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。