[Induced mutagenesis in Escherichia coli--a producer of penicillin acylase].

The action of certain chemical mutagens such as N-nitroso methyl urea, N-nitroso ethyl urea, N-nitroso dimethyl urea and N-nitroso methyl biuret, as well as physical ones such as UV light on Escherichia coli producing penicillin acylase was studied. High mutagenic activity of N-nitroso methyl biuret with respect to this culture was shown.