High value unsaturated fatty acids can be produced by de novo synthesis in microalgal cells, especially via heterotrophic cultivation. Unfortunately, the lipid accumulation of heterotrophic microalgae cannot be improved efficiently in conventional ways. Here we reported heterotrophic Tribonema minus, a promising resource for the production of palmitoleic acid which has increasing demands in health service for patients with metabolic syndrome, as whole-cell biocatalyst to develop a novel way of shifting low value exogenous saturated fatty acids to high value ones. Results showed that myristic acid is the best precursor for whole-cell catalysis; it elevated the lipid content of T. minus to 42.2%, the highest among the tried precursors. The influences of cultivation condition on the utilization of extrinsic myristic acid and lipid accumulation were also determined. Under the optimized condition, the lipid content reached as high as 48.9%. In addition, our findings showed that ~13.0% of C16:1 in T. minus is derived from extrinsic myristic acid, and 30.1% of metabolized precursor is converted into heterologous fatty acids. Thus, a feasible approach for both increasing the value of low value saturated fatty acid by bioconversion and enhancing the lipid accumulation in microalgae is proposed by supplementing extrinsic myristic acid.

中文翻译：

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使用微藻通过全细胞催化生产高价值不饱和脂肪酸：以 Tribonema minus 为例

高价值的不饱和脂肪酸可以通过微藻细胞中的从头合成产生，特别是通过异养培养。不幸的是，异养微藻的脂质积累不能以常规方式有效改善。在这里，我们报道了异养Tribonema minus，一种用于生产棕榈油酸的有前景的资源，它在代谢综合征患者的健康服务中的需求不断增加，作为全细胞生物催化剂，可以开发一种将低价值外源饱和脂肪酸转化为高价值的新方法那些。结果表明，肉豆蔻酸是全细胞催化的最佳前体；它提高了T. minus的脂质含量达42.2%，在试用前驱体中最高。还确定了培养条件对外源肉豆蔻酸利用和脂质积累的影响。在优化条件下，脂质含量高达48.9%。此外，我们的研究结果表明，T. minus中约 13.0% 的 C16:1来自外源肉豆蔻酸，30.1% 的代谢前体转化为异源脂肪酸。因此，通过补充外源性肉豆蔻酸，提出了一种既通过生物转化提高低值饱和脂肪酸价值又提高微藻脂质积累的可行方法。