Energy saving with fungal enzymatic treatment of industrial poplar alkaline peroxide pulps J.C. Sigoillot a, *, M. Petit-Conil b , I. Herpoe ¨l a , J.P. Joseleau c , K. Ruel c , B. Kurek d , C. de Choudens b , M. Asther a a Unite ´ INRA de Biotechnologie des Champignons Filamenteux, IFR-BAIM, Universite ´s de Provence et de la Me ´diterrane ´e, ESIL, 163 Avenue de Luminy, Case Postale 925, 13288 Marseille cedex 09, France b Centre Technique du Papier, domaine universitaire, B.P. 7110, 38020 Grenoble Cedex, France c Centre de Recherches sur les Macromole ´cules Ve ´ge ´tales, domaine universitaire de Saint-Martin-d’He `res-Gie `res, 601 Rue de la Chimie, B.P. 53, 38041 Grenoble Cedex 9, France d Laboratoire de Physicochimie et Biotechnologie des Polyme `res, Institut National de la Recherche Agronomique, Moulin de la Housse, BP 1039, 51687 Reims cedex 2, France Received 10 August 2000; received in revised form 29 March 2001; accepted 23 April 2001 Abstract An alkaline peroxide industrial pulp from poplar was treated with a manganese peroxidase (MnP) from the hypersecretory strain of Phanerochaete chrysosporium I-1512 after a second stage of refining. The enzymatic treatment caused an improvement in the pulp quality by inducing an enzymatic refining onto the fibers. Transmission electron microscopy showed that the enzymatic refining was characterized by internal and external fibrillation of the fibers. Chemical modifications of lignin caused by MnP treatment facilitated the post-refining stage before papersheet manufacture. All together the enzymatic treatment resulted in energy savings of 25% during beating. © 2001 Elsevier Science Inc. All rights reserved. Keywords: Manganese peroxidase; Phanerochaete chrysosporium I-1512; Pulp and paper; Enzymatic refining; Poplar; Alkaline peroxyde 1. Introduction Mechanical pulps represent about 20% of the world pulp production. The mechanical pulping processes generate high yield pulps rich in lignin but with relatively low strength properties. Moreover, the manufacture of mechan- ical pulps are energy consuming. Considerable research has been devoted to improve mechanical pulp properties and to reduce the production cost of the process. In recent years, the use of white-rot fungi for treating wood chips before the refining stages to facilitate fiber separation and to reduce the refiner energy consumption has been developed [1–3]. Sev- eral reports have shown the effectiveness of biomechanical pulping process but the fungal treatments needed incubation times too long for an industrial scale application. In con- trast, enzymatic treatment which take only few hours are more compatible with mill processes. The effects of en- zymes on mechanical pulps depend largely on their pene- tration into the pulp. Ruel et al. [4] have shown that the action of ligninolytic enzymes such as manganese peroxi- dase (MnP) and laccase on high yield pulp fibers was more efficient after secondary pulp refining when the fiber struc- ture was deeply opened. The use of isolated enzymes in high-yield pulping processes was rather new. However some studies have already revealed the interest of the intro- duction of such a treatment in high-yield pulping processes. Sigoillot et al. [5] have shown that treatment of wheat straw chemimechanical (CMP) pulp with MnP enhanced the me- chanical properties of the pulp by a selective action of MnP on the lignin. A patent has been filed by Farell [6] for the use of lignin peroxidases to improve the optical properties and strength of mechanicals pulps. Recently, Pere et al. [7] demonstrated that a primary refined mechanical pulp treated with cellobiohydrolase gave energy savings of between 10 to 40% in the secondary refining stage without modifica- tions of the fiber length and paper strength. Consequently, alternative technology results in net savings in production costs. * Corresponding author. Tel.: +33-4-91-82-86-06; fax: +33-4-91-82- 86-01. E-mail address: jcs@esil.univ-mrs.fr (J.C. Sigoillot). www.elsevier.com/locate/enzmictec Enzyme and Microbial Technology 29 (2001) 160 –165 0141-0229/01/$ – see front matter © 2001 Elsevier Science Inc. All rights reserved. PII: S0141-0229(01)00368-4