Nutrient and salinity stress induced biodiesel production from a green alga, Monoraphidium neglectum

The potential of a green alga as a versatile and sustainable feedstock for biodiesel production was assessed. Molecular identification revealed the alga to be Monoraphidium neglectum. Under diverse growth conditions, including nutrient deficiency and salinity stress, the microalga showed robust adaptability. Under nitrate deficiency (N-, the lipid content peaked (30.67 %), with a notable increase in monounsaturated fatty acids (MUFA), reaching 50.72 % in the stressed sample. Additionally, the highest polyunsaturated fatty acid (PUFA) content (24.55 %) was observed at a salinity level of 0.12 M. At 0.01 M salinity, the highest total carbohydrate content was observed. A significant fatty acid methyl ester (FAME) yield of 85.08 % was obtained under nitrate deficiency (N-) emphasizing its biodiesel production potential. The as-obtained biodiesel exhibited low viscosity, superior low-temperature performance and enhanced oxidation stability rendering the alga as an ideal candidate for eco-friendly, sustainable biodiesel production.