Biodiesel production from Nannochloropsis microalgal biomass‐derived oil: An experimental and theoretical study using the RSM‐CCD approach

Abstract

AbstractBiodiesel production from Nannochloropsis is investigated in the current study. Based on the extraction studies, the used biomass is composed of 50% saponifiable lipids, which turns this species to a vulnerable feedstock for biodiesel production. It should also be noted that the acidity of the obtained crude bio‐oil is higher than 2 mg KOH/g, hence it was attempted to survey the biodiesel production from the obtained oil through the esterification reaction with the aid of response surface methodology (RSM). According to the data, the highest biodiesel yield (99.5%) from the bio‐oil is obtained at a reaction temperature of 69°C, a reaction time of 30 min, a methanol to oil molar ratio of 9:1, and an H2SO4 concentration of 0.13 wt.%. In the next step, the in‐situ extraction and esterification of Nannochloropsis were investigated at the observed optimum reaction conditions. Based on the analysis, biodiesel yield from the dry cell weight of the biomass is considered to be 16%, which accounts for 99% conversion of bio‐oil to biodiesel.