Performance and economical evaluation of rotary peeling veneer from logs fermented by lactic acid bacteria: A low-cost, green log pretreatment method

Pretreatment is an efficient log softening method for enhancing the surface quality and properties of rotary peeling veneers. Traditional pretreatment methods such as hydrothermal and chemical pretreatment have problems of water and chemical pollution and high energy consumption. Therefore, this paper explored a simple and green biological pretreatment method by fermenting poplar logs with lactic acid bacteria. The microstructure, chemical structure, contents and physical properties of veneers from fermented logs with different fermented time and strain were systematically investigated. The microstructure of the veneer illustrated that the cell wall exhibited a smooth fracture, and the pore diameter of the pits on the vessel wall increased. The chemical structure of the veneers was stable and cellulose crystallinity showed a little change. The chemical contents were slightly degraded, resulting in a decrease in the pH value. However, these slightly degradation had no obvious effect on tensile strength of the veneers. The water absorption and surface brightness of the veneers were increased by 30.5 % and 3.5 % respectively, while the surface roughness was decreased by 66 %. The rotary peeling veneers fermented by the mixed strains for 14 days obtained ideal surface brightness and roughness. This log fermentation method not only has no water pollution, but also the fermentation solution can be recycled without additional energy consumption. Furthermore, the economical evaluation showed that this is an effective new, environmentally friendly and low-cost log pretreatment method for veneer production. • Poplar logs were fermented by different lactic acid bacteria and time to make veneer. • Microscale and chemical change mechanism of peeling veneer was characterized. • The surface quality of veneer was enhanced dramatically with mix strain of 14d.