Oxidation of carbonyl compounds by whole-cell biocatalyst
ABSTRACT Acinetobacter junii was found to catalyse the oxidative biotransformation of benzaldehyde, 4-methoxybenzaldehyde, vanillin, 3,4-dimethoxybenzaldehyde, 3-methoxybenzaldehyde and phthalaldehyde within 48 h of incubation. During this process, the activities of drug-metabolizing enzymes, such as cytochrome P-450 and acetanilide hydroxylase were found to be increased significantly. Such an increase in activity indicates their involvement in the biotransformation processes. The purified biotransformed products of each carbonyl compound were characterized by H1 NMR and IR spectroscopy, confirming that oxidation to the corresponding carboxylic acid had occurred.
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ABSTRACT: ON the basis of extensive experimentation the concept was derived that aromatic amines and their acetyl derivatives had rather similar physiologic and pathologic effects.1,2 The underlying rationale seemed to be ready deacetylation of the acetyl derivatives and extensive acetylation of the amines by distinct known enzyme systems.3,4,5 On the assumption that the active entity was readily available by enzymic conversions, the chemically more stable acetyl derivatives were used in biologic and pharmacologic tests involving incorporation in diet or similar technics.Mesidine or 2,4,6-trimethylaniline, an industrial chemical, has been reported to be a hepatotoxic agent which under some circumstances was also carcinogenic.6,7 We have recently undertaken a chronic feeding study of -acetylmesidine (2′,4′,6′-trimethylacetanilide) in rats and we surprisingly found no distinct pathological effect. Earlier results in mice were also borderline or negative.8 Examination of models suggested that the two methyl groups to the amino substituent may interfer with biochemical reactions. This point was proven by subjecting -acetylmesidine to a rat liver homogenate in a system described previously.9,10 Whereas aniline was liberated very readily from acetanilide, no mesidine was found after incubation of the -acetyl derivative under identical conditions.Life Sciences 04/1968; 7(6):263-7. · 2.56 Impact Factor
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ABSTRACT: The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.Journal of Biotechnology 12/1998; 66(1):41-50. · 3.18 Impact Factor
Article: Multiple forms of microbial enzymes.[show abstract] [hide abstract]
ABSTRACT: Multiple forms of one enzyme occur in a wide variety of microorganisms. Their synthesis is often dependent on culture characteristics such as medium composition, physico-chemical parameters, culture age and the presence of inducing or inhibiting agents. Multiform enzymes increase the capability of the producing organism to adapt to and cope with a wide variety of environmental changes, such that the physiological advantages outweigh the apparent wasteful hyperproduction of multiple forms of one enzyme.Biotechnology Letters 08/2003; 25(14):1119-24. · 1.85 Impact Factor