Seleção de isolados fúngicos amazônicos produtores de lipases para biocatálise enantiosseletiva em meio orgânico

Abstract

Lipases (3.1.1.3) are highly versatile enzymes for biocatalysis. The synthetic and enantioselective activity of these enzymes in organic medium has application in the production of high value-added chemicals, such as chiral blocks for synthesis and enantiopure drugs. The search for microorganisms that supply new lipases useful for biotechnology remains a topic of great relevance. We investigated in this study the biomass potential of six Aspergillus strains and fourteen unidentified fungal strains, all collected in the Amazon region, as a source of mycelial-bound lipases for biocatalysis applications, both in aqueous medium (hydrolytic activity) and in organic medium (synthetic and enantioselective activity). The effect of three biomass treatments on hydrolytic activity was compared. The synthetic activity was evaluated by a transesterification assay and quantified by two different methodologies. The enantioselective capacity of lipases was evaluated by resolution of the drug (R, S) - ibuprofen. We verify that, for fifteen isolates, the delipidated biomass presented better results in the hydrolysis of p-nitrophenyl palmitate compared to the other two treatments. The delipidated biomass of six strains of Aspergillus and UEA_115 strain presented high ethyl palmitate synthesis activity by transesterification in organic medium. The results were confirmed by spectrophotometry (410 nm) and gas chromatography. In this reaction, the isolate DPUA_1539 A. flavo-furcatis achieved the maximum value of 668.5 ± 23.5 mU.g-1. Enantioselective activity assays indicated that biomass-bound lipases of the isolates UEA_115 (E = 3.58; ees = 7 ± 0) and, in particular, of the isolate DPUA_1539 A. flavo-furcatis (E = 24.15; ees = 91 ± 1), have the ability to discriminate the enantiomers of the drug ibuprofen by the synthesis of ester, preferably with the (R)-enantiomer. These results encourage further investigations of these fungi as potential suppliers of lipase for biocatalytic processes, such as the production of biodiesel and the production of enantiopure drugs.