Enhanced triacylglycerol production in chlorella vulgaris by flux balance analysis on metabolic network

Abstract

Triacylglycerol (TAG) is a type of lipid that can be produced by a microalga called Chlorella vulgaris, which is a promising source of biodiesel. However, there is a lack of research and models explaining how to directly produce this lipid. To address this, we propose using linear minimization of metabolic adjustment (LMOMA), which predicts gene manipulation effects based on Flux Balance Analysis (FBA), to enhance TAG production. We conducted single-gene deletion experiments on the genome-scale metabolic model of C. vulgaris UTEX 395 (iCZ843) under different growth conditions: heterotrophy, photoautotrophy, and mixotrophy conditions. We found that the TAG production increased by 5 and 8 times in heterotrophy after deleting genes ‘genemark_Scaffold_1220-abinit-gene-0.13’ and ‘genemark_Scaffold_1016-abinit-gene-0.16’, respectively. Moreover, in photoautotrophic, after the deletion of ‘maker_Scaffold_332-augustus-gene-0.46’ gene, we found that the TAG productions were increased at 7 times. In mixotrophic, the TAG production was increased at 5 times after the deletion of 'maker_Scaffold_33-augustus-gene-0.119'. Moreover, even if there is limited information about fatty acid β-oxidation in Chlorella vulgaris, our study suggests that manipulating this process could be a valuable strategy for enhancing TAG production for this species. Understanding and manipulating the fatty acid β-oxidation pathway could contribute to the development of high TAG strains for various applications, including biofuel, nutrition, and eco-friendly solutions.