聚半乳糖醛酸酶高产菌的产酶条件研究

通过单因素及正交试验对米曲霉（Aspergillus orza）C491产生聚半乳糖醛酸酶的发酵条件进行了优化。该菌株的摇床发酵滤液以桔子果胶为底物时酶活力可达344．8U／mL。产酶最适培养基组成为：麦芽汁（糖度6％）中添加6％桔皮粉,2％硫酸铵（w/v）。最适培养条件：起始pH4（灭菌前）,30℃,r/min,培养112h。Tween80可以促进C－491产酶。     

木霉LaTr 01菌株产漆酶发酵的条件

从华南地区采集土样,采用愈创木酚平板筛选产漆酶菌株,获得了一株短周期产漆酶的小型丝状真菌。通过观察菌落特征、生长情况以及显微镜下菌丝和孢子的形态,初步鉴定该菌株为木霉属的一个种（Trichodermaspp、）,命名为木霉LaTr01菌株。通过单因素方法研究该菌产漆酶的发酵条件,结果表明：LaTr01的产酶培养基以麦芽糖为最佳碳源;以酵母提取物为最适氮源;培养24h后加入Cu“比培养开始加入Cu ^2＋LaTr01产酶活高出约1倍。采用麦芽糖、酵母提取物、Cu^2＋浓度L9（3^3）的正交试验优化漆酶发酵条件,结果表明,氮源是影响该菌产漆酶的最重要因素,碳源次之,Cu^＋浓度影响较小;LaTr01菌株产生漆酶的最佳条件为：5g／L酵母提取物、20g/L麦芽糖、1．5mmol／LCu^2＋,Cu^2＋加入时间为培养24h后。在优化的培养条件下,该菌酶活可达480．556U／L。     

泡盛曲霉CAU33固体发酵产β-1,3-1,4-葡聚糖酶发酵条件优化

利用单因素实验法优化了泡盛曲霉(Aspergillus awamori)CAU33利用农业废弃物固体发酵产β-1,3-1,4-葡聚糖酶的发酵条件。产酶的条件包括碳源种类、初始水分含量、氮源种类、初始p H、表面活性剂、培养温度和发酵时间。进一步运用响应面分析法优化了其中主要因素,得到最佳产酶条件为:啤酒糟为碳源、含水量为81.6%、吐温60添加量20g/L、大豆蛋白胨添加量25g/L、自然p H、35℃下培养6d。在优化后的发酵条件下,最大产酶水平达到40 832.9U/g。泡盛曲霉固体发酵产β-1,3-1,4-葡聚糖酶的酶活力高,工业化生产和应用潜力大。     

南极交替单胞菌R11-5产卡拉胶酶的发酵条件优化

【背景】极地寒冷环境中发现了大量具有潜在应用前景的冷适应酶,同时也存在种类繁多的海藻多糖降解菌,因此极端环境微生物是筛选获得新颖、高效多糖降解酶的重要新源泉。由于筛选培养基通常并非野生菌发酵产酶的最优条件,为了使野生菌的产酶效率达到最高,需要对其培养条件进行优化,从而为其深入研究及开发利用提供依据。【目的】对一株产卡拉胶酶的南极菌株进行种属鉴定,并采用响应面法对该菌的发酵产酶条件进行优化。【方法】通过16SrRNA基因对产卡拉胶酶的南极菌株进行种属鉴定,采用响应面法优化南极菌株产酶发酵条件。【结果】该南极菌属于交替单胞菌属(Alteromonas),命名为交替单胞菌R11-5。发酵条件优化结果显示,7个环境因子影响交替单胞菌R11-5的产酶量。利用Design-Expert软件中的Plackett-Burman设计实验,筛选出影响交替单胞菌R11-5产酶量的4个主要因素分别为培养温度、牛肉膏浓度、卡拉胶浓度和Ca~(2+)浓度。通过Box-Behnken设计和响应面分析得到交替单胞菌R11-5最佳产酶发酵条件为:温度15.0°C,牛肉膏浓度11.0 g/L,卡拉胶浓度3.0 g/L,Ca~(2+)浓度5.0 mmol/L。优化后发酵上清液酶产量达到87.193 U/mL,与优化前相比提高了1.8倍。【结论】响应面法提高了南极交替单胞菌R11-5卡拉胶酶的产量,为其开发应用提供了科学依据。     

Serratia sp. PS-2产几丁质酶发酵条件研究

采用平板透明圈法,从海洋红树林根泥筛选得到一株产几丁质酶较强沙雷氏菌株Serratia sp. PS-2.为实现工业化生产几丁质酶,考察了以几丁质为诱导剂,碳源、氮源、NaCl 浓度、培养温度、时间、培养液酸碱度、通气量和搅拌速度等对产酶的影响,得到了优化的发酵条件.5L发酵罐实验表明,该菌株可在发酵72h内达到产酶高峰,最高酶活力可达到0.68 U/mL.     

右旋糖酐酶产生菌的筛选及其酶学性质的比较研究

从3162株真菌中筛出具有右旋糖酐酶话力的菌株528株,其中黄柄白曲霉(Asp. Flavi-pes)、蠕形青霉(Pen. Vermiculatum)、产黄青霉(Pen. Chrysogerum)和构巢曲霉(Asp. Nid-ulans)也产该酶,这在文献中尚未见报道。通过复筛,从中选出5株,它们分属黄柄白曲霉(Asp. Flavipe、二株)、肉色曲霉(Asp.carneus)、焦曲霉(Asp. Ustus)和淡紫拟青霉(Paecilomyces lilacinus)(各一株)。对它们的产酶特性作了一系列比较研究,发现所有酶的最适温度皆为50--55℃,最适作用PH为5.0—5.5,酶解最终产物是异麦芽塘、异麦芽三糖及少量葡萄糖,故它们皆属内切型右旋糖酐酶。此外它们在温度和PH稳定性、其它酶活力存在的情况、对不同底物作用的情况、凝胶电泳模式、金属离子和一些蛋白质变性剂的影响等方面都有一些差异。通过比较发现,由淡紫拟青霉8523菌产生的右旋糖酐酶具有较好的酶学性质：它在50"0保温24小时和60℃保温1小时,剩余话力分别为95％和90％,在pH 3．5—1 0．5很宽的范围内是稳定的,此外它对SDS和脲的耐受性也较其它菌株的酶好。     

中性蛋白酶高产菌株的筛选及产酶酶系分析

目的:满足水产中对中性蛋白酶的需求。方法:以实验室保藏的米曲霉ZW为出发菌株,经Co60定向诱变,通过透明圈法初筛、摇瓶发酵复筛,筛选中性蛋白酶活力高的菌株,并对其进行产酶酶系分析。结果:筛选到的米曲霉ZW-06产中性蛋白酶酶活可达15000U/g干曲,比诱变前酶活提高了74%,是目前国内报道的固体发酵产中性蛋白酶活力最高的菌株;经过10代传代之后,酶活力仍保持稳定。通过对米曲霉ZW-06进行产酶酶系分析,发现发酵产物中除了有较高的中性蛋白酶酶活,还有较高的木聚糖酶和酸性纤维素酶酶活,酶活分别达到49879U/g干曲和21099U/g干曲。结论:米曲霉ZW-06在饲料工业中有很大     

大豆异黄酮糖苷酶产生菌培养条件优化及转化

将经过筛选的产大豆异黄酮糖苷水解酶的菌株米曲霉3042经过单因子及正交试验,确立了产酶的最适培养基配方为：玉米芯＋麸皮4%,（NH4）2SO40.1%,水扬苷0.01%,KH2PO40.1%,Vc 0.1%,MgSO40.1%.产酶的最佳培养条件为：发酵培养基起始pH 6.0,发酵温度27℃,摇床转速160r/min,发酵时间84 h时酶活力最高.粗提取的大豆异黄酮经发酵液转化后,其结合态含量降低,游离态含量增加.     

粘质沙雷氏菌产几丁质酶发酵条件的研究

目的：通过对粘质沙雷氏菌发酵条件的优化,提高其产几丁质酶的能力。方法：以实验室保存菌种粘质沙雷氏菌S418为对象,通过单因素试验和三因素三水平正交试验筛选出了菌株S418产几丁质酶的最佳培养基配方及培养条件。结果：该菌种产酶的最佳发酵条件：0.2%（w/v）胶体几丁质,1%蛋白胨,0.05%KH2PO4,在28℃、pH7.0、接种量6%,培养72h,酶活达到5.49U/mL。结论：优化后菌株S418产几丁质酶的条件。     

去壁酶与酶解方式对曲霉原生质体释放的影响

研究了纤维素酶、蜗牛酶、溶菌酶以及菌丝体培养方式和酶解方式对黑曲霉和米曲霉菌丝释放原生质体的效应。发现黑曲霉菌丝原生质体制备最佳条件为固体透析培养菌丝体,2%纤维素酶,在平皿中,28℃和80r/min条件下酶解3h;米曲霉原生质体制备最佳条件为2%纤维素酶+1%蜗牛酶+5mmol/L二硫苏糖醇,酶解时间6h,其它条件与黑曲霉的相同。     

离子注入改良维生素C二步发酵混合菌研究(Ⅱ)2-酮基-L-古龙酸高产菌系IPPM-1028发酵条件研究

考察了不同碳氮源、碳氮比、金属离子和有机溶剂等以及环境因子,如起始ｐＨ,通气量和种龄等对高产菌系ＩＰＰＭ－１０２８发酵水平的影响。实验结果表明,适宜的碳氮比对产酸有明显的影响;在培养基中加入适量的金属离子如Ｍｎ２＋、Ｃｅ３＋、Ｃｅ４＋或Ｌａ２＋以及增加通气量均有利于２－ＫＬＧ的产生。二甲苯和乙酸己酯对产酸也有一定的刺激作用。发酵周期一般为６０～６４ｈ,２－ＫＬＧ浓度可达７６ｇ／ｌ左右,转化率约为９５％。     

Production of isoamylase by Pseudomonas amyloderamosa mutant strain JD210

Nutritional requirements for the production of isoamylase by Pseudomonas amyloderamosa mutant strain JD210 were investigated. The optimal initial pH for enzyme production in shake-flask cultivation was 5.0. Maltose and soybean protein hydrolyzate were found to be the best carbon source and nitrogen source, respectively. The enzyme production was drastically inhibited by Zn+2 and Cu+2. Other metal ions phosphates and surfactants exhibited no significant inhibitory or accelerating effect on enzyme production. According to auxanography and single omission experiments, proline and isoleucine were required for growth. The supplement of 0.1% proline increased enzyme production by around 30% compared with no addition.     

溶剂稳定性蛋白酶产生菌Bacillus licheniformis YP1的发酵优化

溶剂稳定性蛋白酶产生菌Bacillus licheniformis YP1分离自油田土样。考察了碳源、氮源、金属离子等营养因素对YP1菌株发酵产溶剂稳定性蛋白酶的影响。YP1菌株发酵产胞外蛋白酶的最佳碳源为淀粉,果糖、甘露糖和乳糖显著抑制产酶;最佳氮源为酵母膏,干酪素、酵母粉和牛肉膏促进产酶,玉米浆和尿素显著抑制产酶。Mn^2＋可以显著促进酶活,Mg^2＋可以促进产酶,在初步优化的培养条件下,YP1菌株的胞外蛋白酶产量达980U。     

Improved extracellular transferase enzyme production by Aspergillus foetidus for synthesis of isooligosaccharides

Aspergillus foetidus was used to produce transferases that can be utilized in the synthesis of isooligosaccharides. Maltose and corn steep liquor were found to be the best carbon and nitrogen substrates at optimum concentration of 1% and 3% respectively. Surfactant Tween 80 and metal ions including Fe²⁺, Zn²⁺, Mg²⁺ and Cu²⁺ were found to have no obvious effect on the enzyme productivity. Uncontrolled pH starting with an initial value of 5.0 gave the highest transferase productivity compared with pH controlled at constant levels and control after natural fall. The optimum temperature was found to be 30v°C. Enzyme activity increased 8 fold in reactors, with better aeration and agitation condition, as compared to shake flask. The morphology of the organism was highly dependent on the nitrogen source and had great influence on enzyme productivity.     

Isolation of a novel lipase producing fungal isolate Aspergillus fumigatus and production optimization of enzyme

Abstract

Fungal lipases occupy a place of prominence among biocatalysts owing to their novel, multifold applications and resistance to high temperature and other operational conditions. In the present study, Aspergillus fumigatus isolated from oil-contaminated soil produced good amount of lipase activity with galactose (1%) as carbon source and peptone (0.1%) as nitrogen source after 72?h of incubation in the production medium at 45?°C and pH 10.0. The isolated enzyme was found to give its optimum reaction temperature at 40?°C and pH 9.0 with the substrate used as p-nitrophenyl benzoate. The activity of lipase was inhibited by the presence of metal ions. A 6.68-fold increase for lipase production was obtained by one variable at a time. Based on the findings of present study, lipase of A. fumigatus is a potential lipase and a candidate for industrial applications such as bioremediation, detergent, leather and pharmaceutical industries.     

酿酒酵母菌培养条件的研究

目的：优化酿酒酵母液体发酵得到菌体的最佳条件。方法：通过单因素试验,以吸光度为指标,研究碳源、氮源、接种量、pH值及无机离子对酿酒酵母菌生长的影响。结果：酿酒酵母生长的最佳碳源是葡萄糖,最佳氮源是蛋白胨,最佳接种量2％,最佳初始pH为4．5,添加无机盐硫酸亚铁能够促进其生长。结论：得到了酿酒酵母液体生长的最佳培养基配方。     

L-histidine utilization in Aspergillus nidulans.

Histidase activity rather than uptake of L-histidine is the limiting factor for the utilization of histidine as the sole nitrogen source for Aspergillus nidulans. Histidine cannot act as the sole carbon source, and evidence is presented indicating that this is attributable to an inability to convert histidine to L-glutamate in vivo. It has been shown that this fungus lacks an active urocanase enzyme and that histidine is quantitatively converted to urocanate, which accumulates in the extracellular medium. The use of histidine as a nitrogen source is regulated by nitrogen metabolite repression control of histidase synthesis. In addition, evidence for a requirement for a carbon source for histidase synthesis and for a minor form of control by nitrate is presented. The activity of the histidase enzyme is inhibited by micromolar concentrations of the product urocanate and by physiological levels of L-glutamate and L-glutamine.