LAUSR

Abstract This work objective was to use different lipases in the methyl oleate synthesis. Endophytic fungi strains of Penicillium sumatrense and Aspergillus fumigatus were isolated from castor leaves (Ricinus communis L.) in order to acquire lipases through solid-state fermentation, using sunflower seeds as substrate. Following this, the fermented solid went through the process of obtaining the crude extract, drying or immobilization. From the enzymatic preparations, esterification reactions were performed, using oleic acid as a substrate. The enzyme immobilization and extraction resulted in loss of hydrolytic activity and reduction of esterification efficiency, showing about 70–80% of maximum conversion in 12 h of reaction. The fermented solid showed 90% conversion after 8 h reaction and after conditions optimization, it resulted in 100% conversion. The produced enzymes presented themselves to be suitable for reutilization, the A. fumigatus enzyme showed a half-life of 14 reuse cycles. The fermented solid addition have some advantages when compared to others enzymatic preparations such as lower activity loss, reduced obtainment costs and possibility for reutilization.