卡泊芬净合成前体Pneumocandin B0的发酵工艺研究

以Pneumocandin B0 PB5—31为出发菌株,从筛选高产菌株和提高产物中有效组分的比例两方面进行研究,以期提高Pneumocandin B0的发酵水平。结果表明,紫外线诱变复合氯化锂后处理筛选出高产菌株,其发酵效价比出发菌株提高了72％;发酵培养基中添加0．3％的脯氨酸很好地提高了有效组分B0的比例。     

卡泊芬净合成前体Pneumocandin Bo的发酵工艺研究

以Pneumocandin B0 PB5-31为出发菌株,从筛选高产菌株和提高产物中有效组分的比例两方面进行研究,以期提高Pneumocandin B0 的发酵水平.结果表明,紫外线诱变复合氯化锂后处理筛选出高产菌株,其发酵效价比出发菌株提高了72％;发酵培养基中添加0.3％的脯氨酸很好地提高了有效组分B0的比例.     

卡泊芬净合成前体Pneumocandin Bo的发酵工艺研究

以Pneumocandin B0 PB5-31为出发菌株,从筛选高产菌株和提高产物中有效组分的比例两方面进行研究,以期提高Pneumocandin B0 的发酵水平.结果表明,紫外线诱变复合氯化锂后处理筛选出高产菌株,其发酵效价比出发菌株提高了72％；发酵培养基中添加0.3％的脯氨酸很好地提高了有效组分B0的比例.     

抗药性基因突变筛选高产菌株

本文通过洁霉素对盐酸林可霉素产生菌 98-1菌株孢子的致死浓度测定 ,采用诱变剂EMS的四种不同诱变剂量对菌株孢子进行诱变处理 ,诱变处理的孢子涂布在含洁霉素 ( 2 0 0 0 0ug/ml)的高氏平板上 ,获得了大量的洁霉素抗性基因突变株 ,然后从 90 0株洁霉素抗性基因突变株中通过初筛获得高于诱变出发菌株产素能力的菌株 5 6株 ,再进一步通过摇瓶复筛 ,并结合菌丝生长及摇瓶代谢情况 ,获得优于出发菌株的诱变菌株 4株。将这 4个菌株连同出发菌株连续三批次进行摇瓶发酵 ,结果 4个突变株的产素能力 (产量 )及摇瓶代谢和菌丝生长情况均优于出发菌株 ,试验筛选出最优菌株 0 2 -0 3 -40 2。将 0 2 -0 3 -40 2进行罐上发酵生产试验 ,结果试验罐比对照罐平均效价提高 1 7.5 6% ,平均产量提高 1 9.3 4%。本文建立了林可霉素高产菌株的洁霉素抗性基因突变诱变快速高效的筛选方法     

利福霉素SV高产菌株0124-8~#的选育

以现有生产菌株11#为出发菌株,进行硫酸链霉素抗性诱变。采用梯度平板及琼脂块法筛选,得到0124-8#菌株。试验结果表明,其发酵单位大幅度提高,较出发菌株提高了8.9%,并且其遗传稳定性较好。     

井冈霉素高产菌种的选育

井冈霉素是一种在井冈山地区发现的微生物菌株所产生的农用抗生素 ,对水稻纹枯病有显著的防治效果 ,药效达 90 %以上。虽然从井冈霉素发现迄今已有 30年 ,但由于其具有高效、低毒 ,对环境安全 ,以及尚未发现抗药性 ,因而该产品仍拥有一个稳定的市场。但是多年以来井冈霉素的发酵生产水平一直徘徊在 1 0 0 0 0～ 1 2 0 0 0r/mL(以A组份计 ,下同 ) ,我们以本公司的井冈生产菌种为出发菌种 ,用紫外线进行诱变处理 ,筛选出了发酵效价稳定的高产菌株UV 1 99,摇瓶发酵效价可达到 2 0 0 1 5r/mL(补足摇瓶蒸发水份后测得 ) ,比出发菌株 1 4 1 5 8r…     

农用抗生素产生菌Streptomyce SN03菌株的诱变选育

以链霉菌SN03菌株为出发菌株,采用紫外线诱变结合微波诱变的处理方法,通过对致死率、正负突变率和活性最大提高率的测定,确定了紫外线和微波诱变的最适时间,结合对诱变菌株的传代稳定性测定,获得了高效菌株UV-1-W3,其发酵液的抑菌圈直径达到33.2mm,抗菌活性比出发菌株提高了30.20%。     

替考拉宁高产菌株的选育

以替考拉宁产生菌1-16为出发菌株,经热诱变复合替考拉宁抗性筛选高产菌株,获得一株高产突变菌株TC3-25,其替考拉宁产量较出发菌株提高46%。传代试验表明该菌株的发酵水平较稳定。     

利用组合抗药性突变选育秦岭霉素高产菌株

以秦岭链霉菌为出发菌株,采用链霉素和庆大霉素对其进行抗药性诱变.通过对致死率和活性最大提高率的测定,确定了链霉素和庆大霉素对出发菌株的最小抑制质量浓度(MIC),并在最小抑制质量浓度下筛选抗药性突变菌株.结合对诱变菌株的传代稳定性测定,获得了3株抗药性突变的高产菌株GS-4-04、GS-4-05和GS-4-06,其发酵液对5种细菌和4种病原真菌的抗菌活性比原始菌株显著提高.     

沼泽红假单胞菌在低温下对水中总氮的降解

本文采用亚硝酸盐诱变与温度驯化处理的复合诱变方法,对能够高效降解水中总氮的沼泽红假单胞菌出发菌株进行诱变处理,选育出能一株在低温条件下生长良好、性状稳定,且能够在低温条件下高效降解水中总氮的沼泽红假单胞菌驯化菌株。与出发菌株相比,驯化菌株在15℃时的生长以及总氮降解率均好于出发菌株,其对总氮降解率可达到69.08%,比出发菌株提高了43.49%。     

分解炉扩径的技术改造

我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

A study of miscibility of blends of polybutadienes of varying microstructure

The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure.     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

粉煤灰中烧失量检测的不确定度分析

以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。     

生物油的成分分析及物性测定

以添加FeCl2的ZnCl2-KCl混合熔盐裂解纤维素和秸秆,制得生物油。采用傅立叶变换红外光谱法和气相色谱-质谱法分析生物油的成分。结果表明,生物油中成分复杂,含有氧元素、多种有机化合物,主要包括酮类、醛类、酚类及羧酸类等。测定了20～80℃生物油的密度和粘度,发现生物油的密度与温度呈较好线性关系,而生物油的粘度均大于水的粘度,且不同熔盐体系对秸秆生物油的粘度无较大影响。     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003