Lignocellulose decomposition by selected streptomyces strains

From 30 actinomycete cultures isolated by enrichment technique on agar media containing newsprint as a primary carbon and energy source, three Streptomyces strains were selected for characterization of their lignocellulose-decomposing abilities. All three streptomycetes were capable of oxidizing specifically 14C-labeled lignocelluloses to 14CO2. These Streptomyces were shown to attack primarily the cellulosic (glucan) components, of which between 25 to 40% evolved as 14CO2 during 1,025 h of incubation depending upon the culture used. Lignin labeled lignocelluloses were also attacked, but to a lesser degree, with up to about 3.5% being oxidized to 14CO2 depending upon the culture used. Additionally, it was shown that purified 14C-labeled milled-wood lignin was attacked, with recoveries of up to 17.7% of the label was 14CO2. This is the first conclusive evidence to show that streptomycetes can decompose lignin.