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 evaporation of black liquor is presented in this chapter. Different types of evaporators–rising film evaporators, falling film (FF) evaporators (plate-type FF evaporator, tubular-type FF evaporator), forced circulation evaporators are discussed. Multiple-effect evaporation, production of black liquor of high solids, other methods used for concentration of black liquor, modern evaporation, scaling and scale control, evaporator troubleshooting instrumentation, and process control and other operations which may take place in the evaporator area are also discussed.

Evaporation of Black Liquor

Purification of xylanases is usually based on the multistep series of nonspecific techniques. Xylanase purification schemes have generally used standard column chromatographic techniques, mainly ion exchange and gel filtration, but also hydrophobic interaction. The low molecular weight of certain xylanases has also enabled their separation from other proteins using ultrafiltration. Furthermore, adsorptive interactions of certain low-molecular-weight xylanases (20 kDa) with gel-filtration resin matrices cause these enzymes to elute as proteins smaller than 12 kDa. The various purification schemes have successfully isolated a number of apparent xylanases from Trichoderma sp. to electrophoretic homogeneity. For application on pulp fibers, the purification of xylanases does not have to be complete as long as cellulase activity is eliminated. Various strategies for preparing cellulase-free xylanases have been reviewed. Ultrafiltration can be used in conjunction with solvent exchange through ion exchangers to produce high yields of cellulase-free xylanase. One of the most important steps in purification of extracellular xylanases is clarification. Microbial xylanases are mainly purified by chromatographic methods. Precipitation with ammonium sulfate and ethanol has been used in the maximum purification studies as the initial step.

Purification of Xylanases

Cultivation of yeasts from the prehydrolysate from a rayon pulp mill

Kraft Spent Liquor Recovery

This chapter discusses the dramatic growth over the past few years that have been exhibited in oxygen delignification or oxygen bleaching. The terminology depends on where the line is drawn between pulping and bleaching. Oxygen delignification in the pre-bleaching stages decreases the kappa number before chlorination and therefore, the effluent load emanating from the bleach plants is reduced. Oxygen delignification involves an extension of the delignification started in the cooking process and provides the bleaching plant with a pulp that has a considerably reduced kappa number. The primary advantages of oxygen delignification coupled with modified bleaching over conventional bleaching include: the partial replacement of chlorine-based chemicals (especially chlorine gas) for elemental chlorine-free pulp production, the elimination of all chlorine-based chemicals in total chlorine-free sequences, the retainment and the recycling of the extracted organics and chemicals applied in the oxygen stage, the incineration of the recycled organics to generate energy, and the energy savings. This technology is more selective than most extended delignification processes, but may require significant capital investment to implement.

Pratima Bajpai

Papers

Evaporation of Black Liquor

Purification of Xylanases

Cultivation of yeasts from the prehydrolysate from a rayon pulp mill

Kraft Spent Liquor Recovery

Options for environmentally benign bleaching