Abstract: The present invention aims to provide cellulose-based fibrous materials for obtaining papers and sheets having low density, high surface quality, good size stability despite of high strength, and high opacity. Cellulose-based fibrous materials having external fibrils consisting of an assembly of scale-like microfibrils exhibit a higher fiber stiffness, a lower water retention value and a higher specific surface area as compared with fibrous materials having filamentous external fibrils at the same freeness. Papers and sheets having low density, high surface quality, good size stability and high opacity can be obtained by using such fibrous materials.

Abstract: The first invention aims to provide a method for preparing stiffer bulky pulp at a freeness level comparable to that obtained by mechanical treatments to improve the bulkiness of product paper by searching for a method capable of adjusting freeness while suppressing damage to pulp fibers and internal fibrillation in a process for producing pulp. The second invention aims to strip contaminants deposited on pulp fibers and/or inorganic particles to reduce adhesion of the contaminants and decrease microorganisms in a treatment of process water containing long pulp fiber fractions used in a process for producing pulp and paper, thereby clarifying process water and thus preparing high-quality pulp and paper.

Abstract: Pulp bleaching method using SKB-1152 strain which is a lignin-degrading strain having high lignin degrading activity and pulp bleaching activity, or the culture produced using the SKB-1152. When the SKB-1152 strain of this invention or the culture produced using the same is to bleach pulp, the same bio-bleaching method as in the prior report may be used and there is no need for any special culture conditions. The SKB-1152 strain of the invention can be collected from decolorized areas formed in a culture rue medium which contains, lignin and/or pulp containing residual lignin, and being inoculated with a isolating source sample and cultured.