Center for Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Polar Research Institute of China, Shanghai 200136, China.
Mar Drugs. 2021 Sep 30;19(10):559. doi: 10.3390/md19100559.
Species of are well known for their remarkable ability to produce lipids intracellularly. However, during their lipid accumulation, reactive oxygen species (ROS) are generated inevitably as byproducts, which if in excess results in lipid peroxidation. To alleviate such ROS-induced damage, seven different natural antioxidants (ascorbic acid, α-tocopherol, tea extract, melatonin, mannitol, sesamol, and butylated hydroxytoluene) were evaluated for their effects on the lipid accumulation in sp. PKU#Mn4 using a fractional factorial design. Among the tested antioxidants, mannitol showed the best increment (44.98%) in total fatty acids concentration. However, the interaction effects of mannitol (1 g/L) and ascorbic acid (1 g/L) resulted in 2.26 ± 0.27 g/L and 1.45 ± 0.04 g/L of saturated and polyunsaturated fatty acids (SFA and PUFA), respectively, in batch fermentation. These concentrations were further increased to 7.68 ± 0.37 g/L (SFA) and 5.86 ± 0.03 g/L (PUFA) through fed-batch fermentation. Notably, the interaction effects yielded 103.7% and 49.6% increment in SFA and PUFA concentrations in batch fermentation. The possible mechanisms underlining those increments were an increased maximum growth rate of strain PKU#Mn4, alleviated ROS level, and the differential expression of lipid biosynthetic genes andupregulated catalase gene. This study provides an applicable strategy for improving the accumulation of SFA and PUFA in thraustochytrids by exogenous antioxidants and the underlying mechanisms.
属的物种以其在细胞内产生脂类的非凡能力而闻名。然而，在它们积累脂质的过程中，不可避免地会产生活性氧物种 (ROS)，如果过量，就会导致脂质过氧化。为了缓解这种由 ROS 引起的损伤，使用分阶析因设计评估了七种不同的天然抗氧化剂（抗坏血酸、α-生育酚、茶提取物、褪黑素、甘露醇、芝麻酚和叔丁基对苯二酚）对 PKU#Mn4 产油的影响。在测试的抗氧化剂中，甘露醇对总脂肪酸浓度的增加效果最好（增加了 44.98%）。然而，甘露醇（1 g/L）和抗坏血酸（1 g/L）的相互作用效应导致分批发酵中饱和脂肪酸（SFA）和多不饱和脂肪酸（PUFA）的浓度分别为 2.26 ± 0.27 g/L 和 1.45 ± 0.04 g/L。这些浓度通过补料分批发酵进一步增加到 7.68 ± 0.37 g/L（SFA）和 5.86 ± 0.03 g/L（PUFA）。值得注意的是，分批发酵中的相互作用效应使 SFA 和 PUFA 浓度分别增加了 103.7%和 49.6%。这些增加的可能机制是 PKU#Mn4 菌株的最大生长速率增加、ROS 水平降低以及脂质生物合成基因的差异表达和过氧化氢酶基因的上调。该研究为通过外源抗氧化剂和潜在机制提高厚壳贻贝中 SFA 和 PUFA 的积累提供了一种可行的策略。
