Lignocellulosic Materials Into Biohydrogen and Biomethane: Impact of Structural Features and Pretreatment

Abstract

Production of energy from lignocellulosic biomass or residues is receiving everincreasing interest. Among the different processes, dark fermentation for producing biohydrogen and anaerobic digestion for producing biomethane present considerable advantages. However, they are limited by the accessibility of holocelluloses which are embedded in the lignin network. This paper proposes a review of works on the conversion of biomass into biohydrogen and biomethane with the comprehensive description of i) biomass composition and features that may impact on its anaerobic conversion, ii) the impact of different kinds of pretreatment on these features and on the performance of biohydrogen and methane production.

Soybean Straw, Corn Stover and Sunflower Stalk as Possible Substrates for Biogas Production in Croatia: A Review

“…27,58 Pretreatment methods can be divided into different categories: mechanical, physical, chemical, biological and various combinations of these. 27,29,32 Further in the text, the most common pretreatment methods used for corn, soybean and sunflower harvest residues (or the residues similar to them according to the chemical composition) are discussed in more detail. To our knowledge, the AD of soybean straw and sunflower stalk has not been studied in detail so far.…”

“…30 Chipping, milling or grinding lead to the reduction of the particle size increasing the accessible surface area, reducing the degree of cellulose crystallinity and the degree of cellulose and hemicellu- *All values are shown on a total solids basis loses polymerization. 29,32 By breaking the large structures, the efficiency of the hydrolysis increases. 59 It is well documented that smaller particles are better digested in biogas production particularly if combined with some other pretreatment method.…”

“…Lignin is a major barrier in the lignocellulosic biomass bioconversion process. 29,32 Harvest residues could be a good source for AD, due to large availability of biomass. However, agricultural biomass like sunflower stalk, corn stover, and soybean straw contain complex structure of lignocellulose, and does not contain easily fermentable free sugars (Table 3).…”

“…Hemicelluloses have a lower molecular weight than cellulose and are more amorphous, random, and branched with little strength that makes it highly susceptible to biological, thermal, and chemical hydrolysis. 29,32 Lignin is the most complex polymer in nature. 27 It is a large and complex aromatic and hydrophobic amorphous heteropolymer consisting of three different phenylpropane alcohols: p-coumaryl, coniferyl and sinapyl, and their quantity varies according to species, maturity, and the space localization in the cell.…”

Screening of lignin-degrading fungi for their ability to decay cassava residue

“…Currently, cassava residue is mainly used as raw material for production of methane or protein feed. However, the bioconversion efficiency of cassava residue is low due to its recalcitrant lignocellulose structure [1,4]�� Hence, to improve the bioconversion efficiency of cassava residue, a promising method must be explored to decompose its lignocellulosic components, in particular the lignin component [5]. From the economic and environmental perspectives, fungal decay with lignin-degrading microorganisms has received great interest as an alternative to physical and chemical methods since it is a simple process and low energy requirement [6].…”