Degradation of alkali-lignin residues from solid-state fermentation of wheat straw by streptomycetes

The ability of three Streptomyces strains to degrade alkali-lignin, produce d from the treatment of wheat straw by the same organisms, was examined. De colourisation and loss of alkali-lignin was only detected in cultures suppl emented with ammonium as an inorganic N source. The pH of cultures suppleme nted with inorganic N reached lower pH than in those supplemented with yeas t extract. From FT-IR spectra corresponding to the alkali-lignin obtained f rom the same cultures, a degradation of carbohydrate component concomitant with a modification in the aromatic moiety of lignin could be inferred. The results indicate that streptomycetes are suitable for use in the treatment of alkali-lignin effluents from the biological treatment of wheat straw by the same organisms and therefore support the role for these organisms in t he development of clean technologies in pulp and paper industry.