GENERATION OF LIPID-RICH MUTANTS AND CHARACTERIZATIONS IN GREEN ALGA MICROALGA DUNALIELLA TERTIOLECTA

Abstract

Dunaliella tertiolecta was used to generate lipid-rich mutants via insertional mutagenesis. D9 mutant was generated with a lipid yield that is 2 to 4-fold higher than that of wild type. Nile red method for rapid quantification of TAG was optimized for mutant screening. To characterize mutants and perform genetic manipulation, in-house transcriptome database was constructed based on high-throughput sequencing data using high performance computing in a petascale data center. The pipeline to analyze RNA-Seq data for comparative transcriptome analysis was developed. Thus the regulatory mechanism of D9 mutant was characterized. To address the dilemma of separation of cell growth phase and lipid accumulation phase, target screening using fluorescence-activated cell sorting was performed. D. tertiolecta mutant (G11_7) with TAG accumulation from the exponential growth phase (TAEP) was generated. It was discovered that refilling of acetyl-CoA pool through branched-chain amino acid catabolism contributed to six-fold TAEP with marginal compromise (4%) on growth.