Tsai Yung-Yu, Ohashi Takao, Wu Chih-Chan, Bataa Dolgormaa, Misaki Ryo, Limtong Savitree, Fujiyama Kazuhito
International Center for Biotechnology, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
J Biosci Bioeng. 2019 Apr;127(4):430-440. doi: 10.1016/j.jbiosc.2018.09.005. Epub 2018 Oct 11.
The oil plants provide a sufficient source of renewable lipid production for alternative fuel and chemical supplies as an alternative to the depleting fossil source, but the environmental effect from these plants' cropping is a concern. The high oleic acid (OA; C18:1) content in plant-derived products provide advantages of multiple uses with improved oxidative stability and a wide range of applicable temperature. Here we used a promising lipid producer, the oleaginous yeast Rhodosporidium toruloides, to attempt to obtain an OA-enriched lipid. Saccharomyces cerevisiae OLE1 (ScOLE1) gene encodes Δ9 fatty acid desaturase (Δ9FAD), which is generally known to synthesize palmitoleic acid (POA; C16:1) and OA, but the functions of putative R. toruloides Δ9FAD gene are not well understood. In a complementary test, the RtΔ9FAD gene rescued the survival of an OA-deficient Scole1Δ mutant, and we introduced the RtΔ9FAD gene into R. toruloides strains for the production of OA-enriched lipid. Increasing lipid production was observed in ScOLE1 and genomic RtΔ9FAD gene-overexpressing R. toruloides strains. The ScOLE1 transformant output fivefold more OA content in total amount, with >70% of total lipid. Different enhancing effects from the protein coding sequence and genomic sequence of RtΔ9FAD genes were also observed. Overall, this study resulted in ScOLE1 and RtΔ9FAD gene overexpression in R. toruloides to obtain OA-enriched lipid as a candidate source of designed biodiesel and lipid-related chemicals.
油料作物为替代燃料和化学品供应提供了充足的可再生脂质生产来源，以替代日益枯竭的化石资源，但这些作物种植所带来的环境影响令人担忧。植物源产品中高含量的油酸（OA；C18:1）具有多种用途的优势，其氧化稳定性得到改善，适用温度范围广泛。在这里，我们使用了一种有前景的脂质生产者——产油酵母红冬孢酵母，试图获得富含OA的脂质。酿酒酵母OLE1（ScOLE1）基因编码Δ9脂肪酸去饱和酶（Δ9FAD），通常认为该酶可合成棕榈油酸（POA；C16:1）和OA，但推定的红冬孢酵母Δ9FAD基因的功能尚不清楚。在一项互补试验中，RtΔ9FAD基因挽救了OA缺陷型Scole1Δ突变体的存活，并且我们将RtΔ9FAD基因导入红冬孢酵母菌株以生产富含OA的脂质。在ScOLE1和基因组RtΔ9FAD基因过表达的红冬孢酵母菌株中观察到脂质产量增加。ScOLE1转化体的OA总量输出增加了五倍，占总脂质的70%以上。还观察到RtΔ9FAD基因的蛋白质编码序列和基因组序列具有不同的增强作用。总体而言，本研究通过在红冬孢酵母中过表达ScOLE1和RtΔ9FAD基因，获得了富含OA的脂质，作为设计生物柴油和脂质相关化学品的候选来源。
