Bacterial biodegradation and bioconversion of industrial lignocellulosic streams

Abstract

Lignocellulose is a term for plant materials that are composed of matrices of cellulose, hemicellulose, and lignin. Lignocellulose is a renewable feedstock for many industries. Lignocellulosic materials are used for the production of paper, fuels, and chemicals. Typically, industry focuses on transforming the polysaccharides present in lignocellulose into products resulting in the incomplete use of this resource. The materials that are not completely used make up the underutilized streams of materials that contain cellulose, hemicellulose, and lignin. These underutilized streams have potential for conversion into valuable products. Treatment of these lignocellulosic streams with bacteria, which specifically degrade lignocellulose through the action of enzymes, offers a low-energy and low-cost method for biodegradation and bioconversion. This review describes lignocellulosic streams and summarizes different aspects of biological treatments including the bacteria isolated from lignocellulose-containing environments and enzymes which may be used for bioconversion. The chemicals produced during bioconversion can be used for a variety of products including adhesives, plastics, resins, food additives, and petrochemical replacements.

RETRACTED: Biodegradation of Endocrine-Disrupting Chemicals and Residual Organic Pollutants of Pulp and Paper Mill Effluent by Biostimulation

“…Lignin depolymerization by fungi has been reported for a variety of low molecular mass aromatic compounds of lignin degradation products, such as guaiacol, coniferyl alcohol, p -coumarate, ferulate, protocatechuate, p -hydroxybenzoate, and vanillate (Harwood and Parales, 1996; Masai et al, 2007). Benzoic acids are also used as value-added products, such as food preservatives (Mathews et al, 2015). Citral (3,7-dimethyl-2,6-octadienol), a type of terpenoid, has been detected in pulp and paper mill effluent under acidified conditions.…”

Effect of mechanical treatment on properties of cellulose nanofibrils produced from bleached hardwood and softwood pulps

“…On the other hand, the bleached hardwood contained higher hemicellulose content. These observations are in line with literature reports which show that softwoods are inherently associated with higher lignin contents while hardwoods are associated with higher percentages of polysaccharides (Betts et al 1997, Malherbe and Cloete 2002, Kiaei et al 2014, Mathews et al 2015. The high hemicellulose content is known for facilitation of disintegration of Eucalyptus pulp into nanofibrils and capable of reducing energy input during mechanical grinding (Iwamoto et al 2008, Syverud et al 2011.…”

Engineering of Corynebacterium glutamicum for Consolidated Conversion of Hemicellulosic Biomass into Xylonic Acid

“…Even though these previous approaches produced considerable amounts of xylonic acid from xylose, with competitive productivities and production yields, they all used purified xylose as a substrate. To acquire xylose from hemicellulosic biomass, however, enzymatic hydrolysis or chemical hydrolysis is also required, and this process costs substantial capital and time . In addition, most hosts used in previous reports utilize xylose as a carbon source for cell growth, so it was necessary to eliminate the xylose catabolic pathways in these hosts to minimize the loss of substrate .…”