共查询到19条相似文献,搜索用时 78 毫秒
1.
利普司他汀(lipstatin)是一种β-内酯分子,能选择性抑制胰脂肪酶的活性,从而减少小肠脂肪的吸收。分析表明,一个利普司他汀分子与一个脂肪酶分子结合,通过活性部位丝氨酸残基的酰化来抑制胰脂肪酶的催化活性。利普司他汀由毒三链霉菌(Streptomyces toxytricini,简称S. toxytricini)生产的一种天然产物。本文综述了利普司他汀的结构特点,分析了利普司他汀市场应用现状,着重论述了发酵法生产利普司他汀的研究进展;提出生物合成利普司他汀的机制尚不清楚,但酰基辅酶A羧化酶(ACCase)复合物在利普司他汀生物合成中起着关键作用。最后,指出当前存在的问题并对代谢工程在利普司他汀产生菌发酵中的应用进行概述,对今后的研究趋势进行了展望。 相似文献
2.
发酵过程优化问题通常包含有互相冲突的多重优化目标,另外反应本身具有诸多复杂性。提出一种基于Pareto的分布式Q学习多目标策略,用以求解赖氨酸分批补料发酵过程流加速率轨迹的Pareto最优解。该策略中,Q学习算法和Pareto排序法将结合来产生非支配解集,并使之逼近真实的Pareto前沿,利用奖赏机制来描述多重目标之间的关系,并同时使用多组含有随机初始值的agent共同作用改善搜索能力。将所提出的方法应用于赖氨酸分批补料发酵过程的优化中,并与粒子群优化进行了对比,验证策略的性能。 相似文献
3.
通过对补料时间、方式和补料液浓度变化(特别是补加氮源)对D-核糖发酵过程影响,确定了D-核糖发酵的补料工艺。按此工艺条件,发酵的时间为72 h,D-核糖的产量93.83 g/L,剩余葡萄糖浓度为4 g/L,转化率为0.284 3 g/g,生产强度为1.303 g/(L.h)。与不补料相比,D-核糖产量提高了95.9%。 相似文献
4.
5.
6.
在林肯链霉菌发酵生产林可霉素的过程中,适量补入碳源及氮源,能够稳定整个发酵过程的供给与生产菌,使林可霉素合成酶大量增殖。在30 L发酵罐上对林可霉素发酵补料工艺进行研究,通过在发酵2~3 d时补料,在玉米浆1%、高温豆粉2%、麸质粉2%、硫酸铵0.2%时,使得发酵周期延长至300 h左右,平均效价增长37.6%。该工艺提高了发酵水平,在实际生产中推广应用可以降低成本,提高生产效率。 相似文献
7.
利用链霉菌ST菌株发酵生产腐植酸。在蔗渣发酵培养基的基础上,采用一次回归正交试验,对腐植酸发酵过程中接种量(I)、通气量(搅拌次数,A)、温度(T)及时间(D)4个因素对腐植酸产量的影响情况进行分析。结果表明发酵时间的影响最为显著,接种量影响显著;所得到的回归方程有效且可信度高,回归方程为y=6.0356+0.0250I+0.0033A+0.0069T+0.2425D,其中各因素均与腐植酸产量呈正相关性。该回归方程为腐植酸生产过程链霉菌ST菌株发酵条件的控制提供了很好的指导作用。 相似文献
8.
补料—批式发酵生产青霉素G的最优控制策略比较 总被引:1,自引:0,他引:1
补料-批式发酵通常有两种最优控制策略:以底物的流加速率和流加底浓度作为控制和调节变量。本文以补料-批式发酵生产青霉素G为模型体系,运用敏感性分析模型比较了种最优控制策略。从系统的易控性、稳定性和最优解的可得性角度研究指出:以流加底物浓度作为最优控制和调节变量具有显著的优越性。 相似文献
9.
10.
11.
红花油制取共轭亚油酸的研究 总被引:2,自引:0,他引:2
以新疆克拉玛依厂的红花油为原料,以丙三醇为溶剂,在KOH的碱性催化作用下,将红花油先转化成亚油酸钾;再利用异构化反应制得浅黄色的共轭亚油酸产品。对产品进行了薄层层析法和紫外分光光度法定性分析,并定量分析了红花油异构化反应的程度。本研究对红花油的深加工将起到很好的推动作用。 相似文献
12.
13.
产朊假丝酵母流加发酵法生产谷胱甘肽 总被引:8,自引:0,他引:8
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%. 相似文献
14.
Hamza Alaşalvar Hakan Erinç Fatma Salur Ayşe Özbey 《Journal of the American Oil Chemists' Society》2019,96(7):839-846
Conjugated linoleic acid (CLA) is commercially produced by alkali isomerization of linoleic acid (LNA). However, this method constitutes a relatively high content of undesirable CLA isomers. In present study, microwave-assisted and ultrasound-assisted alkali isomerization techniques were applied for production of CLA as an alternative to traditional alkali isomerization. This study was aimed to evaluate the isomerization degree of LNA, by using various process conditions such as microwave power, ultrasound amplitude, and their reaction times. The best conditions for LNA isomerization were a microwave power of 700 W and a reaction time of 6 h for microwave-assisted alkali isomerization and an ultrasound amplitude of 100% and a reaction time of 6 h for ultrasound-assisted alkali isomerization. Under determined conditions, microwave-assisted alkali isomerization (97.21%) resulted in a higher isomerization degree compared to ultrasound-assisted alkali isomerization (76.98%) while the content of undesirable CLA isomers in ultrasound-assisted alkali isomerization (0.62%) was lower than that of microwave-assisted alkali isomerization (1.87%). This study showed that application of the both techniques resulted in equal amounts of desirable CLA isomers. The content of desirable CLA isomers was 47.09% cis-9, trans-11 and 48.25% trans-10, cis-12 for microwave-assisted alkali isomerization and 36.34% cis-9, trans-11 and 40.02% trans-10, cis-12 for ultrasound-assisted alkali isomerization. 相似文献
15.
以亚油酸乙酯为底物,开发了一条利用豆粕为直接催化剂,在线偶联脂氧酶提取的高效合成氢过氧化物的方法。对影响氢过氧化亚油酸乙酯产率的各因素:温度、pH以及催化剂和底物用量等进行了研究。豆粕催化氧化亚油酸乙酯的最佳反应条件为:1.5 g亚油酸乙酯,1.5 g豆粕,0.45 mL乙醇溶于7.5 mL pH=6的磷酸盐缓冲液,反应温度15℃,反应时间2 h,在该条件下产率达55%。该法不仅省去提取、纯化等工序,而且提高了LOX反应的催化效率和产率,使生物转化过程更接近于工业化生产的需要。 相似文献
16.
Khin Nyein Ei San Ye Fan Yun Fang Yongmei Xia Lin Ma 《Journal of the American Oil Chemists' Society》2020,97(9):1021-1028
Conjugated linoleic acid (CLA) exhibits beneficial biological activities but possesses poor natural abundance, which is usually obtained by alkali isomerization of linoleic acid (LNA). The one-pot alkali isomerization consists two reactions, firstly saponifying LNA and then isomerizing linoleate. This current process has been limited by two drawbacks, the overconsumption of both alkali and solvent, as well as the weak mass/heat transfer of the viscous paste of reaction mixture that limits the synthesis scale. The present study alternated the reaction pathway with a soap-free preferential esterification pathway, that is, firstly employing slight NaOH to induce the esterification of LNA and diol (the reaction solvent), then conducting alkali isomerization of the intermediate alkyl linoleate instead of sodium linoleate. In this developed one-pot procedure, a CLA yield of 90% and the selectivity of the desired isomers (“c9, t11” and “t10, c12” CLA) of 82.4% were obtained; and it reduced the consumption of NaOH and the solvent by 60% and 25% comparing to the current soap pathway, respectively; Yet the result is comparative to that obtained with assistant of microwave/ultrasound in even longer reaction time. In this way, the two drawbacks can be overcome and the green characteristics of the current process was well kept. 相似文献
17.
Conjugated linoleic acid(CLA)is a kind of fatty acid with physiological activities and potential appli-cation prospect ,A synthesis method of conjugated linoleic acid and a purification technology were studied .CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material,The purity of CLA and total recovery of the product was more than 95% and 48%,respectively,The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC)linked to mass spectrometry(MS) and Fourier transform infrared spectroscopy(FTIR),The total amount of the two main isomers (9cis,11trans-and 10trans,12cis-CLA) determined by GC was more than 90% of the product. 相似文献
18.
19.
丙酮酸是一种重要的有机酸 ,广泛应用于制药、日化、农用化学品和食品等工业中。相对于化工法生产的丙酮酸而言 ,发酵法生产的丙酮酸具有低成本、高质量等优势。考虑到球拟酵母属的多重维生素营养缺陷型菌株是目前发酵法生产中最常用和最具竞争力的生产菌株 ,因此重点介绍了发酵法生产丙酮酸在菌种、发酵条件优化等方面的研究进展 ,并给出了发酵法将来可能的发展方向。 相似文献