Sawdust Biodegradation: Cellulase and Ligninase Production via Submerged Fermentation and Glucose Production by Streptomyces lazureus

Abstract

Forty streptomycetes were isolated from the soils of farms in Riyadh. Only three isolates (St-2, St-9, and St-25) exhibited cellulolytic-ligninolytic activity, with the St-9 isolate exhibiting the highest activity and identified as Streptomyces lazureus. The optimum environmental and nutritional conditions for maximum cellulolytic-ligninolytic activity were determined as fermentation batch of pH of 7.5, inoculum size of 200 µL of bacterial suspension, incubation period of 7 d, and incubation temperature of 30°C. In addition, the fermentation batch contained peptone and yeast extract as the best nitrogen and carbon sources, respectively. Cellulase and ligninase were purified via gel filtration column chromatography. The accumulated end-product of the fermentation process was glucose powder, which was subjected to a partial characterization process. The glucose powder appeared white, melted at 146°C, was highly soluble in water, slightly soluble in ethanol, and insoluble in ethyl ether. The glucose solution appeared clear without precipitates and had a low electric conductivity of 15 µS.cm-1.