Some Properties of a Pectolytic Soil Flavobacteriurn

SUMMARY: A pectolytic Flavobacterium sp. isolated from soil is described. It possesses a typical bacterial polygalacturonase but no pectin methyl esterase. Most previous studies on micro-organisms which decompose the pectic sub-stances of plants have centred round three topics: flax-retting, fruit-juice canning and the soft-rot diseases of plants. The only reported observation on the non-pathogenic pectolytic microflora of soil were made by Wieringa (1949). Wieringa devised a pectate gel plate which used the ability of sodium pectate to gel a t neutral pH values in the presence of calcium ion, thus producing a firm surface which could be streaked with a bacterial culture. On plating dilutions of an unspecified soil on this selective medium Wieringa found large numbers of actinomycetes. It has been assumed, largely from aetiological studies of the organism, that Emriniu carotovoru, which causes a soft-rot of plant storage organs, occurs in a wide range of soils; but the support for this theory seems largely to be the report (Kerr, 1953) that 20 soil samples from the North of Scotland all contained this organism. The present paper describes the isolation from soil of a hitherto undescribed organism which is pectolytic, possesses a polygalacturonase but no pectin methyl esterase, and is nutri-tionally non-exacting. These properties made it a suitable tool for more de-tailed studies on the production and properties of the polygalacturonase.