7-18: Novel enzyme from Streptomyces rochei on cellulose degrading

Biofuels are an attractive alternative to current petroleum-based fuels as they can be utilized as transportation fuels with little change to current technologies and have significant potential to improve sustainability and reduce greenhouse gas emissions. Cellulosic biomass derived from forestry and agriculture is potential feedstocks for the synthesis of biofuels.

Lignocellulosic materials are abundant all over the world. There are evidences that enzymatic hydrolysis of cellulose is considered to require the action of both cellobiase, endo-β- and exo-β- glucanases. To find these kinds of enzyme produced by new bacteria strain which could convert cellulose into monosaccharide efficiently, and then the monosaccharide can be utilized for fermentation to biofuels. A cellulase producing strain of Actinomycetes was isolated from soil samples with rice straw as sole nutrients. According to 16S rDNA and fatty acid composition analysis, this strain was defined as Streptomyces rochei HC327. S. rochei HC327 could produce xylanase, endo-β-glucanase and exo-β–glucanase at the same time without inducer supplying. Enzyme purification was performed. To our knowledge, this is the first study reporting an exo-β–glucanase (avicelase) from S. rochei. Synergistic effects were observed in increments in simultaneous reaction with purified enzymes. A xylanosome with cellulose-binding module could be developed by S. rochei HC327 to enhance the lignocellulose-degrading efficacy.