Chemical Mutagenesis of Microalgae Nannochloropsis sp. Using EMS (Ethyl Methanesulfonate)

Abstract

Microalgae ability to grow substantially in a short period of time has become a starting point in rapid biofuel production. To date, only certain microalgae species that produce large biomass, and has high fatty acid content can be turned into raw material in producing biofuel. One of the methods used in increasing microalgae biomass is the mutagenesis method. This mutagenesis research were conducted chemically by adding ethyl methanesulfonate (EMS) into microalgae individual cells. The results showed the highest density among three treatments (control, 0.1 M and 0.5 M) occurred at 0.5 M EMS treatment, with a number of 60.7±11.93 x 106 cells/mL on day 6 (stationery phase). Among the three treatments, the highest specific growth occurred at 0.1 M EMS treatment (µ= 0.52/day) on day 5 (logarithmic phase), and treatment on 0.5 M EMS has highest RNA/DNA ratio (0.55±0.46), while control has the lowest ratio (0.12±0.04). In dry biomass, the highest number stationery and death phase occurred in Nannochloropsis sp. cultivation with EMS concentration of 0.1 M (1.08±0.33 and 1.11±0.07 g/l). Fat content percentage in both phase occured in EMS concentration of 0.5 M (12.17±0.30% and 18.14±0.35%). Chromatography test revealed 22 compounds of saturated fatty acid and 3 compounds of unsaturated fatty acid. Methyl palmitate (C16:0) was the saturated fatty acid with the highest concentration in three cultivation treatments. Mono unsaturated fatty acid (MUFA) with a relatively high concentration is methyl palmitoleate in two cultivation treatments. The only poly unsaturated fatty acid detected was methyl linoleate (C18:2).