School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore, 632 014, Tamil Nadu, India.
Department of Agricultural Biotechnology (Metabolic Engineering Division), National Institute of Agricultural Sciences, Rural Development Administration, Jeonju, Republic of Korea.
Sci Rep. 2018 May 3;8(1):6972. doi: 10.1038/s41598-018-25417-5.
The unicellular marine alga Dunaliella salina is a most interesting green cell factory for the production of carotenes and lipids under extreme environment conditions. However, the culture conditions and their productivity are the major challenges faced by researchers which still need to be addressed. In this study, we investigated the effect of bicarbonate amendment on biomass, photosynthetic activity, biochemical constituents, nutrient uptake and antioxidant response of D. salina during macronutrient deficit conditions (N, P and S). Under nutrient deficit conditions, addition of sodium bicarbonate (100 mM) significantly increased the biomass, carotenoids including β-carotene and lutein, lipid, and fatty acid content with concurrent enhancement of the activities of nutrient assimilatory and carbonic anhydrase enzymes. Maximum accumulation of carotenoid especially β-carotene (192.8 ± 2.11 µg/100 mg) and lipids (53.9%) was observed on addition of bicarbonate during nitrate deficiency compared to phosphate and sulphate deficiency. Supplementation of bicarbonate reduced the oxidative stress caused by ROS, lowered lipid peroxidation damage and improved the activities of antioxidant enzymes (SOD, CAT and APX) in D. salina cultures under nutrient stress.
单细胞海洋藻类盐生杜氏藻是一种在极端环境条件下生产类胡萝卜素和脂类的非常有趣的绿色细胞工厂。然而，培养条件及其生产力是研究人员面临的主要挑战，仍需要解决。在这项研究中，我们研究了碳酸氢盐添加对杜氏盐藻在大量营养物质缺乏条件下（N、P 和 S）的生物量、光合作用活性、生物化学成分、养分吸收和抗氧化反应的影响。在营养缺乏条件下，添加碳酸氢钠（100mM）可显著提高生物量、类胡萝卜素（包括β-胡萝卜素和叶黄素）、脂类和脂肪酸含量，并同时增强养分同化和碳酸酐酶的活性。与缺磷和缺硫相比，在缺硝酸盐的情况下添加碳酸氢盐可使类胡萝卜素（尤其是β-胡萝卜素（192.8±2.11μg/100mg）和脂类（53.9%）的积累达到最大值。碳酸氢盐的补充减少了由 ROS 引起的氧化应激，降低了脂质过氧化损伤，并提高了在营养胁迫下杜氏盐藻培养物中抗氧化酶（SOD、CAT 和 APX）的活性。
