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Abstract：
Chromochloris zofingiensis, a unicellular green alga, is a potential source of natural carotenoids. In this study, the mutant LUT-4 was acquired from the chemical mutagenesis pool of C. zofingiensis strain. The biomass yield and lutein content of LUT-4 reached 9.23 g·L-1, and 0.209% of dry weight (DW) on Day 3, which was 49.4%, and 33% higher than that of wild-type (WT), respectively. The biomass yields of LUT-4 under 100, 300, and 500 µmol/m2/s reached 8.4 g·L-1, 7.75 g·L-1, and 6.6 g·L-1, which was 10.4%, 21%, and 29.6% lower compared with the control, respectively. Under mixotrophic conditions, the lutein yields were significantly higher than that obtained in the control. The light intensity of 300 µmol/m2/s was optimal for lutein biosynthesis and the content of lutein reached 0.294% of DW on Day 3, which was 40.7% more than that of the control. When LUT-4 was grown under 300 µmol/m2/s, a significant increase in expression of genes implicated in lutein biosynthesis, including phytoene synthase (PSY), phytoene desaturase (PDS), and lycopene epsilon cyclase (LCYe) was observed. The changes in biochemical composition, Ace-CoA, pyruvate, isopentenyl pyrophosphate (IPP), and geranylgeranyl diphosphate (GGPP) contents during lutein biosynthesis were caused by utilization of organic carbon. It was thereby concluded that 300 µmol/m2/s was the optimal culture light intensity for the mutant LUT-4 to synthesize lutein. The results would be helpful for the large-scale production of lutein.
摘要：
嗜铬动物，一种单细胞绿藻，是天然类胡萝卜素的潜在来源。在这项研究中,突变体LUT-4是从C.zofingiensis菌株的化学诱变库中获得的。在第3天，LUT-4的生物量产量和叶黄素含量达到9.23g·L-1，干重（DW）的0.209％，为49.4％，比野生型(WT)高33%，分别。LUT-4在100、300和500µmol/m2/s下的生物量产量分别达到8.4g·L-1、7.75g·L-1和6.6g·L-1，分别为10.4％，21%,比对照组低29.6%，分别。在混合营养条件下，叶黄素的产量明显高于对照组。300µmol/m2/s的光强度对于叶黄素生物合成是最佳的，在第3天，叶黄素的含量达到DW的0.294％，比对照高40.7％。当LUT-4在300μmol/m2/s下生长时，与叶黄素生物合成有关的基因表达显着增加，包括八烯合成酶（PSY），八烯去饱和酶（PDS），并观察到番茄红素ε环化酶（LCHe）。生化成分的变化，Ace-CoA,丙酮酸,异戊烯焦磷酸(IPP),叶黄素生物合成过程中的香叶基香叶基二磷酸（G3GPP）含量是由有机碳的利用引起的。由此得出结论，300μmol/m2/s是突变体LUT-4合成叶黄素的最佳培养光强度。该结果将有助于叶黄素的大规模生产。
