Optimization of culture conditions and scale-up to pilot and plant scales for vancomycin production by <Emphasis Type="Italic">Amycolatopsis orientalis</Emphasis>

This report describes the optimization of culture conditions for vancomycin production by Amycolatopsis orientalis KCCM-10836P, an identified high-vancomycin-producing strain (US11/712,494). Among the conditions tested, pH and the dissolved oxygen tension (DOT) were key factors affecting vancomycin production. When the pH and DOT were controlled at 7.0 and 20–30%, respectively, a dry-cell weight (DCW) of 62.0 g l⁻¹ and a vancomycin production of 11.5 g l⁻¹ were obtained after 120 h of batch culture, corresponding to a specific vancomycin content of 185.4 mg g-DCW⁻¹. Vancomycin production was scaled up from a laboratory scale (7-l fermentor) to a pilot scale (300 l) and a plant scale (5,000 l) using the impeller tip velocity (V _tip) as a scale-up parameter. Vancomycin production at the laboratory scale was similar to those at the pilot and plant scales.     

Optimization for high-density cultivation of heterotrophic Chlorella based on a hybrid neural network model

AIMS: The purpose of this study was to develop a reliable hybrid neural network (HNN) model for heterotrophic growth of Chlorella, based on which optimization for fed-batch (FB) cultivation of Chlorella may be successfully realized. METHODS AND RESULTS: Deterministic kinetic model was preliminarily developed for the optimization of FB cultivation of Chlorella. The highest biomass concentration and the maximum productivity were obtained as: 104.9 g l(-1) dry cell weight and 0.613 g l(-1) h(-1), respectively. After several cultivations had been performed, an HNN model was developed. The efficiency of biomass production was further increased by the optimization using this model. The highest biomass concentration and the maximum productivity attained was: 116.2 g l(-1) dry cell weight and 1.020 g l(-1) h(-1), respectively. CONCLUSION: The HNN model agreed well with experimental results in different cultivations. Comparison between the HNN model and the deterministic model showed that the former had better generalization ability, which made it a reliable tool in modelling and optimization. SIGNIFICANCE AND IMPACT OF THE STUDY: The high cell density and productivity of biomass obtained in this study is of significance for the commercial cultivation of Chlorella. The simple and efficient optimization strategy proposed in this paper may be employed in heterotrophic mass culture of Chlorella as well as other similar organisms.     

Nitrate removal with bacterial cells attached to quartz sand and zeolite from salty wastewaters

A mixed bacterial culture was acclimated to the removal of high nitrate-N concentrations (100–750 mg NO₃ ⁻-N L⁻¹) from salty wastewaters. The experiments were carried out under anoxic conditions in the presence of 0.5, 1.5 and 3% (w/v) NaCl at different temperatures. The acclimated mixed bacterial culture was attached to quartz sand and zeolite. Denitrification was monitored in a continuous-flow bioreactor at different hydraulic retention times (HRT). Nitrate removal with cells attached to quartz sand and zeolite was completed at HRT of 167 h and 25 h respectively. Then brine denitrification with bacterial cells attached to zeolite was monitored for 85 days. Under the increased nitrate loading rate, nitrate removal was above 90%. Furthermore, during denitrification, not more than 0.5 mg NO₂ ⁻-N L⁻¹ could be produced. It can be concluded that nitrate removal with the cells attached to zeolite is economically and operationally a promising solution to denitrification of brine wastewaters.     

脂肪酶产生菌Aspergillus sp.FS132产酶条件的初步优化及其18S rRNA基因序列的比较分析

从新疆火焰山口土样中分离的一株脂肪酶产生菌FS132,菌落形态表明为霉菌。对其产酶条件的初步优化表明,产酶的最适培养时间为45h,培养基最适初始pH7．0,最适培养温度36℃,最适摇瓶空气量25mL／250mL锥形瓶。为进一步鉴定该菌株,克隆测定了该菌18SrRNA基因序列。并对其进行系统进化树分析,结果表明该菌与已报道的Aspergillus tamarii具有最紧密亲缘关系。     

Plasmid system for the intracellular production and purification of affinity-tagged proteins in Bacillus megaterium

A multiple vector system for the intracellular high-level production of affinity tagged recombinant proteins in Bacillus megaterium was developed. The N- and C-terminal fusion of a protein of interest to a Strep II and a His(6)-tag is possible. Corresponding genes are expressed under the control of a xylose-inducible promoter in a xylose isomerase deficient host strain. The exemplatory protein production of green fluorescent protein (GFP) showed differences in produced and recovered protein amounts in dependence of the employed affinity tag and its N- or C-terminal location. Up to 9 mg GFP per liter shake flask culture were purified using one-step affinity chromatography. Integration of a protease cleavage site into the recombinant fusion protein allowed tag removal via tobacco etch virus (TEV) protease or Factor Xa treatment and a second affinity chromatographic step. Up to 274 mg/L culture were produced at 52 g CDW/L using a glucose limited fedbatch cultivation. GFP production and viability of the production host were followed by flow cytometry.     

Application of cellulases from an alkalothermophilic Thermomonospora sp. in biopolishing of denims

Use of cellulase for denim washing is a standard eco-friendly technique to achieve desirable appearance and softness for cotton fabrics and denims. But enzymatic washing of denim till date involved acid cellulase (Trichoderma reesei) and neutral cellulase (Humicola isolens) the use of which has a drawback of backstaining of the indigo dye on to the fabric. Though it has been suggested that pH is a major factor in controlling backstaining there are no reports on use of cellulase under alkaline conditions for denim washing. In this study for the first time an alkali stable endoglucanase from alkalothermophilic Thermomonospora sp. (T-EG) has been used for denim biofinishing under alkaline conditions. T-EG is effective in removing hairiness with negligible weight loss and imparting softness to the fabric. Higher abrasive activity with lower backstaining was a preferred property for denim biofinishing exhibited by T-EG. The activities were comparable to acid and neutral cellulases that are being regularly used. The enzyme was also effective under non-buffering conditions which is an added advantage for use in textile industry. A probable mechanism of enzymatic finishing of cotton fabric has been represented based on the unique properties of T-EG.     

培养基对透明颤菌生长的影响

目的:为了从环境中分离透明颤菌(Vitreoscilla),对培养基和生长条件进行了优化。方法:采用富集培养的方法,对透明颤菌生长的培养基成份进行了筛选试验。结果:在培养温度为32±2℃,50ml/500ml三角瓶,pH 7.8,醋酸钠浓度为0.02%,摇床转速120r/min条件下,透明颤菌生长最佳培养基是:酵母粉0.7%,蛋白胨0.3%。结论:透明颤菌在上述培养基中生长12h可达到高峰。     

珍稀植物毛花轴榈的开发利用

为了有效地保护和利用我国的珍稀野生植物资源,对珍稀濒危植物毛花轴榈的形态特征、分布、繁殖栽培及适应性进行了介绍,并对其在园林上的应用进行了探讨.认为毛花轴榈是优良的庭园绿化和室内观赏植物,值得推广应用.     

燃油植物香叶树的开发利用与栽培

我国木本油脂植物种类很多,特别是在我国亚热带地区分布很广,但分布零散.香叶树在云南腾冲县有比较集中的资源,其果实含油率很高,是加工生物柴油的良好原料.分析了香叶树油用于生物柴油的有利条件,并介绍了香叶树栽培技术要点,供有条件的地区发展香叶树资源与生产时参考.     

peD—awte候选疟疾DNA疫苗发酵条件的探索

探索pcD—awte候选疟疾DNA疫苗发酵条件,为该疫苗制备工艺的建立做准备。通过摇瓶和5L发酵罐水平,考察不同培养基组成及来源、补料变化和温度转换对工程菌生长及质粒产量的影响。结果表明在TB培养基组分中添加Mg^2＋、微量元素复合物、核苷等成分,补料培养基由葡萄糖代替甘油,对数中期温度由37％升至42℃等条件,能提高工程菌株pcD—awte质粒的产量。在优化的培养条件下pcD—awte质粒产量可达125—130mg／L培养液。