https://faculty.washington.edu/renatab/courses/PSE490/downloads/pretreatment.pdf

Features of promising technologies for pretreatment of lignocellulosic biomass.

Biofuels produced from various lignocellulosic materials, such as wood, agricultural, or forest residues, have the potential to be a valuable substitute for, or complement to, gasoline. Many physicochemical structural and compositional factors hinder the hydrolysis of cellulose present in biomass to sugars and other organic compounds that can later be converted to fuels. The goal of pretreatment is to make the cellulose accessible to hydrolysis for conversion to fuels. Various pretreatment techniques change the physical and chemical structure of the lignocellulosic biomass and improve hydrolysis rates. During the past few years a large number of pretreatment methods have been developed, including alkali treatment, ammonia explosion, and others. Many methods have been shown to result in high sugar yields, above 90% of the theoretical yield for lignocellulosic biomasses such as woods, grasses, corn, and so on. In this review, we discuss the various pretreatment process methods and the recent literature that...

http://ucce.ucdavis.edu/files/datastore/234-1388.pdf

Methods for Pretreatment of Lignocellulosic Biomass for Efficient Hydrolysis and Biofuel Production

Industrial applications of microbial lipases

Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept

Cellulases and related enzymes in biotechnology

The pulp and paper industry processes huge quantities of lignocellulosic biomass every year. The technology for pulp manufacture is highly diverse, and numerous opportunities exist for the application of microbial enzymes. Historically, enzymes have found some uses in the paper industry, but these have been mainly confined to areas such as modifications of raw starch. However, a wide range of applications in the pulp and paper industry have now been identified. The use of enzymes in the pulp and paper industry has grown rapidly since the mid 1980s. While many applications of enzymes in the pulp and paper industry are still in the research and development stage, several applications have found their way into the mills in an unprecedented short period of time. Currently the most important application of enzymes is in the prebleaching of kraft pulp. Xylanase enzymes have been found to be most effective for that purpose. Xylanase prebleaching technology is now in use at several mills worldwide. This technology has been successfully transferred to full industrial scale in just a few years. The enzymatic pitch control method using lipase was put into practice in a large-scale paper-making process as a routine operation in the early 1990s and was the first case in the world in which an enzyme was successfully applied in the actual paper-making process. Improvement of pulp drainage with enzymes is practiced routinely at mill scale. Enzymatic deinking has also been successfully applied during mill trials and can be expected to expand in application as increasing amounts of newsprint must be deinked and recycled. The University of Georgia has recently opened a pilot plant for deinking of recycled paper. Pulp bleaching with a laccase mediator system has reached pilot plant stage and is expected to be commercialized soon. Enzymatic debarking, enzymatic beating, and reduction of vessel picking with enzymes are still in the R&D stage but hold great promise for reducing energy. Other enzymatic applications, i.e., removal of shives and slime, retting of flax fibers, and selective removal of xylan, are also expected to have a profound impact on the future technology of the pulp and paper-making process.

Application of enzymes in the pulp and paper industry

Use of biotechnology in pulp bleaching has attracted considerable attention and achieved interesting results in recent years. Enzymes of the hemicellulolytic type, particularly xylan-attacking enzymes, xylanases are now used commercially in the mills for pulp treatment and subsequent incorporation into bleach sequences. The aims of the enzymatic treatment depend on the actual mill conditions and may be related to environmental demands, reduction of chemical costs or maintenance or even improvement of product quality. The use of oxidative enzymes from white-rot fungi, that can directly attack lignin, is a second-generation approach, which could produce larger chemical savings than xylanase but has not yet been developed to the full scale. It is being studied in several laboratories in Canada, Japan, the U.S.A. and Europe. Certain white-rot fungi can delignify kraft pulps increasing their brightness and their responsiveness to brightening with chemicals. The fungal treatments are too slow but the enzyme manganese peroxidase and laccase can also delignify pulps and enzymatic processes are likely to be easier to optimize and apply than the fungal treatments. Development work on laccase and manganese peroxidase continues. This article presents an overview of developments in the application of hemicellulase enzymes, lignin-oxidizing enzymes and white-rot fungi in bleaching of chemical pulps. The basic enzymology involved and the present knowledge of the mechanisms of the action of enzymes as well as the practical results and advantages obtained on the laboratory and industrial scale are discussed.

Biological bleaching of chemical pulps

Background and General Introduction -- Structure of Lignocellulosic Biomass -- Conversion of Biomass to Fuel -- Pretreatment of Lignocellulosic Biomass -- Summary of Biomass Pretreatment Methods -- Future Perspectives.

Pretreatment of Lignocellulosic Biomass for Biofuel Production

Publisher Summary The chapter introduces xylan as a major component of plant hemicellulose. It is the most abundant renewable polysaccharide in nature after cellulose. The chapter describes its structure and its interaction with plant cell walls. Due to the complex structure of xylans, several different enzymes are needed for their enzymatic degradation and modification. Properties and production of different enzymes—namely, xylanases, β-Xylosidases, α-Arabinosidases, α-Glucuronidases, and esterases are discussed in the chapter. Application of xylanases in pulp and paper making is reviewed in the chapter. The process involves some steps: prebleaching of kraft pulps, enzymatic debarking, fiber modification, production of dissolving pulp, removal of shives, and retting of flax fibers. The potential for use of xylanolytic enzymes in the food and feed industries is also high. The main aim in the application of xylanolytic enzymes is the hydrolysis of hemicellulosic substrate for production of fermentable sugars. The knowledge gathered on the hydrolysis mechanism of hemicelluloses, especially xylans, is greatly promoted the rapid application of these enzymes in new areas. Attention is focused on recent advances and on several aspects that were not covered in earlier reviews.

Pratima Bajpai

Papers

Application of enzymes in the pulp and paper industry

Biological bleaching of chemical pulps

Pretreatment of Lignocellulosic Biomass for Biofuel Production

Microbial xylanolytic enzyme system: properties and applications.

Eicosapentaenoic acid (EPA) production from microorganisms: a review.