Roumanian Biotechnological Letters Vol. 13, No. 5, 2008, pp. 39143921 Copyright © 2008 Bucharest University Printed in Romania. All rights reserved Roumanian Society of Biological Sciences ORIGINAL PAPER 3914 Pretreatment by Ceriporiopsis subvesmispora and Phlebia subserialis of wheat straw and its impact on subsequent sodaAQ and kraftAQ pulping Received for publication, August 25, 2008 Accepted, October 5, 2008 SAIM ATES * , YONGHAO NI ** , CELIL ATIK *** , SAMI IMAMOGLU **** * Forest Products Engineering Department, Kastamonu University, 37200, Kastamonu, Turkey ** Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, NB, E3B6C2, Canada *** Forest Products Engineering Department Istanbul University, 80895, İstanbul, Turkey **** Forest Product Chemistry and Technology Department, Artvin Coruh University, 08000, Artvin, Turkey Corresponding author: saimates@gmail.com Abstract Pretreatments of wheat straw with two different lignindegrading fungal cultures  Ceriporiopsis subvesmispora and Phlebia subserialis were carried out and their effects on sodaAQ and kraftAQ pulping were studied. After two weeks of biotreatment of the wheat straw, both fungus were found to be suitable for biochemical pulping. The fungal pretreatment decreased the kappa number by as much as 24% and the unbleached pulp brightness increased by about 7% at a constant yield. Furthermore, the biopretreatment increased the brightness of the fully bleached pulp by about 1 ISO% point. This can apparently reduce the amount of the chemicals used in the bleaching process. The results on the sugar analysis of the pulps showed that in terms of carbohydrate composition, there were no significant differences between the biotreated and control pulps. However, the strength properties of the unbleached and bleached chemical straw pulps decreased slightly after the fungal pretreatment. This is different from reported results that the strength properties of mechanical pulps were improved after the fungal pretreatment. There was no difference of the two whiterot fungal species, Ceriporiopsis subvesmispora and Phlebia subserialis in term of their effect on the strength properties. Keywords: Wheat straw; Biochemical pulping; Ceriporiopsis subvesmispora; Phlebia subserialis; Pulp and paper properties; DEpD bleaching Introduction Today about 91% of the pulp and paper production in the world uses wood as the raw material, mostly in the developed countries. Environmental concern and short supply are increasing the pressure to use alternative sources for raw material in both developed and developing countries. The using of agricultural residuals in the pulp and paper industry has increased substantially. Agriculturebased fibers are particularly relevant in countries where demand for pulp and paper is increasing but the wood resources are limited [1]. Wheat straw is one of the most important agricultural residues. It is an annually renewable fiber resource that is available in abundant quantity in many regions of the world. Wheat straw could be considered as a natural fiber resource. Conventional pulping and bleaching methods used up to date have some disadvantages from the environmental aspects. The production of chemical pulps requires a large amount of chemicals that may have negative environmental impact. Mechanical pulping requires substantial amount of energy. Therefore, research on the development of alternative methods