Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-01-02

Journal: BIOTECHNOLOGY & BIOTECHNOLOGICAL EQUIPMENT

Included Journals: EI、SCIE

Volume: 31

Issue: 1

Page Number: 23-28

ISSN: 1310-2818

Key Words: Thermostable cellulase; subcellular targeting; transgenic tobacco; transgenic rice

Abstract: The production of cellulases in plants is an economical method for the conversion of lignocellulosic biomass into fuels. Herein we report the expressions of two thermostable Acidothermus cellulolyticus cellulases, endo-1,4-beta-D-glucanase (E1) and exoglucanase (Gux1), in tobacco and rice. To evaluate the expression of these recombinant cellulases, we expressed the full-length E1, the catalytic domains of E1 (E1cd) and Gux1 (Gux1cd), as well as an E1-Gux1cd fusion enzyme in various subcellular compartments. In the case of tobacco, transgenic plants that expressed apoplast-localized E1 showed the highest level of activity, about three times higher than those that expressed the cytosolic E1. In the case of rice, the level of cellulase-specific activity in the transgenic plants ranged from 11 to 20 nmol 4-methylumbelliferone min(-1) mg(-1) total soluble protein. The recombinant cellulases exhibited good thermostability below 70 degrees C. Furthermore, transgenic rice leaves that were stored at room temperature for a month lost about 20% of the initial cellulase activity. Taken together, the results suggested that heterologous expression of thermostable cellulases in plants may be a viable option for biomass conversion.