Preliminary technical-economic analysis of biodiesel production from Haematococcus pluvialis residual biomass

Haematococcus pluvialis ( H. pluvialis ) microalgae are renowned as one of the richest sources of the antioxidant astaxanthin. During the extraction of this antioxidant, a large amount of triglyceride-rich biomass is discarded each year, which can be valorised to produce biodiesel. From this perspective, this study evaluates the industrial viability of producing biodiesel from this waste, considering four main scenarios that assess the profitability of glycerol purification as a by-product and the use of centrifugation or decantation in the separation stages. In these scenarios, the unit cost of biodiesel production ranged from 0.48 to 0.63€/kg. In addition, shorter payback periods of 8.82–8.88 years were obtained for the scenarios involving the purification and sale of biodiesel. Differences between centrifugation and decantation were negligible in the short term, with decantation proving advantageous over the long term. • Residual astaxanthin biomass is a potential feedstock for biodiesel production. • The use of centrifugation and decantation as separation stages was evaluated. • Centrifugation and glycerol purification were identified as the optimal scenario. • Unit production costs were 43 % lower than those reported for other oilseed crops. • Scenarios involving purification and biodiesel sale yielded shorter payback periods.