Application of Factorial Design Methodology for Optimization of Transesterification Reaction of Microalgae Lipids

This study investigates the effects of alkali catalyst quantity, reaction temperature, reaction time, and acid catalyst quantity on biodiesel production via the transesterification of microalgae using two-level four-factor full factorial design. Under the experimental range considered, the most important factor for FAME yield is the base catalyst quantity. The FAME yield increases with increasing base catalyst quantity. The reaction time and acid catalyst quantity also have positive influences. There is an appreciable interaction between alkali catalyst quantity and the acid catalyst quantity, and thus the effects of these variables must be considered jointly. The best results for laboratory-scale biodiesel production via transesterification were obtained at a 1:65 weight ratio of dry microalgal biomass to alkali catalytic methanol (NaOH/MeOH, 2.5 wt.%), with the acid catalysis process (HCl/MeOH, 5.8 vol.%), a 60oC reaction temperature, and a 30-min reaction time.