Effect of Streptomycetes viridosporus T7A on kraft lignin

Abstract

The ability of the lignino-cellulolytic actinomycete Streptomycetes viridosporus T7A to attack purified fractions of kraft lignin was examined. In the presence of 0.3% yeast extract, high-molecular weight kraft lignin (MW > 3000, ether-insoluble fraction) does not affect growth of this microorganism significantly, where as low-molecular weight kraft lignin (MW < 3000 ether-soluble fraction) inhibits its development. Accordingly, average molecular weight of the ether insoluble fractions after bacterial growth remained unaltered, as measured by Sephadex G-50 gel permeation chromatography. Slight modifications were detected by high performance liquid chromatography in the ether-soluble fraction after incubation with the microorganism. S. viridosporus T7A partially decolorizes Remazol Brilliant Blue R during growth on wheat lignocellulose. However, decolorization of either fraction of kraft lignin was not observed. These results suggest that the filamentous bacterium S. viridosporus T7A is not suitable for pulp mill effluent treatment.