Asian Journal of Microbiology and Biotechnology

The production of alginate and curdlan is important because they are increasingly required for a variety of industrial and biological applications. Currently, the primary carbon sources used in the industrial production of alginate and curdlan are sucrose and glucose, which are very expensive. This study therefore examined the suitability of corncob, sawdust and rice husk as potential substrates for the production of alginate and curdlan by evaluating their chemical properties. Rice husks, corncob and sawdust were collected from mills in Jimeta metropolis and Girei LGA in Adamawa State, Nigeria, and subjected to chemical content analysis. Their hemicellulose, lignin, and ash contents were determined following standard methods, and isolated Agrobacterium and Azotobacter species were used to test their suitability for alginate and curdlan production. Results showed that all the substrates contained ash, cellulose and hemicellulose; sawdust had the highest percentage (52%) of ash; corncob had the highest value of 31.1 ± 2.0% for cellulose and 24.1±24.1% for hemicellulose; sawdust recorded the highest value of 70.9±3.0 for lignin; Agrobacterium spp. cf6 yielded the highest curdlan (0.7 g/L) using rice husk as a substrate, whereas none of the Agrobacterium spp. isolates yielded curdlan when cultured on sawdust as a carbon source. Corncob and rice husk have suitable physicochemical properties and can be used as substrates by Agrobacterium and Azotobacter species for the production of alginate and curdlan. However, pretreatment before use and subsequent optimisation are needed to boost yield.