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%).

Converting Octadecanol to Unsaturated Fatty Acids Catalyzed by Mortierella Isbellina

Mortierella isabellina was found to be used to synthesize unsaturated fatty acids when the fungus was cultivated in a medium consisting of 2% octadecanol,1% yeast extract and Mg ²⁺ with concentration at 25 mmol/Lat 23 ℃ for120 h. The harvested dry cells contained 47.5% lipids, 28.9% carbohydrate and 31.5% protein. The results showed that the lipid selectivity was 30.6%, at a yield of 20.6%. The data also indicated the selectivity of fatty acids in the lipids, was palmatioleic(0.81%), oleic(20.75%), linoleic(1.95%), linolenic(2.19%) respectively. Lowering the concentration of substrates in the medium led to increasing selectivities of both lipids and unsaturated fatty acids synthesized by the fungus, and when mass fraction of octadecanol was 0.5%, the maximal selectivities of the corresponding fatty acid were obtained. Astudy of initial pHof the medium suggested that the maximal selectivity and yield of lipids were obtained at a pHvalue of 7. The octadecanol conversion reached a maximum(88%) when cultivated at 33 ℃, however, the lipid yield reached a maximum(9.7%) at 23 ℃. Mg ²⁺ was found to strongly influence the productivity of lipids and unsaturated fatty acids. For instance, a concentration of 25 mmol/Lof Mg ²⁺ in the culture broth may cause a maximal selectivity(25.7%) and yield(17.6%) of lipids.