Biodegradation of three different wood chips by Pseudomonas sp PKE117

Biodegradation of wood chips of broad-leaved trees Eucalyptus grandis x Eucalyptus urophylla and Populus canadensis, and of the conifer Larix olgensis by Pseudomonas sp. PKE117 was studied. After 60 days of biopulping by PKE117, the weight losses of E. grandis x E. urophylla, P. canadensis and L. olgensis were 7.58%, 17.15% and 26.75%, respectively. Elemental analysis showed that the C, H contents of three wood chips decreased and 0 content increased after the biopulping. FT-IR results also showed that the lignin structure was destroyed more than that of cellulose. Solid-state CP/MAS 13C-NMR spectroscopy results showed that the content of guaiacylpropanoid (G) lignin-unit in lignin of three samples decreased after biodegradation. The hemicellulose in L. Olgensis decreased much more than other samples. All the results demonstrated that the degradation of L. olgensis by Pseudomonas sp. PKE117 was more efficient than that of P. canadensis and E. grandis x E. urophylla. The strain Pseudomonas sp. PKE117 could be an alternative bioagent to replace the white-rot fungi in the biopulping of softwood. (C) 2007 Elsevier Ltd. All rights reserved.