Effect of propionate on the production of natamycin with Streptomyces gilvosporeus XM-172

This study described the influence of feeding short-chain fatty acids and alcohols on natamycin production in the glucose basal medium, produced by Streptomyces gilvosporeus XM-172. The highest natamycin production was obtained with feeding propionate as compared to other precursors. The optimal propionate concentration and feeding time were 6 g L(-1) and early log phase, respectively. This optimal propionate feeding strategy led to a natamycin production of 6.72 g L(-1), which was nearly 85% higher than that of the control. It was firstly revealed that propionate could greatly promote natamycin biosynthesis by S. gilvosporeus

Medium optimization for Schizochytrium sp. to produce docosahexaenoic acid (DHA)

以筛选得到的Schizochytrium sp.菌株作为研究对象,考察了培养基碳源、氮源对该菌株生物量的影响,通过响应面法建立了菌体生物量与葡萄糖、酵母粉以及玉米浆浓度之间的关系,得到较佳培养基组成为:126g/L葡萄糖、10g/L酵母膏、2g/L玉米浆、5g/L蛋白胨、0.5倍浓度自然海水1L。摇瓶发酵结果表明:在5d培养时间,Schizochytriumsp.生物量、积累油脂以及DHA分别可达42.9、34.1、13.8g/L。One strain of Schizochytrium sp.was selected as the mode microorganism to evaluate the influences of carbon and nitrogen resource on the biomass.By employing response surface method,the relationship between biomass and nutrients was founded and the optimized culture medium for Schizochytrium sp.was determined.The optimized medium consisted of 126 g/L glucose,10 g/L yeast extract,2 g/L corn steep liquor,5 g/L soy peptone and half the salt concentration of seawater 1 L.The maximum biomass,total fatty acid and DHA reached 42.9 g/L,34.1 g/L and 13.8 g/L on the optimized culture medium after 5 days incubation,respectively

Effects of Indoor and Outdoor Cultivation Conditions on the Cell Growth and Lutein Accumulation of Thermo-tolerant Desmodesmus sp.F51

在室内培养耐温微藻F51,考察了培养温度、自来水及非灭菌培养基对细胞生长及叶黄素积累的影响,并与50 L柱状光生物反应器户外分批培养情况进行对比.结果表明,藻株在35℃下的生物质产率和叶黄素产率最大,分别为767.5和3.05mg/(L·d).低温培养有利于叶黄素积累,但生长速率减缓.用自来水及非灭菌培养基培养时,藻株无明显的生长抑制及染菌现象,在13.0~27.6℃户外培养温度下,藻株最高生物质产率、二氧化碳固定率和叶黄素产率分别为236.3,444.2和1.17 mg/(L·d).The effects of temperature, local tap-water and culture medium without sterilization on cell growth and lutein production of Desmodesmus sp. F51 were investigated under indoor conditions. Outdoor batch cultivation of Desmodesmus sp. F51 was also investigated in 50 L cylindrical photobioreactor. The results showed that the best biomass productivity [767.5 mg/(L·d)] and lutein productivity [3.05 mg/(L·d)] occurred at a temperature of 35 ℃. A low temperature enhanced the lutein content but reduced cell growth rate. There is no significant growth inhibition and microbiological contamination were observed for Desmodesmus sp. F51 using local tap-water and culture medium without sterilization. Under the outdoor temperature of 13.0~27.6 ℃, the highest biomass productivity, CO2 fixation rate and lutein productivity of 236.3, 444.2 and 1.17 mg/(L·d) were obtained, respectively,.福建省青年科技人才创新基金资助项目(编号:2016J05077);; 福建省教育厅资助项目(编号:JA15077

Production of β-glucanase by Biosynthesis Method

概述了微生物来源的β-葡聚糖酶国内外生产现状,介绍了生产β-葡聚糖酶的不同方法,对生物合成法及其产酶的影响因素进行了具体分析,并指出今后中国β-葡聚糖酶的研究方向。Present research situation and strategies of production of β-glucanase from micro-organism were reviewed.Factors influencing β-glucanase production by biosynthesis method were analysed specifically,and what should be researched in β-glucanase in our country was pointed out.广东省科技计划项目资

High regioselective acetylation of vitamin A precursors using lipase B from Candida antarctica in organic media

The effect of different reaction parameters was explored on the acylation of primary hydroxyl group of 1,6-diol by lipase B from Candida antarctica catalysis in organic solvent. First, the effect of the organic solvents was investigated, and the highest conversion rate was obtained in n-hexane. Then, the effect of the acyl donor was studied. Among several reactants, including acetic acid and two different acetates, vinyl acetate gave the best yield. A maximum monoester yield of 98.5% was obtained using vinyl acetate as acyl donor in n-hexane at 50 degrees C. The substrate concentration was 25 mmol/L, while the diol to vinyl acetate molar ratio was 1:3. Substrate concentration had to be limited due to an inhibitory effect on enzyme by the diol that caused a decrease on initial reaction rate. To promote initial reaction rate, excess vinyl acetate was used. Under the optimum conditions, the conversion rate and monoacylation selectivity were 98.5 and 100%, respectively. The produced monoester was 6.1 mg/ml, and this amount can be further optimized base on the results presented here

Thermodynamics and kinetics of D-glyceric acid adsorption on ion exchange resin

D-甘油酸是一种重要的甘油衍生物,具有解酒护肝的功能。关于D-甘油酸生产方法的研究已有不少,但对其分离方法及分离机理的研究却鲜见报道。通过静态吸附实验,研究了D-甘油酸在201×7阴离子交换树脂上的等温热力学和动力学特性。结果表明,D-甘油酸在201×7阴离子交换树脂上的最大平衡吸附容量随p H的增加而降低,其吸附等温线符合Freundlich模型。在293~308 K下,吸附焓变为14.77 k J·mol-1,表明该吸附过程为吸热过程。升高温度有利于提高吸附速率,但对最大平衡吸附容量影响不大。同时,采用动边界模型描述D-甘油酸在该树脂上的交换行为,分别考察了料液浓度、树脂粒径和温度对交换过程的影响。交换过程的吸附速率随D-甘油酸浓度和温度的增加而增大,但随树脂粒径的增大而减小。研究表明该离子交换过程的速率控制步骤为颗粒扩散过程,交换过程的反应速率常数k0为1.22×10-3,反应级数a为0.631,表观活化能Ea为14.90 k J·mol-1,并得到了动力学总方程。D-glyceric acid, one of the promising glycerol derivatives, has various biological functions such as accelerating ethanol and acetaldehyde oxidation. Plenty studies on the synthesis but few studies on downstream processes to recover D-glyceric acid were available. A static equilibrium adsorption was performed to study isothermal thermodynamics and kinetics of D-glyceric acid adsorption onto 201×7 strong basic anion exchange resin. The results showed that the adsorption process followed the Freundlich isothermal model at different p H and temperature conditions, which the maximum adsorption capacity decreased with increasing initial p H. The change of adsorption enthalpy was 14.77 k J·mol-1 at 293—308 K, suggesting an endo-thermic adsorption process. Raising temperature improved adsorption rate with limited influence on equilibrium adsorption capacity. The Dynamic Boundary Model was used to investigate adsorption kinetics with a focus on effects of D-glyceric acid concentration, resin particle diameter and adsorption temperature. The results suggested the particle diffusion was rate-limiting step of the adsorption process. The adsorption rate increased with the increase of D-glyceric acid concentration and temperature, but decreased with the increase of resin particle diameter. The general kinetics equation was obtained with the rate constant of exchange(k0), reaction order(a) and the apparent activation energy of reaction(Ea) as following k0=1.22×10-3, a=0.631, Ea=14.90 k J·mol-1.福建省高校产学合作项目(2015N5006);; 福建省教育厅中青年教师教育科研项目(JA15393);; 泉州师范学院青年博士预研基金项目(2015QBKJ04)~

Applications of Chlorella in food industry

现代食品工业正朝着绿色健康、便利的方向发展,具有保健功能的天然产物将是今后新型食品的一个重要发展方向。小球藻因高蛋白、富含类胡萝卜素、维生素等特; 点,具有多种保健功能,可作为功能性食品或保健品应用于食品行业中。本文综述了近年来小球藻在保健食品、功能性食品中的研究和应用进展,着重介绍了小球藻; 在保健食品及主食、副食、饮料等功能性食品中的具体应用和国内外研究进展,以期为今后小球藻在食品行业中的应用提供参考。Modern food industry aimed at green,healthy and more convenient foods.; The use of natural ingredients with functional activity was an; attractive way to design new foods.Due to its high in protein content; and richness in carotenoids and vitamins,Chlorella had many healthcare; functions and could be used in food industry as a functional food and; nutrition enhancing agent.Research progress in the applications of; Chlorella in health food and functional foods in recent years,especially; in staple food,baked food,and beverage,was reviewed in this paper in; order to provide valuable information for the further application of; Chlorella in food industry.国家自然科学基金; 福建省高校产学合作项目; 福建省教育厅中青年教师教育科研项目; 泉州市科技局校地协同创新项

Immobilized cultivation of Dictyostelium discoideum with polyurethane foam

研究了聚氨酯泡沫应用于固定化盘基网柄菌的可行性,发现以简单处理过的聚氨酯泡沫为载体,能够高效实现盘基网柄菌的固定化培养。考察了载体粒径大小、载体量和摇床转速等对固定化培养的影响,在优化的培养条件和固定化条件下,盘基网柄菌的最大细胞密度是悬浮培养的2~4倍。The immobilization of D.discoideum with polyurethane foam(PUF) was proposed and the effects of PUF's properties on the immobilization was examined.The results showed that PUF was a suitable carrier for the efficient imoblization of D.discoideum.The effects of PUF addition and culture conditions were optimized to attain high density of D.discoideum.Under optimized culture conditions,high cell density of D.discoideum(4.56×107 cells/mL) has been achieved in the shake flasks,which was 2～4 times higher than that of free-cell culture in the axenic medium.国家自然科学基金资助项目(30370039

Arachidonic acid oil production by microbial fermentation

花生四烯酸(ArA)是一种重要的脂肪酸,现在主要由生物法生产,本文综述了高山被孢霉发酵生产花生四烯酸油脂的菌落形态控制及其代谢途径,以期为相关的研究者提供参考。Arachidonic acid(ARA) is a very important fatty acid,and mainly proudced by biological method.In this paper,production of ARA by Mortierella alpina and the involved metabolic pathways were reviewed,in order to provide references for relative research.广东省工业技术研究院生物工程研究所科技基金(B201301