Optimization of Lipase Catalyzed Biofuel Synthesis From Waste Filter Coffee Using Response Surface Methodology
Abstract This study was executed that optimize an environmentally friendly lipase (Resinase® HT with the activity of 135,56 U/ml) catalyzed transesterification process from novel feedstock waste filter coffee oil for biofuel production. Response surface methodology (RSM) with the central composite design was performed to investigate the effect of experimental factors (enzyme content, oil/methanol molar ratio, reaction temperature) on the fatty acid methyl ester (FAME) conversion and also investigated to resolve the optimum design points. After the experimental studies the lowest FAME conversion was found as 71% when the enzyme content was 15%(%gr w/w), oil/methanol molar ratio was 0.17 and the reaction temperature value was 45 °C. According to the design response, 70.83% was observed in the same conditions. The highest FAME conversion of 97% was found when the enzyme content was 5%(%gr w/w), oil/methanol molar ratio was 0.25 and the reaction temperature value was 35 °C. The experimental run gave the FAME conversion of 96.80% at the same reaction conditions. The model fitted with the experimental values with R2 = 0.98. Also, classical soxhlet extraction and Dyer method oil yields were compared. 24 % and 20 % oil removed from waste coffee grounds in traditional soxhlet and Dyer method respectively. The extraction process took 30 minutes with the soxhlet method and 45 minutes with the Dyer method. The results are promising for the application of lipase catalyst for environmentally friendly and sustainable biodiesel production from waste coffee oils all over the world.