Enhanced biodiesel properties of Auxenochlorella sp. using chemical mutagenesis and Tralkoxydim

Abstract

ABSTRACT Mutagenesis in microbial strains might result in robust strains with enhanced biofuel properties. Besides that, oleaginous microalgae, Auxenochlorella sp. with enhanced biomass and lipid content, can be a strong candidate for biodiesel production. In this context, a chemical mutagen called ethyl methane sulfonate (EMS) was screened at different concentrations. Considering that a lower survival rate can result in a higher mutation rate, an EMS concentration of 0.25M with 13 mins exposure time was selected as the optimum mutation condition. An acetyl-coenzyme A carboxylase (ACCase) inhibitor herbicide, tralkoxydim, was used as a selective environment to choose the mutant strains. Using an ACCase inhibitor herbicide would maintain a more desirable mutant strain that had the enhanced characteristics of biodiesel. Multi-scale comparisons between selected mutant strains and a wild strain revealed that by the time there was a remarkable decrease of 12.6% in the lipid content of the wild strain under the addition of Tralkoxydim (34.8%) compared to 39.8% in wild type, the lipid contents of the mutant strains remained higher. A remarkable increase by 1.50-fold and 1.33-fold in biodiesel fuel properties for Tralkoxydim-treated strains emphasizes that the ACCase synthesis pathway for lipid production is influenced by the stress factor that reaches the European biodiesel standards.