OPTIMIZATION OF PALMITIC ACID PRODUCTION IN CHLOROIDIUM SP. UTEX 3007 AS A SUSTAINABLE SOURCE OF PALM OIL ALTERNATIVE

The increase in palm oil consumption and production has resulted in removing up to 90% of trees in some tropical forests. The green microalgae Chloroidium sp. UTEX 3007 can be an alternative sustainable source of palm oil due to its high palmitic acid content. The objective of this study was to generate a mutant Chloroidium population that is capable of producing and accumulating elevated levels of palmitic acid and to characterize the obtained populations’ lipid contents. The palmitic acid production optimization in Chloroidium sp. UTEX 3007 was conducted via a workflow of ultraviolet (UV) mutagenesis and sorting of high-lipid producing mutants with Fluorescence-Activated Cell Sorting (FACS). The mutants’ lipid composition for increased palmitic acid content was analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS). Four iterative rounds of mutagenesis combined with FACS resulted in four mutant populations with increased lipid contents. Analysis of the mutant populations extracted lipids by UHPLC-QToF-MS showed a significant increase in palmitic acid compared to the parental strain. The metabolomic analysis of the fourth-mutant population’s lipids showed higher palmitic acid and malonyl-CoA. The latter is a precursor building block for palmitic acid as well as an inhibitor of fatty acid oxidation. Triacylglycerol (TAG) neutral lipids were higher in R4. The increase of malonyl-CoA may explain higher TAG and palmitic acid in R4. Importantly, other morphological characteristics and growth rates of the mutant population were not significantly affected. The iterative rounds of UV combined with FACS resulted in mutant populations with higher palmitic content than the wild-type strain. Individual cells isolated from these mutant populations may be further analyzed for their lipidomics and genomic alterations to identify promising candidates for palm oil alternative production.