竹黄菌液体培养下产竹红菌素的研究

先对不同产地采集的竹黄菌进行筛选,得到优产竹红菌素的菌株,然后采用单因子和3因素3水平正交试验法对竹红菌素液体发酵条件进行优化,在优化培养基的基础上,选用不同浓度的Cr3+、Fe3+、Cu2+和Ca2+对竹红菌素进行离子调控研究。结果表明:从休宁所采集的菌株不仅生长速度最快,发酵所产的竹红菌素含量也最高;竹红菌素最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠,最佳培养基组合为2%葡萄糖,0.2%硝酸钠,pH7.5;Cr3+和Fe3+浓度为0.005%时竹红菌素含量均最高;0.05%的Ca2+最有利于竹红菌素的分泌;Cu2+为0.03%时竹红菌素含量达到最大值。     

Study on fermentation hypocrellin by Shiraia bambusicola in submerged cultures

先对不同产地采集的竹黄菌进行筛选,得到优产竹红菌素的菌株,然后采用单因子和3因素3水平正交试验法对竹红菌素液体发酵条件进行优化,在优化培养基的基础上,选用不同浓度的Cr3+、Fe3+、Cu2+和Ca2+对竹红菌素进行离子调控研究.结果表明:从休宁所采集的菌株不仅生长速度最快,发酵所产的竹红菌素含量也最高;竹红菌素最佳发酵碳源是葡萄糖,最佳发酵氮源是硝酸钠,最佳培养基组合为2%葡萄糖,0.2%硝酸钠,pH7.5;Cr3+和Fe3+浓度为0.005%时竹红菌素含量均最高;0.05%的Ca2+最有利于竹红菌素的分泌;Cu2+为0.03%时竹红菌素含量达到最大值.     

安徽省三种产地竹黄菌培养的初步研究

首次对安徽省三种产地的竹黄菌进行了组织分离培养和液体发酵,比较了该菌固体生长状况和液体发酵形成的竹红菌素产量。结果显示,广德卢村的菌种平皿生长速度为0．31cm／d,液体发酵产生的竹红菌素吸光度为0．21;宁国板桥菌种平皿生长速度为0．30cm／d,液体发酵产生的竹红菌素吸光度为0．30;休宁武城的竹黄菌平皿生长速度为1．85cm／d,菌株液体发酵产生的竹红菌素吸光度为O．39。结论表明,休宁武城菌种无论是平皿生长速度还是发酵形成的竹红菌素量都明显优于其它两地的菌株。     

耐有机溶剂蛋白酶产生菌Bacillus cereusWQ9—2发酵条件及酶学性质

以蜡状芽孢杆菌Bacillus cereus WQ9—2为产耐有机溶剂蛋白酶的出发菌株,对其产酶条件进行优化并初步研究了其酶学性质。在单因素实验基础上,通过中心复合实验确定了产酶的最佳发酵条件为酵母粉8g/L,葡萄糖17g/L,KH2P040．5g／L,无水MgS040．3g／L,CaCl20．5g／L,NaCl1．0g/L;pH7．5。实验中发现采用低温发酵能大大缩短菌体产酶周期;通过优化发酵时间由最初84h缩短到48h,最高比酶活为3921U／mL。金属离子螯合剂1,10菲罗啉（1,10-phenanthroline）、乙二胺四乙酸（EDTA）对该酶有较强的抑制作用,表明该酶可能为金属蛋白酶;Ca2＋对该酶的活力及热稳定性有显著提高作用。     

产黄酮银杏内共生真菌的分离及其发酵条件的优化

本文从不同年龄、不同地域的银杏叶、茎、根部组织中分离得到20株银杏内共生真菌,经过发酵复筛有5株的产黄酮能力超过5μg/m L。实验对菌株的最佳发酵产黄酮条件进行了优化,优化条件为:3%葡萄糖、0.5%蛋白胨、0.4%酵母膏、0.3%KH2PO4、0.01%Mg SO4·7H2O;起始p H值7.0、最适发酵温度28℃、摇床转速为140 r/min、装液量125 m L/250 m L。在此条件下,该系列菌株在发酵7 d左右产黄酮量可达6.4μg/m L。     

竹黄菌发酵生产竹红菌素的研究进展

竹黄作为名贵中药,其主要成分竹红菌素是优良的天然光敏药物。由于天然竹黄资源有限,通过竹黄无性型菌株发酵生产竹红菌素因而受到广泛关注。通过介绍竹黄无性型菌株的固态、液态发酵,分析了竹红菌素发酵生产的各种影响因子,并对竹红菌素合成诱导物质及高产菌株诱变筛选等进行了综述,为竹红菌素合成调控和发酵生产提供了参考。     

竹黄菌固态发酵竹红菌素条件的研究

研究了竹黄菌固体发酵培养生成竹红菌素过程中培养条件的影响。结果表明,竹黄菌生长及竹红菌素生成适宜的温度、pH分别为26℃、5．5—6。最佳的培养基物料厚度为5cm左右。固态发酵过程中最适的水份含量为50％。玉米粉是一种适宜的培养基基本组成。在以上发酵条件下竹红菌素产量为4mg/kg。     

酵母菌产麦角固醇发酵条件的研究

为了提高酵母菌麦角固醇的产量,采用摇瓶培养法,对筛选出的一株酵母菌YN2产麦角固醇发酵条件进行了研究。结果表明,酵母菌YN2产麦角固醇适宜的培养基配方为：酵母粉1％,牛肉膏2．5％,葡萄糖8％,K2HPO4 0．3％,MgSO4 0．15％,该菌株产麦角固醇最适培养条件为：培养温度28℃,起始pH6．5,发酵时间72h。在优化的实验条件下,麦角固醇含量可达2．2％,100ml发酵液中麦角固醇产量达25．30mg。     

5′—磷酸二酯酶高产菌株的选育和发酵培养条件的优点

以ATCC14994为出发菌株,采用紫外线与亚硝基胍相结合的多次诱变育种,获得1株5′-磷酸二酯酶高产菌株HAT2228.通过单因子和正交试验对该菌株的产酶发酵条件进行了优化,优化发酵产酶条件为蔗糖5%,酵母膏0 3%,蛋白胨0.3%,K2HPO4 0.8%,KH2PO40.8%,MgSO4 0.2%,ZnSO4 0.2%,培养基起始pH6 0,接种量10%,培养温度30℃,摇床转速120r/min,发酵时间48h.在优化条件下,HAT2228的产酶水平达1 329u/ml.     

Caldariomyces fumago S-5产抑菌物质的发酵条件优化

对1株产抑菌物质的海洋真菌Caldariomyces fumago S-5的培养条件的优化进行研究,探讨该菌株的发酵产抑菌物质的性能。通过抗菌谱实验、单因素及正交实验设计研究了该菌株所产抗菌物质的押菌特征和最适发酵条件。结果表明,S-5菌株发酵液对几种G^＋和G^-致病细菌具有快速的生长抑制作用,而对真菌没有明显抗菌性。发酵条件优化结果表明：菌株在葡萄糖4％、（NH4）2SO4 0．2％、KCl 0．2％、K2HPO40．2％、Fe2SO4·7H2O 0．002％、MgSO4-2H2O 0．1％、20％马铃薯浸出液的培养基中,控制发酵温度25℃,pH值5．0,接种量1-2cm。菌苔／100mL培养液,摇瓶转速240r／min条件下培养120h,发酵液中抑菌效价最高。实验结果可为该海洋微生物资源的开发利用提供依据。     

产γ-谷氨基甲酰胺合成酶菌株的筛选及产酶条件研究

以假单胞菌(Pseudomonas sp.)为出发菌株,通过紫外诱变筛选得到一株γ-谷氨基甲酰胺合成酶高产菌株UV-19,其酶活提高32.54%。以突变株UV-19为供试菌株,对γ-谷氨基甲酰胺合成酶的发酵条件进行优化。首先利用Plackett-Burman设计筛选出影响较大的4个因素:葡萄糖、蛋白胨、起始pH值、装液量。在此基础上再利用CCD响应面分析法进行优化,得到最佳产酶培养条件为(g/L):葡萄糖15、蛋白胨12、NaCl 5.0、MgSO4.7H2O 0.2、K2HPO4.3H2O 0.5、甲胺盐酸盐1.0g/L、起始pH值6.5、装液量72mL/250mL。该优化条件下进行产酶培养,假单胞菌发酵产γ-谷氨基甲酰胺合成酶酶活力可达32.68U/mL。     

海洋中海藻糖产生菌的筛选及发酵条件优化

从180余份海水、海泥样品中筛选得到60株产海藻糖较高的菌株,编号为2-14的菌株海藻糖产量最高,为127.9mg/g cell。对2-14菌株进行形态特征、培养特征及生理生化试验,鉴定该菌株为红酵母属(Rhodotorula sp.)。研究摇瓶发酵条件对红酵母海藻糖产量的影响,结果为:初始pH5.5,发酵温度28℃,装液量75mL(250mL三角瓶中)。采用优化后发酵条件红酵母海藻糖产量为193.3mg/g cell,优化前对照值为132.1mg/g cell,优化后的结果是优化前的1.46倍。在5L发酵罐中培养得到最佳发酵时间为54h,发酵罐培养发酵液中海藻糖含量最高达2.5g/L,为摇瓶培养的1.6倍。     

Screening of iron- and zinc-enriched yeast strain and optimization of cultivation conditions

Saccharomyces cerevisiae LN-17 was selected from 26 kinds of primary yeast strains that belong to different genera and species. The iron- and zinc-enriched capability of strain LN-17 was higher than the others. The highest iron and zinc contents of the strain were obtained when the strain grew up under the following conditions: The strain was incubated (5%, v/v) in 50 mL wort medium (pH 6.0) with 100 mg/L Fe ion and 120 mg/L Zn ion. The medium was loaded into a 250-mL Erlenmeyer flask and shaken in a rotary shaker (200 rpm) at 30°C for 60 h. Ferrous sulfate and zinc sulfate were chosen as the source of Fe and Zn. The Fe and Zn contents of the dry cells were determined by atomic absorption spectrum analysis. Under the optimized cultivation conditions, the Fe and Zn contents reached 7.854 mg/g dry cells and 4.976 mg/g dry cells.     

一株溴氰菊酯降解菌的分离鉴定及其降解条件优化

【背景】拟除虫菊酯类农药的降解已成为食品安全和环境卫生领域的研究热点,而生物降解被认为是一种绿色高效的解决方法。【目的】从长期受拟除虫菊酯类农药污染的草莓根系土壤分离一株溴氰菊酯(deltamethrin,DM)降解菌,并优化其培养基及降解条件,从而提高DM降解菌的降解效率。【方法】采用富集驯化、分离纯化法筛选DM降解菌,通过形态学和生理生化特征,以及16S rRNA基因序列分析进行鉴定。通过Plackett-Burman因素筛选试验、最陡爬坡试验和Box-Behnken试验优化菌株降解条件。【结果】筛选获得一株DM降解菌LH-1-1,96h对DM(100mg/L)的降解率为53.43%,经鉴定为琼氏不动杆菌(Acinetobacter junii);通过优化后,在DM浓度75mg/L、胰蛋白胨3 g/L、pH值6.8、硫酸铵1.5 g/L、氯化铁0.01 g/L、接种量为5%(体积比)、菌龄12 h、培养温度30℃条件下,菌株LH-1-1对DM降解率达82.36%,较未优化前提高了28.93%。【结论】A. junii LH-1-1具有较高的DM降解能力,该菌可为生物修复受DM或拟除虫菊酯类农药污染的环境提供优良的微生物资源。     

Improving the production of S-adenosyl-L-methionine in Escherichia coli by overexpressing metk

S-adenosyl-L-methionine (SAM) has important applications in many fields including chemical therapy and pharmaceutical industry. In this study, the recombinant Escherichia coli strain was constructed for effective production of SAM by introducing the SAM synthase gene (metK). This strain produced 34.5?mg/L of SAM in basic medium in shake flask. Yeast extract, pH, and loaded volume had a significant positive effect on the yield of SAM. Their optimal values were 35?g/L, 7.5, and 30?mL, respectively. The final conditions optimized were as follows: glucose 20, g/L; peptone, 40?g/L; yeast extract, 35?g/L; NaCl, 10?g/L; MgSO₄, 1.2?g/L; L-methionine, 1?g/L; rotate speed, 220?rpm; loaded volume, 30?mL; inoculation, 1%; temperature, 37°C; and initial medium, pH 7.5. The recombinant strain produced 128.2?mg/L of SAM under the above conditions in shake flask. The production of SAM in a 5?L fermentor was also investigated. The maximal biomass of the recombinant strain was 60.4?g/L after the cells were cultured for 20?hr, and the highest yield of SAM was 300.9?mg/L after induction for 8?hr in a 5?L fermentor. This study provides a good foundation for the future production and use of SAM.     

微生物转化连翘苷制备连翘脂素的研究

本文旨在开发一种微生物转化工艺,将连翘苷转化为活性更高的连翘脂素.结果从土壤中分离筛选到一株桔青霉(Penicillium citrinum)LB菌株,转化连翘苷为连翘脂素的专一性较高.经培养基主要组成和转化条件优化,得出较佳的产酶培养组成为:蔗糖7 g/L,(NH4)2 SO45 g/L,NaCl 5 g/L,KH2 PO45 g/L,MgSO41 g/L,MnSO40.5 g/L,pH 6.0.LB菌株经产酶培养后,过滤收集菌体悬浮于2倍发酵液体积的磷酸盐缓冲液中,加入2 g/L的底物连翘苷,于30℃、200 r/min转化20 h,连翘脂素的转化得率可达94.1%.利用微生物将连翘苷转化为连翘脂素,具有方法简单、转化得率高、产物容易纯化和副产物少等优点,有潜在的工业化应用价值.     

代谢工程改造大肠杆菌合成丁二酸及发酵罐放大工艺

【背景】Escherichia coli AFP111发酵生产丁二酸时大量副产乙酸,丁二酸得率低。【目的】代谢工程改造EscherichiacoliAFP111,提高丁二酸得率,降低副产物乙酸的生成,建立100 L规模的丁二酸发酵工艺。【方法】一步同源重组敲除乙酸合成途径关键酶基因,改造丁二酸合成途径关键酶启动子实现过表达;单因素优化5L发酵罐培养条件。【结果】敲除乙酸产生途径编码乙酸激酶和磷酸转乙酰酶的基因ackA-pta、苏氨酸脱羧酶和2-酮丁酸甲酸裂解酶的基因tdcDE获得SX02菌株,摇瓶发酵条件下其乙酸产量下降了53.42%,丁二酸得率提高9.85%。在SX02菌株基础上,经启动子改造过表达编码葡萄糖激酶的基因glk后获得菌株SX03,其Glk酶活性提高3.66倍,乙酸产量下降了31.62%,丁二酸得率提高8.28%。SX03菌株发酵生产丁二酸在5 L发酵罐进行放大,其乙酸产量为3.97 g/L,丁二酸得率为1.62 mol/mol葡萄糖,相比出发菌株的乙酸产量下降了75.76%,丁二酸得率提高19.12%。在5L发酵罐上对比研究了中和剂Na2CO3和NaOH混合液替换碱式MgCO3的发酵效果,并优化了发酵pH、搅拌转速和葡萄糖浓度,获得如下最适发酵条件:pH6.8,搅拌转速250r/min,葡萄糖100g/L,发酵结束时乙酸产量为2.24 g/L,丁二酸得率为1.66 mol/mol葡萄糖。中和剂替换优化后乙酸产量下降了20.65%,丁二酸得率提高2.47%。菌株SX03发酵工艺进一步在100 L发酵罐上实现放大,其乙酸产量为1.91 g/L,丁二酸得率为1.30 mol/mol葡萄糖。【结论】通过代谢工程改造的大肠杆菌,其副产物乙酸含量显著下降,丁二酸得率提高,并在5 L和100 L发酵罐上实现了工艺放大,展现出较大的工业化利用潜力。     

响应面-满意度函数优化重组大肠杆菌产NMN转移酶发酵条件

重组大肠杆菌Escherichaia coli能高效表达NMN转移酶,以此为出发菌株,以菌体生长量OD600和NMN转移酶的活力为响应值,对重组大肠杆菌产NMN转移酶的发酵条件进行优化.首先以Plackett-Burman实验设计优化筛选出3个主要影响因子:胰蛋白胨、甘油、MgSO4;随后以Box-Behnken中心组合设计建立上述3个因子对OD600和NMN转移酶活力水平的数学模型;最后通过满意度函数获得最佳发酵条件为:酵母粉30 g/L,胰蛋白胨10.5 g/L,甘油3.49 mL/L,MgSO40.45 g/L,K2 HPO440.5 g/L,KH2 PO46.0 g/L,NH4 Cl 1.5 g/L,NaCl 0.6 g/L,接种量1.5%,诱导时间12 h.在该优化条件下,菌体生长和产酶水平均获得了显著的提升.重组NMN转移酶的活力水平从8.85 U/mg提高到15.48 U/mg,菌体生长量OD600从4.85提高到6.01,提高幅度分别为74.92%和23.92%.     

红曲多糖液态发酵条件与抗氧化活性的研究

对1株高产胞外多糖红曲霉菌株Mr-70的液态发酵条件和粗多糖抗氧化活性进行了初步研究,得到菌株Mr-70优化后的发酵工艺条件为葡葡糖60 g/L,蛋白陈20g/L,K2HPO410 g/L,MgSO4 · 7H20 1.1g/L,PH 6.5,在摇床转速200 r/min,温度32℃的条件下培养96 h,胞外粗多糖产量...     

Fermentation of corn fibre sugars by an engineered xylose utilizing Saccharomyces yeast strain

The ability of a recombinant Saccharomyces yeast strain to ferment the sugars glucose, xylose, arabinose and galactose which are the predominant monosaccharides found in corn fibre hydrolysates has been examined. Saccharomyces strain 1400 (pLNH32) was genetically engineered to ferment xylose by expressing genes encoding a xylose reductase, a xylitol dehydrogenase and a xylulose kinase. The recombinant efficiently fermented xylose alone or in the presence of glucose. Xylose-grown cultures had very little difference in xylitol accumulation, with only 4 to 5g/l accumulating, in aerobic, micro-aerated and anaerobic conditions. Highest production of ethanol with all sugars was achieved under anaerobic conditions. From a mixture of glucose (80g/l) and xylose (40g/l), this strain produced 52g/l ethanol, equivalent to 85% of theoretical yield, in less than 24h. Using a mixture of glucose (31g/l), xylose (15.2g/l), arabinose (10.5g/l) and galactose (2g/l), all of the sugars except arabinose were consumed in 24h with an accumulation of 22g ethanol/l, a 90% yield (excluding the arabinose in the calculation since it is not fermented). Approximately 98% theoretical yield, or 21g ethanol/l, was achieved using an enzymatic hydrolysate of ammonia fibre exploded corn fibre containing an estimated 47.0g mixed sugars/l. In all mixed sugar fermentations, less than 25% arabinose was consumed and converted into arabitol.