微生物发酵法产脱落酸的研究进展

脱落酸是一种以异戊二烯为基本单位的酸性倍半萜类物质,是一种重要的植物激素,在调节植物生长代谢、抵抗农业自然灾害、增加农作物产量等诸多方面发挥着重要的作用,具有非常广阔的应用前景。本文介绍了天然脱落酸的生物合成途径,并从发酵菌株、发酵底物、发酵工艺、分离提取等方面阐述了微生物发酵产脱落酸的研究进展。同时讨论了天然脱落酸发酵过程中存在的问题,如初始菌株产量低、发酵周期长、发酵工艺不稳定、产物提取效率低等,因此本文在此基础上指出,筛选优良性状的生产菌株、进一步研究脱落酸生物合成途径中关键酶的酶学性质以及进一步开发脱落酸的先进发酵与分离提取工艺是今后研究的重点方向。     

赤霉素GA4+7在5000L发酵罐中的中试发酵工艺

[目的]探索赤霉素GA4+7在5000 L发酵罐中的中试发酵工艺条件.[方法]赤霉素GA4+7发酵培养基配方和发酵条件的优化筛选研究,分别在摇瓶条件下和在5000 L发酵罐中进行,采用多因素不同水平的正交试验设计.赤霉素GA4+7发酵单位的检测采用HPLC法.[结果]获得了赤霉素GA4+7发酵培养基优化配方:淀粉+葡萄糖为9.0％+1.0％、花生粉+黄豆粉为1.2％+0.6％、磷酸二氢钾和硫酸铵为0.2％和0.01％;获得了赤霉素GA4+7在5000 L发酵罐中优化的发酵条件:温度32℃、发酵通气量V(空气)∶V(发酵液)为0.4∶1、种子罐接种摇瓶种液400 mL、种子罐培养液中硫酸铵含量为0.05％、发酵罐补糖、种子罐种龄和发酵移种量分别为38 h和12％、发酵罐中添加碳酸钙量为0.2％.[结论]成功地探索到赤霉素GA4+7在5000 L发酵罐中发酵工艺条件,GA4+7在5000 L发酵罐中发酵效价达到788 mg/L,且GA4/GA7比例为1.06,GA4+7产品质量好,该工艺条件为大罐发酵生产赤霉素GA4+7奠定了较坚实的基础.     

赤霉素生产中若干问题的讨论

一、前言赤霉素是一类高效植物生长调节剂,广泛存在于各种植物体内,具有调节植物体内营养、生长和生殖的效应。目前发现的植物内源赤霉素(激素)同系物已有50多种,其中生理活性较大的有GA_3、GA_4、GA_7、GA_(14)等,GA_3的生理活性最强,其分子式为C_(19)H_(22)O_6,分子量为346.37(按1977年国际原子量),其化学结构式(赤霉素A_3)如下图:     

L-乳酸的微生物发酵

L-乳酸作为一种环境友好新兴材料,广泛应用于制药、食品、皮革等工业中,由于可降解塑料生产量的增加,对于其需求也越来越多。乳酸生产的主要方法是微生物发酵法,包括细菌发酵法和根霉发酵法,本文对于这两种微生物发酵方法进行了综述。     

增加溶氧提高赤霉素发酵质量

赤霉素发酵过程中溶解氧的含量对赤霉菌生长有很大的影响。通过改善通气质量、改进搅拌等措施。 提高发酵前期的溶氧,可使赤霉菌在对数生长期内氧的供应得到保证。为其代谢产物赤霉素的产生 打好基础,从而达到降低生产成本的目标。     

微生物发酵产氢技术研究进展

化石能源的短缺和环境污染的出现使可再生能源和清洁能源的开发变得十分迫切。由于氢气是一种清洁、高效的能源,所以有关微生物发酵制氢逐渐成为关注的热点。本文主要介绍氢气的微生物代谢途径及关键酶,重点综述极端高温产氢菌群及发酵产氢工艺,并展望利用复杂非粮原料产氢菌及其工艺技术,结合系统生物学和合成生物学对现有产氢菌提高生产效率和构建产氢新途径提供理论指导。     

厌氧微生物发酵产氢菌种筛选的研究

生物制氢技术因具有无污染、成本低、可再生等诸多优点,目前在新能源的研究利用中占有日趋重要的位置.本文对几种茵种进行了产氢性能的鉴定,以葡萄糖为基质在厌氧条件下培养,进行了产氢茵的筛选,并对初始培养pH值、培养基底物葡萄糖浓度等条件优化及产氢菌的保存进行了探索.     

赤霉素的树脂分离试验

本文介绍利用分光光度计分析赤霉素含量，以及用大孔树脂为载体吸附赤霉素，并用脱附剂进行洗脱，从而达到赤霉素与水分离的实验室试验方法。     

利用微生物混合静止发酵降低赤霉素萃余液中COD含量

[目的]降低赤霉素萃余液中COD含量,减轻赤霉素萃余液对废水处理站运行负荷的压力。[方法]以赤霉素萃余液为基础培养基,适当添加糖蜜和KH2P O4后,混合接入耐盐耐酸的酵母菌与乳酸菌,进行二菌群的混合静止发酵。[结果]酵母菌与乳酸菌均能在赤霉素萃余液中生长繁殖;静止培养5 d后,赤霉素萃余液COD从100 g/L以上下降至50~60 g/L,COD降解率达50%左右,酵母乳酸菌体固含量达到10%以上。[结论]利用微生物混合静止发酵降低赤霉素萃余液中COD含量,其技术路线初步可行。     

Fermentative production of fumaric acid from Eucalyptus globulus wood hydrolyzates

Fumaric acid (FA) was produced from Eucalyptus globulus wood by successive steps of hydrothermal processing (to solubilize hemicelluloses and to increase the susceptibility of solids to enzymatic hydrolysis), enzymatic hydrolysis and fermentation with Rhizopus arrhizus DSM 5772. For comparative purposes, additional fermentations were carried out using synthetic media. Single stage fermentation of synthetic media led to a medium containing 11.8 g FA L^?1 (Y_P/S = 0.60 g g^?1). Operating in fed batch mode, the fourth stage increased the FA concentration from 19.7 up to 43.6 g L^?1 (Y_P/S = 0.71 g g^?1). Hydrolyzate fermentation in a single stage resulted in lower fumaric acid concentration (9.65 g L^?1) and yield (0.35 g g^?1). Additional fermentations were carried out in media made with hydrolyzates subjected to membrane processing, adsorption or ion exchange. The highest yield (Y_P/S = 0.44 g g^?1) was reached in media made up of ion‐exchange treated hydrolyzates and a commercial glucose solution in proportion 85/15 w/w. Copyright © 2011 Society of Chemical Industry     

高浓度有机废水发酵法制取氢气技术

利用两相厌氧高浓度有机废水处理的产酸相制取氢气技术引起世界的普遍关注。介绍了厌氧发酵生物制氢系统的产氢机理、工艺流程与设计、工程控制参数等许多技术问题。认为发酵产氢微生物有丁酸型发酵、乙醇型发酵和甲酸裂解等3种产氢代谢途径。工艺设计以活性污泥的混合培养为主要形式,也发展了细菌的纯培养或辅之细胞固定化工艺。目前已经分离出肠杆菌属(Enterobacter)、梭状芽孢杆菌属(Clostridium)、柠檬酸菌属(Citrobacter)和新型乙醇型发酵产氢细菌等菌属的发酵产氢细菌,这些菌种除了可以纯培养制氢外,还可以进行投入反应系统进行生物强化和细胞固定化技术应用。乙醇型发酵生物制氢理论(双碳发酵产氢学说或理论)指导下发酵法混合培养生物制氢工艺已分别进行了小试和中试,并将进入生产示范工程阶段。     

不同底物种类对厌氧发酵产氢的影响

利用间歇批次分别研究了葡萄糖、蔗糖、乳糖、淀粉、纤维素和蛋白胨对厌氧发酵产氢的影响。研究结果表明,葡萄糖和蔗糖是最好的产氢底物,1mol葡萄糖氢气产量为1．71mol,产氢速度16．5mL／h,能量转化率为12．5％。产氢能力稍差一点是乳糖和淀粉,而纤维素和蛋白胨不能直接作为产氢底物。     

产朊假丝酵母流加发酵法生产谷胱甘肽

研究了产朊假丝酵母在不同葡萄糖浓度下的谷胱甘肽(GSH)分批发酵过程,在此基础上进一步考察了重复补料、恒速流加和指数流加等不同培养方式对GSH发酵生产的影响. 结果发现,这几种培养方式都可以实现酵母细胞和GSH的高产. 综合比较,无论是从细胞还是从GSH的产量、得率和生产强度的角度来看,指数流加都是较为理想的选择. 经过48 h的指数流加培养,细胞干重达到40.9 g/L, GSH产量和胞内GSH含量分别达到857.2 mg/L和2.25%.     

Fermentative production of mitomycins by Streptomyces caespitosus

Production of mitomycin antibiotics by Streptomyces caespitosus was increased by the utilisation of molasses (1.0%) treated with 0.01 % potassium ferrocyanide and corn steep liquor (0.9 %). Three different fermentation media were used for the fermentation production of mitomycins. Appropriate amounts of ammonium sulphate, soluble starch, ferrous sulphate, magnesium sulphate, potassium dihydrogen phosphate, sodium chloride and calcium carbonate increased the antibiotic yield when added to the fermentation medium containing molasses and corn steep liquor. The addition of some individual amino acids, vitamins and organic acids to a base fermentation medium did not improve or increase its performance.     

Fermentative production of puromycin by Streptomyces alboniger

Two strains of Streptomyces alboniger NRRL B-1832 and 2403 were used for the biosynthesis and production of puromycin using different media. Streptomyces alboniger NRRL B-2403 produced more puromycin than NRRL B-1832 on medium composed of (amounts in g/1), soybean meal 10.0; corn steep 20.0; dextrin 10.0; NaCl 5.0; CaCO₃ 2.0, and K₂HPO₄ 2.0. When the carbon and nitrogen sources of the basal medium were replaced by different carbon and nitrogen sources it was found that dextrin, sucrose, starch and maltose favoured the production of higher titres of puromycin, while generally organic nitrogen sources such as soybean meal and fodder yeast (40.0 and 50.0% total nitrogen) stimulated puromycin yield. On the evidence of their chemical compositions and because they are cheap and produced locally Egyptian black, strap molasses and fodder yeast are preferably used in medium for the production of puromycin. The other conditions favouring and controlling the production and biosynthesis of puromycin by fermentation were investigated.     

Lipolytic enzyme production in batch and fed‐batch cultures of Ophiostoma piceae and Fusarium oxysporum

Lipase and esterase production by Ophiostoma piceae and Fusarium oxysporum were enhanced and extended by developing a fed‐batch process in stirred tank reactors. Fed‐batch strategy improved lipolytic enzyme production from Ophiostoma piceae in both 2 and 20 dm³ stirred tank reactors. However, fed‐batch fermentation of Fusarium oxysporum in the 2 dm³ reactor was more effective than both batch and fed‐batch fermentations in the 20 dm³ reactor. When a medium composed of only carbon and nitrogen source was intermittently fed to the cultures, the maximum specific lipase activity was improved by more than 80% and 35% in Ophiostoma piceae and Fusarium oxysporum cultures respectively. The maximum specific esterase activity was improved by 20% and 15% in Ophiostoma piceae and Fusarium oxysporum cultures respectively. The duration of production for both fungi extended from 144 to 216 h compared with a batch culture under the same condition. © 2000 Society of Chemical Industry     

玉米秸秆厌氧发酵生物制氢流变学性质的研究

主要探讨了发酵液的流变性质对发酵过程的影响.实验结果表明:发酵液为非牛顿型流体,其粘度和密度由细胞浓度和发酵底物有机负荷共同决定.根据剪切和紊流程度对发酵反应的影响,确定此反应的搅拌速率为100 r/min.