Biodegradation of an s-triazine herbicide, simazine

Two types of simazine-degrading microorganisms were isolated from soil samples where the herbicide had been spread with the enrichment culture using simazine as the sole carbon and nitrogen source. A fungal strain, DS6F, identified as Penicillium steckii, is the first simazine-degrading fungus ever reported. Ž Simazine was gradually degraded by P. steckii DS6F in the mineral medium containing simazine initial concentration: . 50 mgrl and 25 mgrl of yeast extract. The rate of simazine degradation was improved when assimilable carbon sources were added into the medium, and the reduction rate of 53% was obtained after 5 days of cultivation at 308C when glucose was added into the basal medium. Ž . The bacterial strain, N5C, identified as Moraxella Branhamella oÕis, was newly isolated and proven to degrade simazine more effectively than strain, DS6F, and 200 mgrl of simazine disappeared almost completely within 5 days at 358C. Ž . M. Branhamella oÕis could also degrade another s-triazine herbicide, atrazine, at the similar reduction rate as simazine. q 2001 Elsevier Science B.V. All rights reserved. Ž .