Green renewable energy production from Myxosarcina sp.: media optimization and assessment of biodiesel fuel properties

Renewable energy resources, like biomass from plants and algae, have gained more interest for biodiesel production as an energy source to reduce the consumption of fossil fuels and elevated global warming. In this study, Myxosarcina sp., a unicellular cyanobacterium, was evaluated for higher biomass and lipid production via the supplementation of sugar industrial waste (SIW) and sodium chloride (NaCl), and medium optimization with response surface methodology (RSM) for biodiesel production. The outcome of the findings was that greater biomass and lipid productivities of 28.5 +/- 2.4 (1.2 fold) and 3.4 +/- 0.2 (1.3 fold) mg L-1 per day were observed in BG-11 medium supplemented with SIW when compared with the control (24 +/- 1 and 2.6 +/- 0.4 mg L-1 per day). However, a higher lipid content 20.6 +/- 1.8% (1.5 fold) was achieved with RSM optimized medium, including NaCl at 0.8 M, SIW at 2 mL L-1, sodium nitrate (NaNO3) at 2.5 g L-1 and magnesium sulphate (MgSO4) at 0.075 g L-1, than in the control (13.6 +/- 1.4%). Fatty acid characterization by GC-MS analysis revealed that Myxosarcina sp. yielded 39 +/- 5.3% of saturated fatty acids (SFA) and 61 +/- 5.3% of monounsaturated fatty acid (MUFA) and its biodiesel fuel properties, evaluated using empirical equations, showed that almost all the properties calculated were in compliance with the national and international biodiesel standards EN 14214 (Europe), ASTM D6751-02 (US) and IS 15607 (India). Thus, Myxosarcina sp. can be utilized as the environmentally friendly biodiesel feedstock for high quality biodiesel production in the current scenario to meet escalating energy demand.