Loss of butylate-utilizing ability by a Flavobacterium

Flavobacterium sp. strain VI.15 (But +) was isolated from a vernolate-history soil employing an indicator medium (MSBT). This organism was capable of utilizing butylate (But +), EPTC (Ept +), and vernolate (Ver +) as a primary carbon source. Butylate-minus derivatives of the herbicide-utilizing wild-type were isolated on MSBTE differential indicator composed of minimal salts + 200 μg ml −1 butylate + 70 μg ml −1 yeast extract + 25 μg ml −1 2,3,5-triphenyltetrazolium chloride. VI.15 (But +) was plated on the differential indicator and plasmid moieties present within this bacterium were induced to segregate. Loss of pSMB2 as a function of physical (temperature) and acridine orange-curing corresponded with a loss of butylate-utilizing ability. Moreover, spontaneous loss of carbamothioate-utilizing abilites upon cold storage (4°C) on minimal media further suggested plasmid involvement in carbamothioate biodegradation.