A search was undertaken for microorganisms that can catalyze the enzymatic production of amoxicillin. Pseudomonas melanogenum KY 3987 was selected from our stock cultures, β- Lactamase-deficient mutants were isolated from amoxicillin-sensitive mutants derived from this strain. These mutants became sensitive to other penicillins and cephalosporins as well as amoxicillin and did not produce β-lactamase even in the presence of an inducer, such ...
