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

Alternative black liquor recovery processes are presented in this chapter. Gasification processes (Manufacturing and Technology Conversion International fluidized bed gasification and Chemrec technology—atmospheric and pressurized system, catalytic hydrothermal gasification of black liquor), causticization processes (autocausticization and direct causticization), and the combination of alternative causticization and gasification processes are discussed. Environmental impact of black liquor gasification is also discussed.

Alternative Recovery Processes

Hemicellulose is the second-most abundant polysaccharide after cellulose and comprises about 25–30% of the lignocellulosic biomass. Xylans are the most abundant hemicelluloses. These are heteropolysaccharides with homopolymeric backbone chains of 1,4-linked β- d -xylopyranose units. In recent years, bioconversion of hemicelluloses has received much attention because of its practical applications in various agroindustrial processes. The xylose from the hemicellulose hydrolyzate can be fermented to ethanol, xylitol, lactic acid, furfural, and other valuable products by pentose-fermenting microbes. In this chapter, the conversion of xylose to ethanol, furfural, xylitol, 2,3-butanediol, organic acids, butanol, biohydrogen, chitosan, xylo-oligosaccharides, ferulic acid, vanillin, fermentation substrate for production of enzymes, and other value-added products are highlighted.

Products from Hemicelluloses

Contents: P. Bajpai/P.K. Bajpai: Realities and Trends in Enzymatic Prebleaching of Kraft Pulp * P.L. Rogers/H.S. Shin/B. Wang: Biotransformation for L-Ephedrine Production * A. Mukhopadhyay: Inclusion Bodies and Purification of Proteins in Biologically Active Forms * A.C. Ghosh/R.K. Mathur/N.N. Dutta: Extraction and Purification of Cephalosporin Antibiotics * D. Dochain/M. Perrier: Dynamical Modelling, Analysis, Monitoring and Control Design for Nonlinear Bioprocesses.

Biotreatment, downstream processing and modelling

The galloping rises in price of fibrous raw materials and waste disposal problems are leading paper producers throughout the world to increase their use of secondary fibers for paper products. The percentages of secondary fiber in almost every grade of paper and boards and particularly in printing and writing papers has more than doubled in the past decade, and is expected to triple or quadruple in the next 10–15 years. The huge secondary paper undertaking is primarily aimed at reducing volumes of wastepaper in the world's growing landfill sites. Since recycling has such an obvious environmental attachment, it follows that the processes used to produce deinked fibers, especially the bleaching process, should have come very much under inspection in recent years. Hydrogen peroxide is mainly used for bleaching of secondary fibers, at least during the last quarter century. However, various reducing agents and chlorine containing compounds have been also used. The pressure on modern secondary fiber mills to produce a chlorine-free product is now as strong as those directed toward virgin bleached kraft pulp mills. This is especially true considering that, in the United States and in other countries, the federal government and states and provinces are specifying secondary papers for use by their many branches of government.

Chlorine-free Bleaching of Secondary Fibers

The study deals with a novel technique for hardening and stabilization of Ca-alginate entrapped cell system for ethanol production. This method involves the treatment of Ca-alginate immobilized yeast cells with an inexpensive inorganic compound followed by a physical treatment. The treated beads have been used for the production of ethanol from cane sugar and molasses for six months in batch and continuous bioreactors

Pratima Bajpai

Papers

Alternative Recovery Processes

Products from Hemicelluloses

Biotreatment, downstream processing and modelling

Chlorine-free Bleaching of Secondary Fibers

Whole cell immobilization for high stability in ethanol production.