CATABOLIC ACTIVITY ON HUMIC ACIDS OF STREPTOMYCES-VIRIDOSPORUS GROWN UNDER OXYGEN

When Streptomyces viridosporus was grown in batch culture on mineral s alts - glucose medium and under oxygen, aerial mycelium formation and sporulation were suppressed. Under these conditions, biodegradation of soil or synthetic humic acids (expressed as the rate of decolorizatio n of growth medium and the loss of radioactivity of labeled melanoidin , respectively) increased. Concurrently, both the catabolic activity o f cells (expressed as peroxidase production, measured by the oxidation of N,N,N',N'-tetramethyl-1,4-phenylenediamine as substrate) and the e xcretion of siderophores were stimulated.