Lignocellulose recalcitrance

Dye decolorizing potential of the WRF Ganoderma lucidum KMK2 was demonstrated for recalcitrant textile dyes. G. lucidum produced laccase as the dominant lignolytic enzyme during SSF of wheat bran, a natural lignocellulosic substrate. Crude enzyme shows excellent decolorization activity to anthraquinone dye Rema-zol Brilliant Blue R without redox mediator, whereas diazo dye Remazol Black-5 (RB-5) requires a redox mediator [43]. 

In cellulosic ethanol production processes, a pretreatment procedure is needed to disrupt the recalcitrant structure of the lignocellulosic materials so that the cellulose can be more efficiently hydrolyzed by cellulase enzymes [2], These pretreatments include physical, biological, and chemical ways, such as uncatalyzed steam explosion, liquid hot water, dilute acid, flow-through acid pretreatment, lime, ammonium fiber/freeze explosion, and ammonium recycle percolation [3, 4], Most of these methods involve a high temperature requirement, which is usually achieved through convection- or conduction-based heating. 

Due to the complex structure of lignocelluloses, the release of fermentable sugars is a hurdle for the industrialization of this renewable resource (Zhao et al., 2012a). The complex structure of plants functions as protection against microbial and enzymatic attacks and is called biomass recalcitrance (Himmel and Picataggio,... 

Taherzadeh MJ, Jeihanipour A. (2012). Recalcitrance of lignocellulosic biomass to anaerobic digestion. In Mudhoo A, editor. Biogas Production Pretreatment Methods in Anaerobic Digestion. Wiley Online Library, pp. 27-54. 

Zhao X, Zhang L, Liu D. (2012a). Biomass recalcitrance. Parti the chemical compositions and physical structures affecting the enzymatic hydrolysis of lignocellulose. Biofuels, Bioprvd Biorefin, 6, 465-482. 

Separation of biomass components is the very important initial step for the upcoming efficient utilization of biomass sources. Several physical and chemical separation methods are currently employed to overcome the recalcitrance of lignocelluloses. These methods include acid hydrolysis, alkaline hydrolysis, ammonia fiber expansion, hot water, organic solvent, and ionic liquid separation technologies. In this section of the chapter, all of the above separation methods are discussed. 

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