André L.M. Porto

Bioreduction of fluoroacetophenones by the fungi Aspergillus terreus and Rhizopus oryzae

The enantioselective bioreduction of a number of fluoroacetophenones was carried out with whole cells of Rhizopus oryzae CCT 4964, Aspergillus terreus CCT 3320 and Aspergillus terreus CCT 4083 giving the corresponding alcohols in good yield and high enantioselectivity. Initial results with these fungi indicated that some of them are promising biocatalysts for deracemization reactions of secondary alcohols.

Biodegradation of methyl parathion by whole cells of marine-derived fungi Aspergillus sydowii and Penicillium decaturense.

Seven marine fungi strains (Aspergillus sydowii CBMAI 934, A. sydowii CBMAI 935, A. sydowii CBMAI 1241, Penicillium decaturense CBMAI 1234, Penicillium raistrickii CBMAI 931, P. raistrickii CBMAI 1235, and Trichoderma sp. CBMAI 932) were screened by their growth in the presence of methyl parathion (MP) in a solid culture medium. The strains with best growth were A. sydowii CBMAI 935 and P. decaturense CBMAI 1234. Biodegradation reactions were performed in 10, 20 and 30d in a malt extract liquid medium containing commercial MP and whole cells of A. sydowii CBMAI 935 and P. decaturense CBMAI 1234. In 20d, A. sydowii CBMAI 935 was able to degrade all pesticide, whereas P. decaturense CBMAI 1234 promoted a complete degradation in 30d. A. sydowii CBMAI 935 and P. decaturense CBMAI 1234 could degrade the product of the MP enzymatic hydrolysis, p-nitrophenol, on average of 51 and 40% respectively. Both strains used MP as a sole source of carbon and provided satisfactory results. Metabolites detected in the medium showed that the presumable reaction pathway occurred through the activation of MP to its more toxic form, methyl paraoxon, which was further degraded to p-nitrophenol.

Marine Fungi Aspergillus sydowii and Trichoderma sp. Catalyze the Hydrolysis of Benzyl Glycidyl Ether

Whole cells of the marine fungi Aspergillus sydowii Gc12, Penicillium raistrickii Ce16, P. miczynskii Gc5, and Trichoderma sp. Gc1, isolated from marine sponges of the South Atlantic Ocean (Brazil), have been screened for the enzymatic resolution of (±)-2-(benzyloxymethyl)oxirane (benzyl glycidyl ether; 1). Whole cells of A. sydowii Gc12 catalyzed the enzymatic hydrolysis of (R,S)-1 to yield (R)-1 with an enantiomeric excess (ee) of 24–46% and 3-(benzyloxy)propane-1,2-diol (2) with ee values <10%. In contrast, whole cells of Trichoderma sp. Gc1 afforded (S)-1 with ee values up to 60% and yields up to 39%, together with (R)-2 in 25% yield and an ee of 32%. This is the first published example of the hydrolysis of 1 by whole cells of marine fungi isolated from the South Atlantic Ocean. The hydrolases from the two studied fungi exhibited complementary regioselectivity in opening the epoxide ring of racemic 1, with those of A. sydowii Gc12 showing an (S) preference and those of Trichoderma sp. Gc1 presenting an (R) preference for the substrate.

Syntheses of Enantiopure Aliphatic Secondary Alcohols and Acetates by Bioresolution with Lipase B from Candida antarctica

The lipase B from Candida antarctica (Novozym 435®, CALB) efficiently catalyzed the kinetic resolution of some aliphatic secondary alcohols: (±)-4-methylpentan-2-ol (1), (±)-5-methylhexan-2-ol (3), (±)-octan-2-ol (4), (±)-heptan-3-ol (5) and (±)-oct-1-en-3-ol (6). The lipase showed excellent enantioselectivities in the transesterifications of racemic aliphatic secondary alcohols producing the enantiopure alcohols (>99% ee) and acetates (>99% ee) with good yields. Kinetic resolution of rac-alcohols was successfully achieved with CALB lipase using simple conditions, vinyl acetate as acylating agent, and hexane as non-polar solvent.

Stereoselective Bioreduction of 1-(4-Methoxyphenyl)ethanone by Whole Cells of Marine-Derived Fungi

Nine strains of marine-derived fungi (Aspergillus sydowii Ce15, A. sydowii Ce19, Aspergillus sclerotiorum CBMAI 849, Bionectria sp. Ce5, Beauveria felina CBMAI 738, Cladosporium cladosporioides CBMAI 857, Mucor racemosus CBMAI 847, Penicillium citrinum CBMAI 1186, and Penicillium miczynskii Gc5) were screened, catalyzing the asymmetric bioreduction of 1-(4-methoxyphenyl)ethanone 1 to its corresponding 1-(4-methoxyphenyl)ethanol 2. A. sydowii Ce15 and Bionectria sp. Ce5 produced the enantiopure (R)-alcohol 2 (>99% ee) in accordance with the anti-Prelog rule and, the fungi B. felina CBMAI 738 (>99% ee) and P. citrinum CBMAI 1186 (69% ee) in accordance with the Prelog rule. Stereoselective bioreduction by whole cells of marine-derived fungi described by us is important for the production of new reductases from marine-derived fungi.

Biocatalysis and biotransformation in Brazil: An overview.

This review presents the recent research in biocatalysis and biotransformation in Brazil. Several substrates were biotransformed by fungi, bacteria and plants. Biocatalytic deracemization of secondary alcohols, oxidation of sulfides, sp(3) CH hydroxylation and epoxidation of alkenes were described. Chemo-enzymatic resolution of racemic alcohols and amines were carried out with lipases using several substrates containing heteroatoms such as silicon, boron, selenium and tellurium. Biotransformation of nitriles by marine fungi, hydrolysis of epoxides by microorganisms of Brazilian origin and biooxidation of natural products were described. Enzymatic reactions under microwave irradiation, continuous flow, and enzymatic assays using fluorescent probes were reported.

Bioreduction of substituted a-tetralones promoted by Daucus carota root

The bioreduction of a series of substituted a-tetralones, carried out using Daucus carota root (carrot), afforded the corresponding homochiral a-tetralols in variable conversions (9 to 90%) and excellent enantiomeric excesses. Two of the assayed a-tetralones were resistant to the bioreduction conditions. The absolute configurations of four a-tetralols were assigned as being (S), by comparison to the (S)-enantiomers obtained by kinetic resolution promoted by CALB-catalysed acetylation. Additionally, the new 5-methoxy-6-methyl-1-tetralone was synthesized in seven steps from 3-methylsalicylic acid.

Bioconversion of Iodoacetophenones by Marine Fungi

Nine marine fungi (Aspergillus sclerotiorum CBMAI 849, Aspergillus sydowii Ce19, Beauveria felina CBMAI 738, Mucor racemosus CBMAI 847, Penicillium citrinum CBMAI 1186, Penicillium miczynskii Ce16, P. miczynskii Gc5, Penicillium oxalicum CBMAI 1185, and Trichoderma sp. Gc1) catalyzed the asymmetric bioconversion of iodoacetophenones 1–3 to corresponding iodophenylethanols 6–8. All the marine fungi produced exclusively (S)-ortho-iodophenylethanol 6 and (S)-meta-iodophenylethanol 7 in accordance to the Prelog rule. B. felina CBMAI 738, P. miczynskii Gc5, P. oxalicum CBMAI 1185, and Trichoderma sp. Gc1 produced (R)-para-iodophenylethanol 8 as product anti-Prelog. The bioconversion of para-iodoacetophenone 3 with whole cells of P. oxalicum CBMAI 1185 showed competitive reduction–oxidation reactions.

Biodegradation of the Organophosphate Pesticide Profenofos by Marine Fungi

Pesticides play an important role in modern agriculture. Synthetic pesticides are recognized as a cost-effective method of controlling pests, improving productivity and food quality. However, while pesticides may have a beneficial effect on agricultural productivity, their indiscriminate use causes many serious problems to the environment and human health, since these compounds are toxic to non-target species (Diez, 2010; Coutinho et al., 2005).

A new functionalized MCM-41 mesoporous material for use in environmental applications

Este trabalho descreve a sintese e caracterizacao de um novo adsorvente mesoporoso que consiste o MCM-41 funcionalizado com o acido p-aminobenzoico modificado (PABA-Si). A sintese foi realizada pelo metodo hidrotermal/co-condensacao. O PABA-MCM-41 foi caracterizado usando FTIR, SAXS, adsorcao/desorcao de N2, MEV e TG. Os experimentos em batelada foram utilizados para determinar os efeitos da concentracao inicial do adsorbato, tempo de contato e temperatura. A adsorcao do benzo[a]pireno (B[a]P) alcancou o equilibrio depois de 90 min (qe = 27,2 µg g-1) e concentracoes mais altas do adsorbato foram associadas com o aumento, em ambos, da percentagem de remocao (71,0-95,7%) e no valor de qe (20,1-27,1 µg g-1). A adsorcao seguiu o modelo cinetico de pseudo-segunda ordem, e se ajustou ao modelo de isoterma de Langmuir. Foi verificado em temperaturas mais altas um aumento na taxa inicial de adsorcao e na constante cinetica. Os parâmetros termodinâmicos indicaram que o processo foi espontâneo, endotermico e com uma tendencia para desordem.