SCREENING AND CHARACTERIZATION OF MICROORGANISMS WITH GLUTARYL-7ADCA ACYLASE ACTIVITY

A screening of microorganisms producing glutaryl-7ADCA acylase, an enz yme able to hydrolyse glutaric acid selectively from glutaryl-3-deacet oxy-7-aminocephalosporanic acid (glutaryl-7ADCA), has been carried out in soil samples. Five microorganisms expressing acylase activity were isolated and classified as Bacillus cereus, Achromobacter xylosooxida ns, Bacillus sp., Pseudomonas sp. and Pseudomonas paucimobilis. The sc reening was carried out by preparing enrichment cultures containing gl utaryl-7-ADCA or cephalosporin C as the selective carbon source. Four model compounds (adipoyl-, glutamyl- and glutaryl-p-nitroanilide and g lutarylcoumarin), mimicking the glutaryl-7ADCA beta-lactam moiety, wer e synthesized as substrates suitable for the rapid screening of the mi croorganisms (2500) isolated from the enrichment cultures. A total of 300 strains were active on the model substrates and only 5 displayed a cylase activity on glutaryl-7ADCA. The fermentation parameters, such a s pH and inducer concentration, for the optimal acylase expression and acylase specificity towards the model substrates were different for e ach strain.