An Examination of Bacterium thiocyanoxidans

Abstract

IN 1937 Happold and Key¹ isolated from sewage effluent treated with gas-works liquor an organism which was capable of multiplication in solutions containing only potassium or ammonium thiocyanate and phosphate. Ammonium sulphate and carbondioxide were produced. The organism grew to form small dewdrop colonies on agar containing only thiocyanate, but it also formed large yellowish-green colonies on the surface of ordinary ‘nutrient agar’. After growth on the latter medium, the organism failed to utilize thiocyanate when transferred to inorganic solutions, irrespective of the presence or absence of thiocyanate in the nutrient agar. Some time later² the isolation was made again, and the organism obtained showed all the same properties, including loss of the ability to utilize thiocyanate after growth to form yellowish-green pigmented colonies on media containing organic nutrients. During both isolation procedures, serial platings of the organism had been undertaken with successive selection of single colonies. The morphology of the organism and of the colonies formed on inorganic salt – agar medium appeared to be similar, although on the second occasion there was some evidence of the appearance of more than one type of colony on nutrient agar.