Biotransformation of Nitriles by Marine Fungi

Abstract

In this study, a screening of $12$ marine fungi (Penicillium miczynskii CBMAI 930, Penicillium raistrickii CBMAI 931, Aspergillus sydowii CBMAI 933, Aspergillus sydowii CBMAI 934, Aspergillus sydowii CBMAI 935, Bionectria sp. CBMAI 936, Penicillium oxalicum CBMAI 1185, Penicillium citrinum CBMAI 1186, Penicillium decaturense CBMAI 1234, Penicillium raistrickii CBMAI 1235, Cladosporium sp. CBMAI 1237, and Aspergillus sydowii CBMAI 1241) was conducted in order to evaluate the enzymatic potential of these microorganisms for biotransformation of phenylacetonitrile 1. These microorganisms were isolated from sponges and algae collected on the northern part of the coast of São Paulo State, Brazil. The screening was carried out on a solid mineral medium supplemented with glucose and phenylacetonitrile 1 as the only source of nitrogen. Afterwards, the microorganisms adapted were tested in a liquid medium containing $20$, $40$, and $60\mathrm{\mu }\mathrm{L}$ of phenylacetonitrile 1. The phenylacetonitrile 1 was biotransformed into the 2-hydroxyphenylacetic 1a acid by eight of the marine fungi selected. The enzymes which hydrolyzed nitriles in these catalytic systems were inducible. Since the mycelium of A. sydowii CBMAI 934 grew strongly in solid and liquid mineral media in the presence of phenylacetonitrile 1, this fungus was selected for the enzymatic hydrolysis reactions using other nitriles, such as 4-fluorophenylacetonitrile 2,4-chlorophenylacetonitrile 3, 4-methoxyphenylacetonitrile 4, cyclohexenylacetonitrile 5, and 2-cyanopyridine 14, yielding their corresponding carboxylic acids: 4-fluorophenylacetic 2a ($51\%$), 4-chlorophenylacetic 3a ($55\%$), 4-methoxyphenylacetic 4a ($43\%$), cyclohexenylacetic acid 5a ($28\%$), and the amide, 2-pyridinecarboxamide 14a, respectively. This chapter reports on the study on the biotransformation of nitriles by marine microorganisms which is summarized in the context of directions for future research.