The effect of amino acids and amino acid analogues on growth of an obligate methanotroph, Methylosinus trichosporium OB3b

Abstract

AbstractThe sensitivity of the obligate methanotroph, Methylosinus trichosporium OB3b to a number of amino acid analogues and amino acids has been examined. Sulphaguanidine (5 μg ml−1) norleucine (100 μg ml−1) m‐fluorophenylalanine (50 μg ml−1), p‐fluorophenylalanine (50 μg ml−1) and S2‐aminoethyl‐C‐cysteine (1000 μg ml−1) inhibited growth. Proline, threonine, methionine and lysine (2–4 μg ml−1) also inhibited growth, but arginine and leucine at similar concentrations had no effect. Attempts were made to isolate amino acid analogue resistant mutants, which would be expected to overproduce amino acids. Two approaches were made, selection of spontaneous and induced mutants in plate culture, and selection of a spontaneous mutant during growth in continuous culture under selective conditions, but no mutants were obtained. Possible reasons for failure to obtain such mutants are discussed.