BACTERIAL UTILIZATION OF LIGNANS I

Abstract

Species belonging to the genera Pseudomonas, Flavobacterium and Achromo-bacter capable of dissimilating [alpha]-conidendrin have been isolated from widely separated geographical locations by means of enrichment culture techniques. Sample sources included manure, soil, decaying wood, and forest litter as well as mud and water from below paper mill effluent outfalls. Although active genera were common to all sample sources, pseudomonad strains were most numerous and most active while species of the genera Flavobacterium and Achromobacter showed lesser efficiency to utilize the lignan. Progressive selection procedures further increased the efficiency of the isolates. Mixed cultures appeared to be more efficient than pure cultures. The alpha-conidendrin metabolized by mixed cultures at the end of 20 days ranged from 6361 to 95.43%. Pure cultures utilized from 57.75 to 92.17% of the substrate in 20 days. Chromatographic analysis of the extracts from supernatant fluids of the media has shown vanillic, para-hydroxybenzoic, protocatechuic and [beta]-ketoadipic acids to be the intermediate products of [alpha]-conidendrin degradation. Adaptation and growth response studies indicated that the metabolic pathway in the dissimilation of [alpha]-conidendrin by pseudomonad strains may proceed from [alpha]-conidendrin[long dash]* vanillic acid[long dash][center dot] para-hydroxybenzoic acid [long dash] protocatechuic acid[long dash] [beta]-keto-adipic acid.