We evaluated the biomass of twenty Amazonian fungal isolates as a potential source of mycelium-bound lipases with hydrolytic, synthetic or enantioselective activity for biocatalysis application. We compared the hydrolytic activity of three biomass treatments (delipidated, non-delipidated and cultivated in medium without inducer). Delipidated biomass showed better results in the hydrolysis of p-nitrophenyl palmitate compared to the other two treatments for fifteen isolates. Delipidated biomass of six Aspergillus strains and UEA_115 strain showed a high synthesis activity of ethyl palmitate by transesterification in organic medium. Results were confirmed by spectrophotometry (410 nm) and gas chromatography. In this reaction, the isolate DPUA_1539 A. flavo-furcatis reached a maximum value of 668.5 ± 23.5 mU g-1. Enantioselective activity assays indicated that biomass-bound lipases from UEA_115 isolate (E = 3.58; ees = 7 ± 0) and in particular from the DPUA_1539 A. flavo-furcatis isolate (E = 24.15; ees = 91 ± 1) have the ability to discriminate enantiomers of the drug ibuprofen by ester synthesis, preferably with (R)-enantiomer. These results encourage further investigations of these fungi as potential lipase suppliers for biocatalytic processes such as biodiesel production and enantiopure drugs.

Neste trabalho foram avaliados 212 fungos isolados de plantas da Região Amazônica quanto ao potencial de aplicação em biocatálise como fornecedores de lipases ligadas ao micélio. Estes isolados foram submetidos a ensaios de atividade hidrolítica e sintética. Quando submetidos ao ensaio com o substrato tributirina, 87% dos isolados apresentaram atividade hidrolítica. Destes, 30% mostraram bom crescimento em meio líquido indutor de lipase, e foram submetidos à avaliação sintética em reações de esterificação e transesterificação em solvente orgânico. Os nove fungos que apresentaram os melhores desempenhos sintéticos foram avaliados quanto a sua enantiosseletividade na reação de resolução do (R, S)-2-octanol. O isolado UEA_115 foi o biocatalisador mais versátil, apresentando bom desempenho nas reações de esterificação (conversão > 90%) e boa capacidade para a resolução do (R, S)-2-octanol (ee s 29%; ee p 99%; c 22%; E > 200). Com este estudo foi possível demonstrar o grande potencial dos fungos amazônicos como fornecedores de lipases para biocatálise.

In this study, 212 fungi were isolated from Amazon region plants, aiming to obtain mycelium bound-lipase-producing biocatalysts. These isolates were submitted to hydrolytic and synthetic activity assays. When submitted to the tributyrine substrate test, 87% of the isolates showed hydrolytic activity. Of these, 30% showed good growth in lipase inducing liquid media and were submitted to evaluation of synthetic activity in esterification and transesterification reactions in organic solvents. The nine fungi which had the best synthetic activity were evaluated in the (R, S)-2-octanol resolution reaction, in order to verify the enantioselectivity of mycelium-bound lipases. The isolate UEA_115 was the most versatile biocatalyst, showing good performance in esterification reactions (conversion > 90%) and good ability for the resolution of (R, S)-2-octanol (ee s 29%; ee p 99%; c 22%; E > 200). Thus, this study has demonstrated the great potential of the Amazonian fungi as lipase suppliers for biocatalysts.