechins based on the fact that many polyphenols produce hydrogen peroxide in an alkaline environment and that hydrogen peroxide oxidises cerium to generate cerium oxide precipitates. Four catechins (epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate) aggregated with these precipitates to form massive precipitates with increased turbidity. The catechins solution (0.18 mL) was mixed with 0.02 mL of 1% CeCl₃ solution, and absorbance (650 nm) was measured immediately after agitation for 3 min using a spectrophotometer. Absorbance was strongly correlated (0.99) with the concentration of each catechin compound. For commercially bottled green tea, the estimated catechin content determined using this turbidimetric method showed better correlation with the content determined by high‐performance liquid chromatography than that determined using ferrous tartrate method, which is the official Japanese method for determining the tannin content of green tea.     

A simple and rapid colorimetric method for lactose determination in milk

A simple and rapid technique for the estimation of lactose in fluid milk and whey, utilizing trichloroacetic acid (TCA) as a precipitating agent, is outlined. The color development is based on the reaction of picric acid with lactose in the presence of phenol, sodium hydroxide and sodium bisulfate. This method can be completed within 10 min. There is no significant difference (p ≤ 0·05) between the results obtained by the proposed method and those obtained by the IDF method.