Biosynthesis of Unsaturated Fatty Acids via Mortierella Isabellina Cultivated in a Medium Containing Butanol

IntroductionThe biosynthesis of unsaturated fatty acidshasattracted more attention in recent years. Forexample,linoleic and linolenic acids are importantmaterials for pharmaceutical and food industries.Besides,they can be used to synthesize paint,printing ink and surfactant,etc. A number ofmicroorganisms have been studied as potentialcommercial sources to produce unsaturated fattyacids[1] .Agricultural and industrial products,by-products,etc. have been employed in thecultivation of those orga…     

(Z)-N-(4-Decenoyl)homoserine lactone, a new quorum-sensing molecule, produced by endobacteria associated with Mortierella alpina A-178

N-Acylhomoserine lactones (AHLs) are the conserved quorum-sensing signal molecules in Gram-negative bacteria. (Z)-N-(4-Decenoyl)homoserine lactone (1), a new AHL, was isolated from the culture broth of the fungus Mortierella alpina A-178 harboring bacterial endosymbionts, called endobacteria. The structure and absolute configuration of 1 were elucidated by EI-MS, chemical synthesis, and chiral GC analysis. The compound induced the expression of a QS-regulated reporter gene in Agrobacterium tumefaciens NTL4, although its activity was lower than that of N-decanoylhomoserine lactone (6).     

深黄被孢霉催化转化十八醇合成不饱和脂肪酸

深黄被孢霉催化转化十八醇合成不饱和脂肪酸在优化转化条件下所得产物分析表明,干细胞中含油脂47.5%,蛋白质31.5%,碳水化合物28.9%.十八醇转化率为67.2%,油脂选择性为30.6%,产率20.6%.油脂中脂肪酸的选择性为:棕榈酸4.00%,棕榈油酸0.81%,硬脂酸0.95%,油酸20.75%,亚油酸1.95%,亚麻酸2.19%.催化转化条件下的研究表明,底物浓度越低,油脂和不饱和脂肪酸的选择性越好,当十八醇质量分数为0.5%时,油脂和不饱和脂肪酸的选择性达到最大值;培养基pH为中性时,获得了最大的油脂选择性和收率;33℃时醇转化率达最大值88%,23℃油脂产率达最大值9.7%.Mg²⁺对不饱和脂肪酸的生成有显著影响,当培养基中[Mg²⁺]=25mmol/L时,获得了最大的油脂选择性(25.7%)和产率(17.6%).     

深黄被孢霉催化转化脂肪醇合成不饱和脂肪酸的初步研究

The unsaturated fatty acids were biosynthesized by Mortierella isabellina grown on fatty alcohols (butanol, hexadecanol, octadecanol, etc) at 28 ℃ for 5 d and the fatty acid composition was analyzed by gas chromatography. The results showed that more lipid and higher content of the corresponding unsaturated fatty acids could be biosynthesized by the fungi grown on the long chain alcohols. Meanwhile, long chain alcohols were converted more quickly and had higher conversion. It suggests that long chain alcohols are more practical substrates.     

反应条件对深黄被孢霉催化转化十六醇合成不饱和脂肪酶的影响

 研究了深黄被孢霉催化转化十六醇合成不饱和脂肪酸过程中反应条件对底物转化率及产物选择性的影响．结果表明,亚油酸的选择性随十六醇与酵母膏比例（碳氮比）的增大而升高,亚麻酸的选择性随碳氮比的增大而降低,油脂的选择性和油脂的产率随碳氮比的变化规律相似．十六醇浓度为0．5％时,油脂的选择性、产率及醇的转化率最高,亚油酸和亚麻酸的选择性也最高．油脂的选择性和产率在pH＝7时较高,而醇的转化率随pH升高而降低,亚油酸和亚麻酸的选择性在pH＝6时分别达到最大值．油脂的选择性、产率和醇的转化率在23～28℃达到较高水平,亚油酸和亚麻酸的选择性在23℃达到最大值．油酸的选择性对油脂的选择性有重要影响,二者的变化规律相似．     

被孢霉菌丝体脂肪酸组成的气相色谱-质谱分析

采用气相色谱－质谱对采自云南白马雪山土壤中并经分离和发酵培养的被孢霉菌株SM96的菌丝体油脂中脂肪酸组成进行了定性分析和峰面积相对含量测定，共检测出30种脂肪酸，其中多不饱和脂肪酸含量为62．4％，主要为亚油酸、α－亚麻酸（ALA），还有少量的γ－亚麻酸、二十碳三烯酸、花生四烯酸和二十碳五烯酸（EPA）等，结果表明该菌株能产生EPA。     

深黄被孢霉生物转化十六醇合成油脂的研究

不饱和脂肪酸有重要的生理机能 ,寻找富含不饱和脂肪酸的新油源 ,以弥补动植物油源的不足已成为当前的研究热点 .高碳醇转化为高碳酸已有报道[1],但将其转化为不饱和脂肪酸的研究还少见报道 .利用产脂微生物合成不饱和脂肪酸是开发新油源的良好途径[2 ,3].本文用深黄被孢霉生物转化十六醇合成油脂 ,并分析了油脂中脂肪酸的组成 ,对转化条件也进行了初步研究 .1　实验部分将深黄被孢霉 (Ｍｏｒｔｉｅｒｅｌｌａｉｓａｂｅｌｌｉｎａ)于 2 8℃在种子培养液中活化 2 4ｈ ,然后接种于十六醇转化培养基上 ,于 2 8℃摇瓶发酵 96ｈ(摇瓶转速 1 50ｒ…