Fungi in Consolidated Bioprocessing of Lignocellulosic Materials
Second generation biorefineries are based on the efficient exploitation of the carbon stored in lignocellulosic biomass. Many fungal genera have the capacity to enzymatically degrade lignocellulose, while other can transform the resulting degradation prod
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Fungi in Consolidated Bioprocessing of Lignocellulosic Materials Anastasia P. Galanopoulou and Dimitris G. Hatzinikolaou
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Industrial Approaches in Biomass Conversion—An Introduction
Over the last 30 years, lignocellulose biotechnology has made solid steps toward its transformation from a laboratory research topic to an industrial process of favorable financial perspective. The major driving force for this was the growing concerns over the emergence of the first generation biofuel technology. Since this approach mainly involved the exploitation of sucrose and starch derived sugars as its main substrates, it rapidly created a competition for land and water that were traditionally used for food production (Sims et al. 2010; Ho et al. 2014). Lignocellulosic biomass (LCB), on the other hand, is a renewable carbon source that predominantly comprises of agricultural and forestry residues and by-products, uniformly produced in large quantities throughout the biosphere. As a result, it appears as an ideal alternative for exploitation, through novel and efficient technologies cumulatively incorporated into the “2nd generation biorefinery” concept (Rowlands et al. 2008; Adsul et al. 2011; Dugar and Stephanopoulos 2011). The carbon stored in lignocellulosic biomass is distributed among three general types of polymers, namely: cellulose, hemicellulose, and lignin. These polymers are strongly interconnected with practically all types of chemical bonds, to yield a three-dimensional superstructure of high chemical recalcitrance (http://www.nature. com/scitable/content/structure-of-lignocellulose-14464273). In order to use lignocellulose as raw material for microbial transformations, it has to be broken down into soluble sugars and low molecular weight compounds. The b-1,4-glycosidic bond that is dominant in cellulose and hemicellulose structures, is among the most stable bonds in nature, and its chemical decomposition requires very harsh conditions A.P. Galanopoulou D.G. Hatzinikolaou (&) Microbial Biotechnology Group (MBG), Department of Biology, National and Kapodistrian University of Athens, 15784 Attica, Athens, Greece e-mail: [email protected] © Springer International Publishing Switzerland 2016 D. Purchase (ed.), Fungal Applications in Sustainable Environmental Biotechnology, Fungal Biology, DOI 10.1007/978-3-319-42852-9_11
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of high temperature and extreme pH values. Controlled enzymatic hydrolysis following mild chemical pretreatment, appears as the only sustainable and environmentally benign alternative for biomass degradation (Alvira et al. 2010; Naik et al. 2010; Van Dyk and Pletschke 2012). The enzymes required for biomass degradation have been isolated from a variety of species that expand throughout the tree of life and range from simple prokaryotes to insects and crustaceans (Cragg et al. 2015). A large variety of these enzymes has been isolated, characterized, and systematically categorized (www.cazy.org). From a practical point of view, exploitable quanti
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