RESUMO
A bacterial strain producing a beta-lactam antibiotic acylase, able to hydrolyze ampicillin to 6-aminopenicillanic acid more efficiently than penicillin G, was isolated from soil and characterized. The isolate was identified as Achromobacter sp. using the phenotypic characteristics, composition of cellular fatty acids and 16S rRNA gene sequence. The enzyme synthesis was fully induced by phenylacetic acid (PAA) at a concentration of 2 g l(-1). PAA at concentrations up to 12 g l(-1) had no negative effect on the specific activity of acylase and biomass production, but slowed down the specific growth rate. Benzoic or 4-hydroxyphenylacetic acids can also induce synthesis of the enzyme. The inducers were metabolized in all cases. Acylase activity in cell-free extracts was determined with various substrates; ampicillin, cephalexin and amoxicillin were hydrolyzed 1.5- and 2-times faster than penicillin G. A high stability of acylase activity was observed over a wide range of pH (5.0-8.5) and at temperatures above 55 degrees C.
Assuntos
Achromobacter/enzimologia , Achromobacter/isolamento & purificação , Penicilina Amidase/metabolismo , beta-Lactamas/metabolismo , Achromobacter/classificação , Achromobacter/genética , Ácido Benzoico/metabolismo , DNA Ribossômico/química , Indução Enzimática , Estabilidade Enzimática , Genótipo , Concentração de Íons de Hidrogênio , Penicilina Amidase/biossíntese , Fenótipo , Fenilacetatos/metabolismo , Fenilacetatos/farmacologia , Filogenia , RNA Ribossômico 16S/genética , Microbiologia do Solo , Especificidade por Substrato , TemperaturaRESUMO
The cultivation of the yeast Trigonopsis variabilis producing D-amino-acid oxidase (an enzyme participating in the transformation of cephalosporin C into 7-aminocephalosporanic acid for the production of beta-lactam antibiotics) was controlled by changes of dissolved oxygen tension and extended fermentation times. The production technology was optimized on a laboratory scale and scale-up parameters were identified.
Assuntos
Ascomicetos/metabolismo , D-Aminoácido Oxidase/biossíntese , Ascomicetos/crescimento & desenvolvimento , Meios de Cultura , Fermentação , Concentração de Íons de Hidrogênio , Oxigênio/metabolismo , Fatores de TempoRESUMO
The production of L-lysine from DL-alpha-amino-epsilon-caprolactam (DL-ACL) by new strains producing L-alpha-amino-epsilon-caprolactamase and aminocaprolactam racemase is described. Optimal conditions for hydrolysis of L-ACL by Cryptococcus sp. and for racemization of ACL by cells of a strain isolated in nature and identified as Pseudomonas sp. were determined. Synthesis of L-alpha-amino-epsilon-caprolactamase is induced by DL-ACL or L-lysine with the same effectivity. A positive effect of phosphates (potassium salts) on reduction of the induction lag was detected, the synthesis of this enzyme was found to be repressed by glucose and some possibilities of the reversion of this repressive effect were demonstrated. Under conditions optimal for the production of both enzymes a quantitative theoretical conversion of 10% aqueous DL-ACL to L-lysine by a mixture of native cells in a mass ratio of 1 : 2 (producer of ACL-hydrolase to producer of ACL-racemase) occurred in 8 h at 40 degrees C and pH 8.0.
