Saccharomyces cerevisiae和Yarrowia lipolytica对自由饱和脂肪酸的选择性吸收及胞内积累特性研究

Selective Uptake and Increased Accumulation of Free Saturated Fatty Acids by the Yeast Saccharomyces cerevisiae and Yarrowia lipolytica

利用产油微生物生产特殊功能、高附加值的脂肪酸,具有良好的开发利用前景。以酿酒酵母(S.cerevisiae)和解脂耶氏酵母(Y.lipolytica)为出发菌株,以链长C4-C18的单一自由饱和脂肪酸作为唯一碳源,探究了两类酵母吸收利用、积累脂肪酸情况及胞内脂肪酸组成情况。结果表明:当碳链长C≤10时不能被利用,而且抑制细胞的生长,特别是当碳链长C≤8时,细胞很快被杀死;当碳链长C=11时,对细胞的生长有一定的抑制作用,菌体长势缓慢;碳链长C≥12时,对细胞生长没有影响;脂肪酸利用速度,偶数C脂肪酸>奇数C脂肪酸;Nile red全细胞脂类染色显示,S.cerevisiae胞内脂质主要集中于胞内周边膜部位,Y.lipolytica主要以脂质体形式存在胞内,及少部分在胞内周边膜部位;GC/Mass脂类成分分析表明,菌株S.cerevisiae S228C BY4741-pox1和S.cerevisiae S228C BY4741-pox1,3可以积累培养基添加的相应脂肪酸,而其他供试菌积累的脂肪酸链长C≥16,没有检测到培养基含有相应的脂肪酸。这些结果为利用酵母生产特殊功能脂肪酸,及开发特色高附加值油脂提供了有意义的参考。

It has quite significance and broad application prospects to develop novel strategies to produce special functional fatty acids with high added value by oleaginous microorganisms. Two kinds of yeasts S.cerevisiae and Y. lipolytica were selected to test how to selective uptake and increased accumulation of free saturated fatty acids. The results shown that when C ≤10 carbon chain length,free saturated fatty acids couldn＇t be uptaked and utilized on the contrary to suppresses the growth of cell,especially C ≤ 8 cells were killed quickly; When C = 11,it had certain inhibitory effect on the growth of cells which leads to the weak growth of bacteria; When C ≥12,it had no impact on cell growth and cells grew well; Even C fatty acids was digested faster than the base C fatty acids; Lipid body could be visualized by fluorescence microscopy of cells stained with Nile red. No significant variations were observed in S.cerevisiae or its mutants grown on YNBD. Where only a few small LB were observed in Y. lipolytica grown on YNBD. After growth YNBF medium,Y. lipolytica strain contained several larger LB and a few smaller ones in cell; The experiment of GC / Mass analysis indicated that the most of fatty acids except long-chain fatty acid（C≥16） could be uptaked and accumulated by S.cerevisiae S228C BY4741-pox1 or S.cerevisiae S228C BY4741-pox1,3 from culture medium,however medium-chain fatty acid couldn＇t be accumulated by original S.cerevisiae S228C BY4741. Thus,yeast could uptake and accumulate saturated fatty acid based on different carbon chain length. The most of fatty acids except long-chain fatty acid（ C≥16） could be uptaked and accumulated by S.cerevisiae S228C BY4741-pox1 or S.cerevisiae S228C BY4741-pox1,3 mutants from culture medium. The most of fatty acids also could be uptaked by Y.lipolytica from culture medium in cell.