Electroporation-induced mutation and transcriptome analysis for high DHA production in Schizochytrium limacinum GCD2032

The development of the DHA industry requires continuous iterative upgrading of high-yield DHA-producing strains. In this study, a DHA high-producing strain named S. limacinum GCD2032 was screened through electroporation using zeocin as the selective agent and S. limacinum BCD as the wild strain. The production enhancement mechanism was elucidated through comparative transcriptome studies between S. limacinum GCD2032 and the wild strain. The fatty acid content, DHA content and DHA yield of S. limacinum GCD2032 were 3.51 %, 95.51 % and 71.67 % higher than those of S. limacinum BCD, respectively. Transcriptome analysis indicated that genes involved in the aerobic oxidation of glucose, the pentose phosphate pathway, the citric acid pyruvate cycle, and the PKS pathway for DHA production were all upregulated and genes involved in β-oxidation in peroxisomes were downregulated, resulting in the enhanced DHA content of S. limacinum GCD2032. This study provides an efficient iterative upgrading method and key candidate genes for DHA production in Schizochytrium. S. limacinum GCD2032 is a promising strain for further industrialization.