Enhanced degradation of lignosulfonated compounds by Streptomyces viridosporus

Degradation of lignosulfonated compounds by S. viridosporus strain T7A on n utritive or mineral culture media was quantified. Two lignosulfonated compo unds, differing in their molecular mass distributions and chemical structur es, were used: lignosulfonate (1-80 kDa) and vanisperse, a sulfonated oxyli gnin (1-20 kDa). The use of nutritive culture medium (containing Biosoyase) enhanced both the growth of S. viridosporus and production of lignin perox idase (LIP) leading to enhanced lignocellulose degradation, but no lignosul fonated compound degradation was observed. A fraction of these compounds un derwent a molecular transformation, producing non-biodegradable acid precip itable polymeric lignin (APPL). When a mineral culture medium (containing g lycerol as additional organic carbon source) was used, approximately 21 and 35% of lignosulfonate and vanisperse were respectively degraded, with litt le APPL production. LiP activity was growth-associated and significant modi fications of molecular mass distributions of both lignosulfonated compounds were observed. A mixed natural microbial population. collected in an aerat ed lagoon treating Fluff pulp effluent, was used to evaluate the biodegrada bility of lignosulfonate products from S. viridosporus cultures. This popul ation was (i) unable to degrade lignosulfonate products, and (ii) decreased the lignosulfonate degradation capacity of S. viridosporus. Antagonistic e ffects of the mixed population on S. viridosporus were observed. In the lig ht of this, bioaugmentation strategies involving addition of S. viridosporu s are unlikely to be successful and alternative degradation strategies need to be developed. (C) 1998 Published by Elsevier Science Ltd. All rights re served.