Tailoring chain length selectivity of a solvent-tolerant lipase activity from Aspergillus niger MYA 135 by submerged fermentation

Abstract

The use of biocatalysts in fuel industry is an interesting and greener alternative. In this connection, it was found that the chain-length selectivity profile of a solvent-tolerant lipase activity from Aspergillus niger MYA 135 determined in both hydrolytic and synthetic reactions depended on the way that the enzyme was prepared. Indeed, a mycelium-bound (Mb) lipase activity obtained either in presence or absence of 2% olive oil as well as a lyophilized supernatant extract obtained in presence of 2% olive oil showed different specificity constants (1/α). Thus, the highest substrate specificity in hydrolysis reaction was observed toward a long-chain fatty acid (C18; 1/α=1.0) with the constitutive Mb-lipase in organic medium. In addition, this lipase preparation was specific toward the synthesis of methyl palmitate during esterification (1/α=1.00) and ethyl palmitate in transesterification (1/α=0.93). Interestingly, the induced Mb-lipase was a highly reactive biocatalyst preparation in both transesterification (58% of the reactions displayed 1/α>0.5) and esterification (88% of the reactions displayed 1/α>0.7) reactions. On the contrary, the induced lyophilized supernatant was the most specific enzymatic system showing a clear preference for linoleic acid in esterification reactions (1/α around of 0.77 for all acyl acceptors tested).