Influence of amino acids, carboxylic acids and sugars on the growth of Methylococcus capsulatus on methane.

Abstract

SUMMARY The influence of 3 types of compounds (L-amino acids, carboxylic acids and sugars) on the growth of Methylococcus capsulatus in Petri dishes was investigated. Increase in colony diameter was used as the growth parameter. L-amino acids and carboxylic acids which are normal metabolic intermediates prevented growth in low concentrations. Threonine, leucine, histidine and glycine were especially inhibitory; c. 0.01% was sufficient to suppress growth completely. Glutamic acid at 0.1 % concentration completely suppressed growth but at 0.005% markedly stimulated growth; similar effects were shown by lysine, methionine, glutamic acid, tryptophane, tyrosine, proline and citric acid. Among the sugars, glucose was the most potent growth inhibitor; maltose and sucrose had practically no effect.