发酵法生产长链二元酸研究进展

发酵法生产长链二元酸相对于化工法而言有着无可比拟的优势。本文综述了发酵法生产长链二元酸的微生物源、产酸机理、产酸条件和产物分离技术等方面的研究进展,并简要介绍了其工业应用前景。     

发酵法生产长链二元酸研究进展

发酵法生产长链二元酸相对于化工法而言有着无可比拟的优势。本文综述了发酵法生产长链二元酸的微生物源、产酸机理、产酸条件和产物分离技术等方面的研究进展 ,并简要介绍了其工业应用前景。     

N~ 离子注入热带假丝酵母对长链二元酸产量的影响

用热带假丝酵母（Ｃａｎｄｉｄａ ｔｒｏｐｉｃａｌｉｓ）ＳＣＢ４１２作为出发菌株,经能量５０ＫｅＶ、剂量１× １０~１１～５ ×１０~１５ ｉｏｎｓ／ｃｍ~２的Ｎ~＋离子注入诱变处理,以产生可遗传的诱变。 Ｎ~＋离子注入后,存活率与剂量呈指数衰减关系：ｌｏｇ（存活率％）＝ ８．２３－ ０．６０４ × ｌｏｇ（剂量）,在培养过程中可观察到酵母菌菌落和细胞形态均发生了变化。经筛选,获得了一株能够利用正十二烷烃发酵产生长链二元酸的高产菌热带假丝酵母ＳＣＢ６０９。在初始正十二烷烃浓度为１５％（ｖ／ｖ）下产酸量由４３．５ｇ／Ｌ上升到７３．２ｇ／Ｌ。比较两株菌发酵生长特性的差异,产酸过程有一定的变化。     

现代生物技术在二元酸发酵菌种改良中的应用

在分析微生物发酵生产二元酸的代谢机理和相关酶系的基础上 ,对基因工程、代谢调控等现代生物技术在长链二元酸发酵菌种改良中应用的最新进展进行了全面的综述 ,对如何将传统的微生物发酵与现代生物技术有机结合作了简要讨论。     

新兴的绿色化学工业──微生物发酵生产长链二元酸

微生物发酵生产长链二元酸是绿色化学生物合成中一个重要研究领域,它研究开发的成功和工业化生产,形成一个新兴的绿色化学工业。 长链二元酸（Ｌｏｎｇ ｃｈａｉｎ ｄｉｃａｒｂｏｘｙｌｉｃ ａｃｉｄｓ）,是指碳链中含有１０个以上碳原子的脂肪族二羧酸,包括饱和及不饱和二羧酸,它们是一系列精细化工产品,有着重要而广泛的用途,是化学工业中合成高级香料、高性能工程塑料、高档热熔胶、高温电介质、高级喷漆和涂料、耐寒性增塑剂、树脂、医药和农药等的重要原料。这些长链二元酸,自然界中不单独存在,大多数饱和长链二元酸,在化学…     

N+离子注入热带假丝酵母对长链二元酸产量的影响*

用热带假丝酵母（Ｃａｎｄｉｄａ ｔｒｏｐｉｃａｌｉｓ）ＳＣＢ４１２作为出发菌株,经能量５０ＫｅＶ、剂量１× １０^１１～５ ×１０^１５ ｉｏｎｓ／ｃｍ^２的Ｎ^＋离子注入诱变处理,以产生可遗传的诱变。 Ｎ^＋离子注入后,存活率与剂量呈指数衰减关系：ｌｏｇ（存活率％）＝ ８．２３－ ０．６０４ × ｌｏｇ（剂量）,在培养过程中可观察到酵母菌菌落和细胞形态均发生了变化。经筛选,获得了一株能够利用     

丙氨酸对热带假丝酵母NPcoN22长链二元酸发酵的调节

本文研究了丙氨酸对热带假丝酵母(Candida tropicalis)NPcoN22长链二元酸发酵的调节,并把它与尿素的调节作了比较。在蔗糖利用、烷烃利用、菌体生长、发酵液pH变化和十四烷一1,14一二羧酸积累诸方面以及在三羧酸循环、乙醛酸循环、过氧化氢酶等酶的活力方面,丙氨酸具有与尿素相同的调节作用。丙氨酸加尿素作为混合氮源或在正常发酵过程中补加尿素或丙氨酸,其调节效果与过量尿素或过量丙氨酸单独存在条件下的情况一样,说明尿素和丙氨酸的调节作用具有相加效应。发酵过程中菌体对丙氨酸的利用特点表明了丙氨酸是菌体生长的限制因子。Β一氧化的抑制剂——丙烯酸能显著提高十四烷一1,14-二羧酸的积累。     

烷烃对P450酶的诱导及二元酸发酵工艺改进

α、ω 长链二元酸 (Ｌｏｎｇ ｃｈａｉｎα ,ω ｄｉｃａｒｂｏｘｙｌｉｃａｃｉｄ ,ＤＣＡ)是一种重要的化工原料 ,是合成工程塑料、香料、耐寒性增塑剂、涂料、液晶等物质的重要原料。目前主要利用热带假丝酵母 (Ｃａｎｄｉｄａｔｒｏｐｌｉｃａｌｉｓ)转化烷烃生产[1,2 ] 。在以往发酵的过程中 ,通常在初始培养液中加入 5 %～10 %的烷烃。且有文献表明在发酵初期加入烷烃有利于产酸的提高。但我们的研究表明 ,在发酵初期加入烷烃也有其不利的一面 ,如高浓度的烷烃对于菌体的生长有一定的抑制作用。而且有实验表明 :适当提高细胞的培养液…     

长链二元酸的用途

１长链二元酸的用途 长链二元酸是一类有着重要和广泛工业用途的精细化工产品,是制造高级香料、高性能尼龙工程塑料、高档尼龙热熔胶、高温电介质、高级润滑油、高级油漆和涂料、耐寒性增塑剂、树脂、医药和农药的重要原料。１．１合成高级香料 十一碳至十八碳二元酸（ＤＣ１１－ＤＣ１８）可以合成具有不同香型的大环酮,见表１。 ＤＣ１５和ＤＣ１６,经过不同的合成路线,都可以合成环十五酮和麝香酮（即３－甲基环十五酮）。麝香酮是天然麝香中具有生理活性的主要有效成分之一,而天然麝香稀罕难得,由于保护野生动物,更是奇缺,合成…     

代谢工程改造大肠杆菌合成己二酸

己二酸是一种具有重要应用价值的二元羧酸,是合成尼龙-66的关键前体。目前,生物法生产己二酸存在生产周期长、生产效率低的问题。本研究选择一株野生型高产琥珀酸菌株大肠杆菌(Escherichia coli) FMME N-2为底盘细胞,首先通过引入逆己二酸降解途径的关键酶,成功构建了可合成0.34 g/L己二酸的E. coli JL00菌株;接着,对合成路径限速酶进行表达优化,使E. coli JL01菌株在摇瓶发酵条件下产量达到0.87 g/L;随后,通过敲除sucD基因、过表达acs基因和突变lpd基因的组合策略平衡己二酸合成前体的供应,优化菌株E. coli JL12己二酸产量进一步提升至1.51 g/L;最后,在5 L发酵罐上对己二酸发酵工艺进行优化。工程菌株经72 h分批补料发酵,己二酸的产量达到22.3 g/L,转化率为0.25 g/g,生产强度为0.31 g/(L·h),具备了一定的应用潜力。本研究可为包括己二酸在内的多种二元羧酸细胞工厂的构建提供理论依据和技术基础。     

代谢工程改造大肠杆菌合成丙二酸

丙二酸是一种重要的有机二元羧酸,其应用价值遍及化工、医药、食品等领域。本文以大肠杆菌为底盘细胞,过表达了ppc、aspC、panD、pa0132、yneI和pyc基因,成功构建了丙二酸合成重组菌株大肠杆菌BL21(TPP)。该菌株在摇瓶发酵条件下,丙二酸产量达到0.61 g/L。在5 L发酵罐水平,采用间歇补料的方式丙二酸的积累量达3.32 g/L。本研究应用了融合蛋白技术,将ppc和aspC、pa0132和yneI分别进行融合表达,构建了工程菌BL21(SCR)。在摇瓶发酵水平,该菌株丙二酸的积累量达到了0.83 g/L,较出发菌株BL21(TPP)提高了36%。在5 L发酵罐中,工程菌BL21(SCR)的丙二酸产量最高达5.61 g/L,较出发菌株BL21(TPP)提高了69%。本研究实现了丙二酸在大肠杆菌中的生物合成,为构建丙二酸合成的细胞工厂提供了理论依据和技术基础,同时也对其他二元羧酸的生物合成具有启发和指导意义。     

Sugarcane-pressmud as a novel substrate for production of citric acid by solid-state fermentation

Sugarcane-pressmud, a by-product of cane-sugar manufacture, was used as a substrate for production of citric acid by Aspergillus niger CFTRI 30, in a solid-state fermentation system. Of the 170 g of sugar supplied, 131 g were consumed, with a 79% yield of citric acid over 120 h. Potassium ferrocyanide improved the conversion to about 88% and lowered the fermentation time by 24 h. Enrichment with sugar and NH₄NO₃ was essential to improve productivity. About 174 g citric acid/kg dry sugarcane-pressmud were produced after 120 h in ferrocyanid-treated medium which initially contained 12.5% (w/w) effective sugar and 0.1% (w/w) NH₄NO₃. About 3% (w/w) of the original sugar present in the sugarcane-pressmud was non-utilizable. This is the first report on the potential of sugarcane-pressmud for citric acid production.V.S. Shankaranand and B.K. Lonsane are with the Fermentation Technology and Bioengineering Discipline, Central Food Technological Research Institute, Mysore-570 013, India     

四碳有机酸生物合成的代谢工程研究进展

四碳有机酸作为重要的平台化学品,广泛应用于食品、化工、农业、医药和生物材料等领域.与传统的石化法相比,利用微生物发酵生产四碳有机酸具有反应条件温和、过程绿色环保等优势,具有广泛的应用前景.文中总结了四碳有机酸的生物合成途径和代谢机制,着重讨论了天然菌株生产四碳有机酸以及基于菌种选育和代谢工程改造策略提高四碳有机酸合成能...     

Anaerobic fermentation for n-caproic acid production: A review

Anaerobic fermentation-based technologies are used for treating organic residues, and producing high value-added products, such as solvents, gases, and organic acids. Among several organic acids, n-caproic acid can be used as antimicrobial agent, additive in animal feed, flavor additive, and feedstock for chemical and biofuel industries. n-Caproic acid formation occurs through a carboxylic acid chain elongation process, which uses reverse β-oxidation of acetic and/or n-butyric acid, and ethanol or lactic acid as an electron donor. This review addresses important issues in commercial n-caproic acid production: metabolic pathways, kinetics and thermodynamics, substrates, reactors, inhibition of competing biological activities, pH, and acid extraction. Additionally, a mathematical model to describe the reverse β-oxidation kinetics was evaluated from existing literature. Current investigations show a wide range of n-caproic acid production rates (3.0–55.8 g/(L·d)), using different open cultures, fermentation conditions, and methods for inhibiting the methanogenesis. Clostridium kluyveri presence and a dominance of the Clostridium spp. were identified as determinant when ethanol was provided as electron donor. Continuous n-caproic acid extraction through pertraction is a promising technology, which combines selective extraction and enhanced production rates. However, confirming the industrial feasibility of this process requires further investigation.     

Coffee husk: an inexpensive substrate for production of citric acid by Aspergillus niger in a solid-state fermentation system

Aspergillus niger CFTRI 30 produced 1.3 g citric acid/10 g dry coffee husk in 72 h solid-state fermentation when the substrate was moistened with 0.075 M NaOH solution. Production was increased by 17% by adding a mixture of iron, copper and zinc to the medium but enrichment of the moist solid medium with (NH₄)₂SO₄, sucrose or any of four enzymes did not improve production. The production of about 1.5 g citric acid/10 g dry coffee husk at a conversion of 82% (based on sugar consumed) under standardized conditions demonstrates the commercial potential of using the husk in this way.The authors are with the Department of Microbiology and Bioengineering, Central Food Technological Research Institute, Mysore-570 013, India;     

以4-香豆酸为底物转化白藜芦醇大肠杆菌工程菌的构建

白藜芦醇具有多种生物活性,在食品、化妆品及生物制药中具有广阔的应用前景。利用合成生物学生产白藜芦醇是未来的发展趋势。将白藜芦醇合酶(resveratrol synthase,RS)和4-香豆酰-CoA连接酶(4-coumaric acid-CoA ligase,4CL)的编码基因整合到共表达载体pETDuet-1上成功构建了重组质粒pETDuet-rs-4cl,转化大肠杆菌BL21(DE3),在M9培养基中添加4-香豆酸,在诱导条件下培养,发酵液中白藜芦醇含量为8.6 mg/L。本研究在大肠杆菌中实现了白藜芦醇的转化,为微生物法生产白藜芦醇奠定了基础。     

Enhanced production of C5 dicarboxylic acids by aerobic-anaerobic shift in fermentation of engineered Escherichia coli

Synthetic biology provides a significant platform in creating novel pathways/organisms for producing useful compounds, while it remains a challenge to enhance the production efficiency. Recently we constructed a recombinant Escherichia coli for glutarate production using a synthetic α-ketoacid reduction pathway, in which α-ketoglutarate is reduced to 2-hydroxyglutarate then converted to glutarate. However, the production titer was low, which may be due to 1) oxygen-sensitive nature of 2-hydroxyglutaryl-CoA dehydratase (HgdABC) and 2) limited cell growth in anaerobic cultivation. Therefore, we developed an aerobic-anaerobic two-stage strategy by growing more cells aerobically, then shifting to anaerobic cultivation to ensure the functional HgdABC for glutarate biosynthesis. The two-stage cultivation resulted in higher production of glutarate and other two C5 dicarboxylic acids – glutaconate and 2-hydroxylglutarate than the original anaerobic process. Furthermore, we used an anaerobically-inducible nar promoter to improve the hgdABC expression responding to aerobic-anaerobic shift. Finally, the glutarate, glutaconate and 2-hydroxyglutarate titer was increased about 2, 5 and 3 times, reaching 11.6, 108.8 and 399.5 mg/L, respectively. The work demonstrated an effective strategy for ameliorating α-ketoacid reduction pathway to produce C5 dicarboxylic acids, as well as the potential of integration of bioprocess and metabolic engineering for enhancing chemicals production by an engineered microorganism.     

灵芝液态发酵胞内外多糖的研究进展

灵芝具有悠久的药用历史,其活性物质灵芝多糖具有广泛的药理活性,利用液态发酵技术获取灵芝多糖展现出独特优势。近年来,关于灵芝多糖液态发酵的研究报道越来越多,引起了研究者的广泛关注。本文从灵芝多糖的生物合成代谢及调控、液态发酵的培养基及工艺优化等方面对近期的研究结果进行总结,以期为灵芝液态发酵制备胞内外多糖及其产业化应用提供参考和依据。