初级代谢产物和有性生殖促进剂对番茄红素发酵的影响

考察几种初级代谢中间产物对三孢布拉霉发酵生产番茄红素的影响,以及卵磷脂对三孢布拉霉正负菌接合孢子及发酵的影响。结果表明：发酵24h分别添加2．0％的柠檬酸和2．0％的三孢酸,番茄红素的产量分别达到0．99g／L和1．26g/L,比对照分别提高39．43％和32．63％;卵磷脂的添加能促进三孢布拉霉两性接合孢子的形成,进而促进番茄红素的合成,当大豆卵磷脂的添加量为0．3％时,番茄红素的产量为1．58g/L,比对照提高56．44％。     

三孢布拉霉生产番茄红素研究进展

番茄红素是一种能够预防某些癌症,心血管疾病等慢性病的重要类胡萝卜素。三孢布拉霉是产生番茄红素的主要微生物之一。对番茄红素的理化性质,三孢布拉霉的生物学特性,高产菌株的选育,培养基及工艺的优化,番茄红素的提取,市场状况及开发前景等进行了综述。     

微生物发酵产生的番茄红素的分离纯化

研究了三孢布拉霉(Blakeslea trispora)发酵产生的番茄红素的分离纯化方法。与植物源的番茄红素相比,真菌发酵产物中含有更多的油脂成分,且提取物中含有的一些同分异构体与产物性质类似而不易分离。实验采用溶剂抽提、大孔吸附树脂吸附法纯化以及结晶的方法可获得番茄红素晶体,纯度达70.9%,收率为64.6%。产品经重结晶后可获得纯度90%以上的番茄红素,经红外、核磁、质谱等证实与植物来源的番茄红素相一致。     

三孢布拉霉发酵生产番茄红素的提取工艺及残留溶剂去除

用超声波皂化法从三孢布拉霉(Blakeslea trispora)发酵菌丝中提取番茄红素,对皂化条件、超声处理时间、提取温度和时间进行优化,得到番茄红素含量大于0.5%的番茄红素油树脂,总提取率达92.9%。提出溶剂提取与SC-CO2去除溶剂的技术路线,使番茄红素粗提物的溶剂残留符合标准。     

代谢途径酶活促进剂对番茄红素发酵的影响

考察了几种代谢途径中关键酶活促进剂对番茄红素发酵的影响。通过添加代谢途径中HMg-CoA还原酶与MVA激酶酶活促进剂,提高类胡萝卜素前体物质的生物合成,从而促进三孢布拉霉菌合成番茄红素的能力。实验结果表明,发酵24 h分别加入质量分数0.05%的某醇及其代谢产物A、1 mg/L的青霉素和质量分数0.1%β-紫罗酮,番茄红素的产量分别提高了31%,32%及35%,最大产量达到1.54 g/L。     

三孢布拉霉发酵生产β-胡萝卜素工艺研究

研究了应用三孢布拉霉生产β-胡萝卜素的发酵工艺。在种子培养阶段,采用正负菌孢子混合培养的方法,并对发酵条件进行了优化,得到了一个稳定、简便的工艺条件,β-胡萝卜素产量达到1.39g/L。     

crgA调控三孢布拉霉合成类胡萝卜素

【目的】探究crgA基因在三孢布拉霉合成类胡萝卜素过程中的调控作用。【方法】克隆三孢布拉霉crgA基因并利用split-marker策略敲除该基因;在表型特征、关键酶基因转录水平、类胡萝卜素合成水平等方面将基因敲除株与野生株进行比较分析。【结果】与野生型菌株相比,crgA基因敲除菌产孢能力明显下降,而类胡萝卜素合成途径中的关键酶基因转录水平明显提高,在发酵120h后β-胡萝卜素的积累量提高了31.2%。将crgA基因重新导入到敲除菌后,该菌的性状恢复至野生型。【结论】crgA基因调控三孢布拉霉的生长和产孢能力,并通过调控类胡萝卜素关键酶基因表达来调控类胡萝卜素的合成,是一个负调控因子。     

添加氧载体及表面活性剂对番茄红素发酵的影响*

通过添加氧载体(正十二烷、正己烷、过氧化氢),有效改善发酵体系中的氧传递速率,从而促进了三孢布拉氏霉菌合成番茄红素的能力。实验结果表明,在第0d加入1.0%的正己烷、正十二烷时番茄红素的生成量分别提高了25.32%、72.84%,在第1d,添加50μL/100mL过氧化氢时番茄红素的生成量提高了40.35%,在加入正十二烷的同时,再加入表面活性剂Triton-x100,Tween20,Tween80,Span-20等,可使番茄红素的产量最多提高114.83%。     

发酵法生产制备番茄红素的工艺研究

番茄红素是一种类胡萝卜素，存在于多种果蔬中，具有较好的抗氧化、抗衰老、提高免疫力等功能，被广泛应用于医药、食品、化妆品等领域。然而，传统的提取方法番茄红素产量低、成本高且受制于原料来源，化学合成法存在安全隐患。微生物发酵法因具有工艺简单、生产效率高、生物活性与天然植物提取物一致等优点，逐渐受到关注。基于此，以番茄红素产量为响应值，在单因素实验的基础上利用响应面法优化代谢控制条件，考察正负菌株接种比例、代谢流抑制剂和外源性植物油对番茄红素产量的影响。结果表明，最优条件为三孢布拉氏霉菌负正菌株接种比例6∶1，番茄红素环化酶抑制剂2,6-二甲基吡啶添加量0.09 g·L-1，以3.57 g·L-1大豆油为外源性植物油辅助发酵，在该最优条件下发酵液中的番茄红素产量达1.51 g·L-1，菌体生物量51 g·L-1。研究结果显著提高了发酵菌体生物量，促进了番茄红素的生物合成转化率，为番茄红素的工业化生产提供了理论基础。     

添加氧载体及表面活性剂对番茄红素发酵的影响

通过添加氧载体（正十二烷、正己烷、过氧化氰）,有效改善发酵体系中的氧传递速率,从而促进了三孢布拉氏霉菌合成番茄红素的能力。实验结果表明,在第0d加入1．0％的正已烷、正十二烷时番茄红素的生成量分别提高了25．32％、72．84％,在第1d,添加50μL/100mL过氧化氢时番茄红素的生成量提高了40．35％,在加入正十二烷的同时,再加入表面活性剂Trilorl—x100,Tween20,Tween80,Span-20等,可使番茄红素的产量最多提高114．83％．     

Use of metabolic stimulators and inhibitors for enhanced production of beta-carotene and lycopene by Blakeslea trispora NRRL 2895 and 2896

This work investigates the potential of metabolic stimulators, firstly to enhance the production of beta-carotene, and later use of inhibitors of lycopene cyclase so as to accumulate lycopene in the fermentation medium. Various non-ionic surfactants, natural oils, stimulators such as amino-acids, tricarboxylic acid cycle (TCA) intermediates, vitamin A and antibiotics were investigated for improved production of beta-carotene using the zygomycete fungus Blakeslea trispora. Span 20 at 0.2% increased the beta-carotene production from 139 mg/l to 318 mg/l. Examination of the mycelial morphology of the B. trispora with span 20 showed a shorter mycelial length, which allowed a well-dispersed growth of B. trispora. Supplementation of the medium with 1000 ppm vitamin A acetate gave highest concentration of beta-carotene (830+/-6 mg/l). Several chemical inhibitors such as imidazole, pyridine, triethylamine, piperidine, and nicotinic acid were then evaluated to block the biosynthesis at lycopene. Piperidine at 500 ppm gave a 7.76-fold improvement, and produced high titers of lycopene (775+/-5 mg/l) in a medium supplemented with vitamin A acetate.     

Effect of high pressure on the carotenoid content of Blakeslea trispora Thaxter mycelium]

High hydrostatic pressure was shown to decrease the content of beta- and lambda-carotenes in the mycelium of Blakeslea trispora, but to increase the production of lycopene, neurosporene and phytoene.     

Improved lycopene production by Blakeslea trispora with isopentenyl compounds and metabolic precursors

The highest lycopene production in mated cultures of Blakeslea trispora was 578?mg/l by adding 42?mg geraniol/l to the medium after 48?h of growth. The control gave 317?mg/l. Adding isopentenyl alcohol at 40?mg/l, mevalonic acid at 17.5?mg/l or dimethyl allyl alcohol at 150?mg, each after 36?h growth, gave lycopene yields 62, 45 and 47%, respectively, higher than the control.     

Zygote formation in Blakeslea trispora: morphological peculiarities and relationship with carotenoid synthesis

Changes associated with zygospore formation in the mucorous fungus Blakeslea trispora were studied. Zygospores are dormant cells with thickened cell walls and large central lipid vacuoles containing large amounts of lycopene. We established for the first time that B. trispora gametangia of different sexes differ in their carotenoid content and revealed that zygote formation involves a novel structure that consists of densely intertwined hyphae. Using inhibitory analysis (blocking beta-carotene synthesis with diphenylamine and 2-amino-6-methylpyridine), we showed that suppression of carotene production results in the inhibition of zygote formation. Hence, we established a manifest dependence of zygote formation on beta-carotene synthesis.