Two-step statistical optimization for cold active β-glucosidase production from Pseudomonas lutea BG8 and its application for improving saccharification of paddy straw

• Published in: Biotechnology and applied biochemistry 2016-09, Vol.63 (5), p.659-668
• Main Authors: Tiwari, Rameshwar, Pranaw, Kumar, Singh, Surender, Nain, Pawan K.S., Shukla, Pratyoosh, Nain, Lata
• Format: Article
• Language: English
• Subjects: beta-Glucosidase - biosynthesis; beta-Glucosidase - metabolism; bioreactor; Bioreactors - microbiology; Biotechnology - methods; Box-Behnken design; Carbohydrates - chemistry; Cellulase; Cold Temperature; Enzymes; Fermentation; Flasks; Kinetics; Nanostructure; Optimization; Plant Extracts - chemistry; Pseudomonas; Pseudomonas - metabolism; Saccharification; Statistics as Topic; Straw; Taguchi experimental design
• ISSN: 0885-4513; 1470-8744
• DOI: 10.1002/bab.1415

β‐Glucosidase is an essential part of cellulase enzyme system for efficient and complete hydrolysis of biomass. Psychrotolerant Pseudomonas lutea BG8 produced β‐glucosidase with lower temperature optima and hence can play important role in bringing down the energy requirement for bioethanol production. To enhance β‐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 β‐glucosidase under submerged fermentation. The optimal medium composition for maximum β‐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 °C. Under optimized conditions, β‐glucosidase production increased up to 9.12‐fold (17.52 ± 0.24 IU/g) in shake flask. Large‐scale production in 7‐L stirred tank bioreactor resulted in higher β‐glucosidase production (23.29 ± 0.23 IU/g) within 80 H of incubation, which was 1.34‐fold higher than shake flask studies. Commercial cellulase (Celluclast® 1.5L) when supplemented with this crude β‐glucosidase resulted in improved sugar release (548.4 ± 2.76 mg/gds) from paddy straw at comparatively low temperature (40 °C) of saccharification. P. lutea BG8 therefore showed great potential for cold active β‐glucosidase production and can be used as accessory enzyme along with commercial cellulase to improve saccharification efficiency.