beta-Glucosidase is an essential part of cellulase enzyme system for efficient and complete hydrolysis of biomass. Psychrotolerant Pseudomonas lutea BG8 produced -glucosidase with lower temperature optima and hence can play important role in bringing down the energy requirement for bioethanol production. To enhance -glucosidase production, two statistical tools: Taguchi and Box-Behnken designs were applied to reveal the most influential factors and their respective concentration for maximum production of -glucosidase under submerged fermentation. The optimal medium composition for maximum -glucosidase production were 2.99% (w/v) bagasse, 0.33% (w/v) yeast extract, 0.38% (w/v) Triton X-100, 0.39% (w/v) NaNO3, and pH 8.0 at temperature 30 degrees C. Under optimized conditions, -glucosidase production increased up to 9.12-fold (17.52 +/- 0.24IU/g) in shake flask. Large-scale production in 7-L stirred tank bioreactor resulted in higher -glucosidase production (23.29 +/- 0.23IU/g) within 80H of incubation, which was 1.34-fold higher than shake flask studies. Commercial cellulase (Celluclast((R)) 1.5L) when supplemented with this crude -glucosidase resulted in improved sugar release (548.4 +/- 2.76mg/gds) from paddy straw at comparatively low temperature (40 degrees C) of saccharification. P. lutea BG8 therefore showed great potential for cold active -glucosidase production and can be used as accessory enzyme along with commercial cellulase to improve saccharification efficiency. (C) 2015 International Union of Biochemistry and Molecular Biology, Inc.