In a process/an apparatus for producing bleached cellulose in which a lignin- and cellulose-containing suspension is subjected to at least one process step for oxygen-assisted bleaching in a reactor, such as alkaline oxygen delignification, oxygen-enhanced extraction or oxygen-enhanced peroxide bleaching, the oxygen required for the oxygen-assisted bleaching is supplied to the reactor at least partially in the form of oxygen-containing nanobubbles. The small size and high stability of the nanobubbles allow uniform distribution of the oxygen in the suspension and a comparatively long exposure time. The efficiency of the bleaching is thus substantially increased.

The present invention relates to the removal of hemicelluloses from paper-grade alkaline pulp thereby upgrading the pulp e.g. into dissolving-grade pulp using a combination of enzyme treatment, hot caustic extraction and optionally one or more bleaching steps.

A method for producing mechanical paper pulp comprises: impregnating unprocessed wood, whereby unprocessed wood is exposed to an impregnating composition comprising at least a laccase enzyme and a formula mediator (I), wherein R.sub.1 and R.sub.2 are identical or different groups, chosen from among a hydrogen atom, a hydrocarbon chain, linear or branched, saturated or unsaturated, comprising 1 to 14 carbon atoms, wherein each hydrocarbon chain can be replaced by one or more functional groups chosen from among —OH, —SO.sub.3, benzyl, amino, mercapto, keto or carboxyl, wherein R.sub.1 and R.sub.2 in combination can form a cyclical structure, to achieve impregnation of the wood; and mechanically refining the impregnated wood, such that a mechanical paper pulp is obtained. The disclosure also relates to an impregnating composition used in this method and to the use thereof in a method for producing mechanical paper pulp, as well as to a method for producing paper.

In some embodiments, a method may include treating pulp. The method may include contacting a wood pulp with a singlet oxygen source. The method may include contacting the wood pulp with an alkaline peroxide source. The singlet oxygen source may include a peracetate oxidant solution and generating a reactive oxygen species. The peracetate oxidant solution may include peracetate anions and a peracid. In some embodiments, the peracetate solution may include a pH from about pH 10 to about pH 12. In some embodiments, the peracetate solution has a molar ratio of peracetate anions to peracid ranging from about 60:1 to about 6000:1. In some embodiments, the peracetate solution has a molar ratio of peracetate to hydrogen peroxide of greater than about 16:1. The peracetate oxidant solution may provide enhanced treatment methods of bleaching, brightening, and delignifying pulp fibers involving the use of peracetate oxidant solutions.

In some embodiments, a method may include treating pulp. The method may include contacting a wood pulp with a singlet oxygen source. The method may include contacting the wood pulp with an alkaline peroxide source. The singlet oxygen source may include a peracetate oxidant solution and generating a reactive oxygen species. The peracetate oxidant solution may include peracetate anions and a peracid. In some embodiments, the peracetate solution may include a pH from about pH 10 to about pH 12. In some embodiments, the peracetate solution has a molar ratio of peracetate anions to peracid ranging from about 60:1 to about 6000:1. In some embodiments, the peracetate solution has a molar ratio of peracetate to hydrogen peroxide of greater than about 16:1. The peracetate oxidant solution may provide enhanced treatment methods of bleaching, brightening, and delignifying pulp fibers involving the use of peracetate oxidant solutions.

A high efficiency bleaching method for cellulosic pulp includes: (a) providing a charge of aqueous cellulosic pulp to a bleaching vessel at a consistency of from 10% to 30% along with a peroxy bleaching agent and an alkaline agent effective to adjust pH of the charge to 9.5 to 12.5; and (b) bleaching the aqueous cellulosic pulp in the bleaching vessel while maintaining a bleaching temperature of from 110° F. (43° C.) to 135° F. (57° C.) and a pH of the charge from 9.5 to 12.5 for an extended bleaching retention time. The bleaching method is advantageously used to bleach low brightness recycle pulp, and/or as part of a multistage process with bleaching stages of lesser duration, and/or as a high peroxy efficiency, low dose bleaching process or in connection with concurrently storing and bleaching pulp.

A high efficiency bleaching method for cellulosic pulp includes: (a) providing a charge of aqueous cellulosic pulp to a bleaching vessel at a consistency of from 10% to 30% along with a peroxy bleaching agent and an alkaline agent effective to adjust pH of the charge to 9.5 to 12.5; and (b) bleaching the aqueous cellulosic pulp in the bleaching vessel while maintaining a bleaching temperature of from 110° F. (43° C.) to 135° F. (57° C.) and a pH of the charge from 9.5 to 12.5 for an extended bleaching retention time. The bleaching method is advantageously used to bleach low brightness recycle pulp, and/or as part of a multistage process with bleaching stages of lesser duration, and/or as a high peroxy efficiency, low dose bleaching process or in connection with concurrently storing and bleaching pulp.

A process for bleaching trichome fibers individualized from a trichome source, such as a leaf and/or a stem, is disclosed. The process of bleaching degrades trichome associated protein. Further, the bleaching processes improves the color of the trichomes.

A process for bleaching trichome fibers individualized from a trichome source, such as a leaf and/or a stem, is disclosed. The process of bleaching degrades trichome associated protein. Further, the bleaching processes improves the color of the trichomes.

The present invention relates to a method of treating biomass, comprising providing a lignocellulosic biomass feedstock; contacting the biomass feedstock in a mixture, which is formed by the biomass, water and an alkaline agent, with an oxidizing agent at an elevated temperature; and continuing the contacting of the biomass feedstock with the oxidizing agent until a notable part of the lignin is solubilised. The step of providing the biomass feedstock comprises contacting a biomass raw-material containing cellulose, hemicellulose and lignin in an aqueous phase with an alkaline agent; continuing the contacting of the biomass with the alkaline agent until a significant portion of the hemicellulose is dissolved in the aqueous phase to provide a modified biomass; recovering the modified biomass; optionally opening the structure of the modified biomass by mechanical treatment; and using the modified biomass as a lignocellulosic biomass feedstock. Treating the biomass provides hemicellulose, lignin and cellulose fractions that have a multitude of applications in the bioeconomy.