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%。     

添加氧载体提高泰乐菌素发酵的得率

通过添加氧载体（如正十二烷、全氟化碳等）,提高了发酵系统中的氧传递速度,从而促进了泰乐菌素的生物合成。当加入５％的正十二烷或全氟化碳,泰乐菌素的生成量分别提高１４％和８％;在加入正十二烷和全氟化碳的同时,再加入载体Ａｉｄ—ＰｌｕｓＭＬ—５０Ｄ,可使泰乐菌素的生成量分别提高１９％和２０％。     

添加氧载体提高泰乐菌素发酵的得率*

通过添加氧载体（如正十二烷、全氟化碳等）,提高了发酵系统中的氧传递速度,从而促进了泰乐菌素的生物合成。当加入５％的正十二烷或全氟化碳,泰乐菌素的生成量分别提高１４％和８％;在加入正十二烷和全氟化碳的同时,再加入载体Ａｉｄ—ＰｌｕｓＭＬ—５０Ｄ,可使泰乐菌素的生成量分别提高１９％和２０％。     

液态烷烃氧载体对粘红酵母发酵产番茄红素的影响

研究正己烷、正十二烷、正十六烷3种液态烷烃作为氧载体对粘红酵母生长和番茄红素合成的影响,发现氧载体不仅使菌体生物量提高,同时使单位细胞的番茄红素产率增大,从而提高粘红酵母合成番茄红素的能力。3种液态烷烃中正十二烷作为氧载体效果较好,试验结果表明,在发酵第0 h时添加4%的正十二烷,细胞生物量达到16.49 g/L,番茄红素合成量达到42.32 mg/L分别比对照组提高了26.2%和50.17%。     

氧载体对L-天冬酰胺酶发酵过程影响的研究

以抗癌药物L－天冬酰胺酶生产为应用背景,针对发酵过程中存在严重耗氧问题,研究了氧载体对发酵过程的影响。通过对几种氧载体的筛选,认为正十二烷最适合于该发酵过程。随后以产物L－天冬酰胺酶活性、菌体浓度以及溶氧水平为主要指标,考察了氧载体在发酵过程中的作用．实验表明,发酵基质中5％正十二烷的添加量为最佳浓度,这种氧载体的加入,明显地提高了发酵介质中的溶氧水平,改善了供氧条件,增加了菌体浓度,提高了L－天冬酰胺酶发酵水平,在优化条件下,可使发酵液最终酶活提高21％左右。     

正十二烷强化氧传递促进法夫酵母虾青素的合成

对虾青素的氧载体强化氧传递双液相发酵进行了研究。实验结果表明,添加正十二烷(作为氧载体)可提高法夫酵母发酵时的溶氧水平,促进虾青素的合成:添加正十二烷 0.5-1.0%(w/v),虾青素产量随正十二烷添加量逐步提高,最高时达到3.0mg/L,对照组虾青素产率为2.15mg/L;当正十二烷浓度大于2%时,对虾青素的合成表现出明显抑制作用;而正十二烷的添加对细胞的干重没有表现出促进作用。因此虾青素产量的提高是单位质量细胞的虾青素合成效率提高的结果。罐上实验结果表明,发酵开始后的12-24 h时段的溶氧水平对于虾青素的整个合成周期的合成活性至关重要,为发酵供氧进行分段控制提供了依据。根据法夫酵母虾青素合成活性与细胞呼吸活性之间的关系,推测法夫酵母合成虾青素过程对氧的依赖可能与柠檬酸生产菌有着相似的机制。     

氧载体对小白链霉菌发酵生产ε-聚赖氨酸的影响

为了有效改善发酵体系中的溶氧水平,提高小白链霉菌Streptomyces albulus PD-1发酵生产ε-聚赖氨酸的能力,文中通过对氧载体的种类、最佳添加浓度以及添加时间进行筛选,最终确定在0 h添加0.5%(V/V)的正十二烷促进ε-聚赖氨酸生产效果最佳。在5 L发酵罐0 h添加0.5%的正十二烷进行批次补料发酵,ε-聚赖氨酸的产量和菌体干重分别可以达到(30.8±0.46)g/L和(33.8±0.29)g/L,较之对照组分别提高了31.6%和20.7%。ε-聚赖氨酸的产量和菌体干重的提高归因于0.5%正十二烷的添加促进发酵液中溶氧水平从23.8%提高到32%,同时发酵液中的一种主要副产物(聚二氨基丙酸)的含量下降31%。实验结果表明,正十二烷的添加可以提高S.albulus PD-1发酵液中的溶氧水平,抑制副产物的生成,促进ε-聚赖氨酸的合成。     

氧载体对L—天冬酰胺酶发酵过程影响的研究

以抗癌药物Ｌ天冬酰胺酶生产为应用背景,针对发酵过程中存在严重耗氧问题,研究了氧载体对发酵过程的影响。通过对几种氧载体的筛选,认为正十二烷最适合于该发酵过程。随后以产物Ｌ天冬酰胺酶活性、菌体浓度以及溶氧水平为主要指标,考察了氧载体在发酵过程中的作用,实验表明,发酵基质中５％正十二烷的添加量为最佳浓度,这种氧载体的加入,明显地提高了发酵介质中的溶氧水平,改善了供氧条件,增加了菌体浓度,提高了Ｌ天冬酰胺酶发酵水平,在优化条件下,可使发酵液最终酶活提高２１％左右     

氧载体发酵体系的氧传递特性及提高衣康酸产酸能力的研究

测定了不同氧载体的理化参数,研究了机械搅拌罐氧载体发酵体系中的氧载体的体积分数,搅拌转速和通风量对体积氧传递系数的影响,并推导出传质系数的关联式。实验表明,加入氧载体后,可提高发酵体系的ＫＬａ值３０－２００％,衣原酸发酵中加入氧载体正十二烷,可提高产酸１４％以上。     

双液相体系强化氧传递促进微生物油脂生产

文中通过添加氧载体正十二烷进行双液相发酵来提高发酵性丝孢酵母利用木薯淀粉水解液生产微生物油脂的产量。结果表明,在摇瓶发酵液中添加氧载体,能明显缓解发酵过程中的氧限制程度。在2 L发酵罐中添加1%正十二烷进行双液相高密度发酵,其发酵生物量和油脂产量分别达到101.2 g/L和50.28 g/L。气相色谱分析表明,添加了氧载体发酵的微生物油脂中含有更高的饱和脂肪酸含量。     

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。     

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％。     

溶氧对Blakeslea trispora分批发酵生产β-胡萝卜素的影响

在摇瓶和5 L发酵罐中研究了溶氧 (DO) 对Blakeslea trispora分批发酵生产β-胡萝卜素的影响,总结了5 L发酵罐中β-胡萝卜素发酵过程中溶氧的变化规律.结果表明,当500 mL摇瓶装液量为50 mL,转速为240 r/min条件下发酵生产β-胡萝卜素产量最大,达到3.416 g/L; 5 L发酵罐中,在搅拌转速为1 000 r/min,通气量为1.5 vvm的条件下,β-胡萝卜素的产量可达到3.712 g/L,略高于摇瓶,这可能是由于5 L发酵罐中的气液传递和混合状况好于摇瓶,促进了产物的合成.     

三孢布拉霉发酵产番茄红素的研究进展

番茄红素是一种重要的类胡萝卜素,在生物体中具有抗氧化、抗衰老、提高免疫力等生理功能。虽然已经有部分企业实现了番茄红素的工业化生产,但产量仍然是制约三孢布拉霉发酵生产番茄红素的重要因素。在本实验室研究的基础上,本文结合近年来国内外学者的研究成果,从遗传育种、发酵工艺优化、化学调控等方面综述了提高三孢布拉霉中番茄红素产量的研究进展,并展望了未来的研究方向。     

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.     

Media optimization for the production of beta-carotene by Blakeslea trispora: a statistical approach

Blakeslea trispora (+) MTCC, Blakeslea trispora NRRL 2895 (+), Blakeslea trispora NRRL 2896 (-) as well as intraspecific mating of both the strain types have been studied for optimum production of beta-carotene. Intraspecific mating of both the strain types increased the yield of beta-carotene to a considerable level (98+/-2mg/l) as compared to wild strains. Effect of different media components such as carbon, nitrogen, and sulphates, and that of process variables such as pH and inoculum size on beta-carotene production by Blakeslea trispora in shake flask culture was investigated. One factor at-a-time method was employed for the optimization of media components. Response surface methodology (RSM) was further used to determine the optimum values of process variables for maximum beta-carotene production. The fit of the quadratic model was found to be significant. A significant increase in beta-carotene production (139+/-1mg/l) was achieved using RSM.     

Effect of the ratio of (+) and (−) mating type of Blakeslea trispora on carotene production from cheese whey in submerged fermentation

The effect of the ratio of (+) and (?) mating type of Blakeslea trispora on carotene production from deproteinized hydrolysed whey in shake flask culture was investigated. Also, the inoculum ratio of the two mating types on the morphology of the microorganism and the relationship between morphological changes of the fungus and product formation were studied. The concentration of carotenes was significantly affected by the ratio of (+) and (?) mating type of B. trispora. A ratio of 1:10 up to 1:100 of (+) and (?) type was found to achieve the highest carotene yields. The optimum ratio of the (+) and (?) mating types for the maximum pigment production (175.0 mg/g dry biomass at 8 days of fermentation) was found to be 1:10. The carotene content in B. trispora consisted of β-carotene, γ-carotene, and lycopene. At the maximum concentration of carotenes the proportion of β-carotene, γ-carotene, and lycopene (as percent of total carotenes) was 80, 12, and 8%, respectively. B.trispora growing in submerged fermentation is able to develop complex morphologies which have been classified into three major groups: freely dispersed hyphae, clumps and pellets. These parameters are strongly influence the production of carotenes.     

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。     

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。     

Lycopene production from synthetic medium by <Emphasis Type="Italic">Blakeslea trispora</Emphasis> NRRL 2895 (+) and 2896 (−) in a stirred-tank fermenter

The dissolved oxygen tension of 20% of air saturation, pH-shift from 4.0 to 5.5 on day 3, and a moderate shear stress (calculated as an impeller tip speed, V_\texttip = 0. 9 2 6- 2. 1 6 1  \textm/\texts V_{\text{tip}} = 0. 9 2 6- 2. 1 6 1 \, {\text{m}}/{\text{s}} ) were identified to be the key factors in scaling-up the mated fermentation of Blakeslea trispora NRRL 2895 (+) and 2896 (−) for lycopene production from a shake flask to a stirred-tank fermenter. The maximal lycopene production of 183.3 mg/L was obtained in 7.5-L stirred-tank fermenter, and then the mated fermentation process was successfully step-wise scaled-up from 7.5- to 200-L stirred-tank fermenter. The comparability of the fermentation process was well controlled and the lycopene production was maintained during the process scale-up. Furthermore, with the integrated addition of 150 μmol/L abscisic acid on day 3, 0.5 g/L leucine and 0.1 g/L penicillin on day 4, the highest lycopene production of 270.3 mg/L was achieved in the mated fermentation of B. trispora in stirred-tank fermenter.