Impact and prospective of fungal pre‐treatment of lignocellulosic biomass for enzymatic hydrolysis

Abstract

The presence of lignin in lignocellulosic biomass leads to a protective barrier which prevents enzymes from being accessible to cellulose and hemicellulose for hydrolysis. As a result, pre‐treatment is a ‘must’ step for subsequent enzymatic hydrolysis. Bio pre‐treatment is normally conducted at low temperatures and low pressures without using expensive equipment, chemical agents, reactors, and additional energy for lignin removal and biomass structure destruction. Therefore, it is a green, safe, and inexpensive method. White‐rot fungi (WRF), a group of fungi (more than 1500 different species) are successfully applied in bioconversion processes such as sewage treatment, biopulping, conversion of forest and agricultural residues to animal feeds, and the production of edible or medicinal mushrooms. In the bio pre‐treatment process, WRF are mostly used for secreting ligninolytic enzymes, a variety of donor substrates and selective degradation of lignin. Current research related to WRF bio pre‐treatment is mainly focusing on the following four aspects: (i) selection of candidate strains for certain biomass materials; (ii) optimization of cultivation methods; (iii) characterization of fungal treated materials; and (iv) evaluation of combining bio pre‐treatment with chemical or physicochemical approaches. Future prospects and recommended research work on applying WRF in bio pre‐treatment are also briefly introduced and summarized in this review. These include (i) integrated methods (i.e. co‐treatment with organic solvents, diluted acids, supercritical CO2 and ionic liquids) to resolve problems existing in fungal pre‐treatment applications; (ii) mutation breeding and crossbreeding of fungal mycelia to obtain engineering strains; and (iii) integration of fungal pre‐treatment with simultaneous saccharification and fermentation to produce biofuels and value‐added products. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd

Study of the specific heat capacity of biomass from banana waste for application in the second‐generation ethanol industry

“…For the conversion of lignocellulosic biomass to biofuels, the first step is a pretreatment for the generation of sugar syrups from cellulose and hemicellulose [3]. The pretreatment methods can be roughly divided as follows: physical [4,5], physicochemical [6], chemical [7][8][9], biological [10], and electrical [11] methods, or a combination of these [12,13]. The chemical conversion pretreatment (espe-cially applied to the valorization of biomass under mild conditions) combined with the enzymatic saccharification of cellulosic biomass has been shown to be the most efficient method, showing vital results in the biofuel industry [14].…”

Study of the Ability of Reducing Saccharides to Chemically Transform Lignin

“…However, independently of the final application, a common problem is the obtaining of a cellulose pulp with high whiteness due to residual presence of lignin. Generally, the lignin is the most difficult to remove component [5] due to its complex structure, being a polymer comprised of variously linked phenylpropane units which are also responsible for the lignin chromaticity [6]. The dominant linkage between the units is the β-O-4 linkage.…”

Effect of surfactants on lignin modifying enzyme activity of Ganoderma species KX879638 and Lentinus species KY006984 under solid state fermentation

“…These fungi are efficient lignin degraders and possess a very efficient enzymes system consisting mainly one or more of the three families of extracellular and non-specific LMEs, lignin peroxidases (LiP), manganese peroxidases (MnP) and laccases (Lac) (Gianfreda and Rao, 2004). More than 1,500 species of white-rot fungi have been reported to decompose lignin with little consumption of cellulose (Tian et al, 2012), but only some of them for example Trametes, Phanerochaete, Pleurotus, Lentinus (Elisashvili et al, 2008), Ganoderma (Adaskaveg et al, 1990;D'Souza et al, 1999;Zhou et al, 2013), Phlebia (Vares et al, 1994;Hatakka et al, 2003) and Cerrena species HYB07 (Yang et al, 2016) have been reported to show high potential for production of LMEs.…”