Expression of thermostable bacterial β-glucosidase (BglB) in transgenic tobacco plants

Transgenic tobacco plants expressing the hyperthermostable B-glucosidase BglB of Thermotoga mamma were generated with the goal of cost-effective production of the enzyme for the application in bioconversion of lignocellulosic biomass. The enzyme was targeted to the cytosol and chloroplasts, where it accumulated to level of 4.5% and 5.8% of total soluble protein, respectively The optimal temperature and pH of the plant-expressed BglB was 80 degrees C and 4.5, respectively. BglB activity was preserved in leaves after lyophilization, but decreased by over 70% with drying at room temperature When BglB was synergistically supplied in a 1% (w/v) rice straw with Cel5A for efficient cellulase conversion, a 37% increase in glucose was observed This report demonstrates the potential of utilizing transgenic tobacco for mass production of BglB. (C) 2010 Elsevier Ltd All rights reserved