The actinobacterium Streptomyces cyaneus CECT 3335 was evaluated for its ability to delignify spruce wood chips (Picea abies) after 2 weeks of incubation prior to refiner mechanical pulping. Weight loss of the chips during the treatment ranged from 2% to 3%. Chemicalanalysis of the treated wood showed an increase in acid-soluble lignin content concomitant with a notable increase in the acid/aldehyde+ketone [AC/(AL+KE)] ratio of the lignin compared with the control. Structural alterations in wood cell walls were observed by optical and scanning microscopy using astra blue-safranin staining and cryosections stained with gold/palladium, respectively. A gradual loss of lignin from the lumen towards the middle lamella and incipient defiberization could be observed. The estimation of specific energy for the defibration and refining stages of treated pulp showed a 24% reduction in the energy required, largely due to a 30% saving in the defibration of chips. The analysis of handsheets obtained from treated pulp showed a notable improvement in some strength properties, such as breaking length, tear index and stretch. In addition, the high Gurley air resistance value indicates more packing of the voids of the fiber network. These results demonstrate for the first time the suitability of Streptomyces cyaneus for biomechanical pulping purposes.
- biomechanical pulping
- handsheet properties
- saving energy
- spruce wood chips
Hernandéz, M., Hernandéz-Coronado, M. J., Pérez, M. I., Revilla, E., Villar, J. C., Ball, A. S., Viikari, L., & Arias, M. E. (2005). Biomechanical pulping of spruce wood chips with Streptomyces cyaneus CECT 3335 and handsheet characterization. Holzforschung, 59(2), 173-177. https://doi.org/10.1515/HF.2005.027