Lignocellulosic materials, digestibility

Many factors influence the reactivity and digestibility of the cellulose fractions of lignocellulose materials. These factors include Hgnin and hemicellulose content, crystalhnity of cellulose, and the porosity of the biomass materials. Pretreatment of Hgnocellulosic materials prior to utiHzation is a necessary element in biomass-to-ethanol conversion processes. The objective of the pretreatment is to render biomass materials more accessible to either chemical or enzymatic hydrolysis for efficient product generation. The goals of the pretreatment are ... 

A Mechanism for Improving the Digestibility of Lignocellulosic Materials with Dilute Alkali and Liquid Ammonia... 

Thus, evidence is considerable that mild NaOH treatment of selected lignocellulosic materials increases the digestibility of their carbohydrate fractions. To know the maximum benefits possible from this treatment, it is helpful to know the mechanism for obtaining the improvement. 

Chemical Changes that Occur when Hardwoods Are Treated with Ammonia. Because the action of liquid NH3 on wood could be of interest for increasing the digestibility of lignocellulosic material, the work of Wang et al. (48) becomes pertinent. They showed that ammonolysis does occur, and determined the relative amount of nitrogen present as ammonium salts and as amide groups in ammonia-treated birch. 

The development of an economic process for increasing the digestibility of these lignocellulosic materials should provide for disposal—in a useful manner—of large quantities of coarse fibrous materials. This type of process would provide the medium through which these coarse unused plant tissues would be transformed into protein-rich food supplements for human consumption. 

Mechanical comminution of lignocellulosic materials beyond that achieved by animals tends to increase the digestion ceiling in vitro. This is illustrated by the percentage of the forage carbohydrate fermented... 

The main feature of anaerobic degradation of cellulose is the complex structure of the microbial communities, which form a specific food chain [99]. Due to its complexity, the organic compounds in lignocellulosic material were not fuUy degraded during the process [111, 112]. Hydrolysis can be the rate-limiting step for anaerobic digestion process in cases that the substrate was in particnlate form [113]. 

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