Lignocellulolytic Enzymes in Biotechnological and Industrial Processes: A Review

Abstract

Tons of anthropological activities contribute daily to the massive amount of lignocellulosic wastes produced annually. Unfortunately, their full potential usually is underutilized, and most of the biomass ends up in landfills. Lignocellulolytic enzymes are vital and central to developing an economical, environmentally friendly, and sustainable biological method for pre-treatment and degradation of lignocellulosic biomass which can lead to the release of essential end products such as enzymes, organic acids, chemicals, feed, and biofuel. Sustainable degradation of lignocellulosic biomass via hydrolysis is achievable by lignocellulolytic enzymes, which can be used in various applications, including but not limited to biofuel production, the textile industry, waste treatment, the food and drink industry, personal care industry, health and pharmaceutical industries. Nevertheless, for this to materialize, feasible steps to overcome the high cost of pre-treatment and lower operational costs such as handling, storage, and transportation of lignocellulose waste need to be deployed. Insight on lignocellulolytic enzymes and how they can be exploited industrially will help develop novel processes that will reduce cost and improve the adoption of biomass, which is more advantageous. This review focuses on lignocellulases, their use in the sustainable conversion of waste biomass to produce valued-end products, and challenges impeding their adoption.

CAZyme prediction in ascomycetous yeast genomes guides discovery of novel xylanolytic species with diverse capacities for hemicellulose hydrolysis

“…Complete depolymerization of complex lignocellulosic polysaccharides requires a repertoire of enzymes that act together on the different chemical bonds [ 14 ]. While CAZyme systems from filamentous fungi and bacteria have been studied for decades, yeast species have received considerably less attention.…”

Biodegradation by Fungi for Humans and Plants Nutrition

“…The wood and the leaf litter biomass have mostly lignocelluloses as the major components produced by the plant photosynthesis and represent the most abundant renewable resource in the soil [11]. Lignocellulose is consists of three types of polymers, cellulose, hemicellulose, and lignin which are strongly linked together by chemical bonds like non-covalent forces and by covalent cross-linkage, very small amount of lignocellulose produced by-product in agriculture or used in industries, and the remaining are considered as residue [11,33]. Different microorganism degrades residue for the carbon as a source of energy, however, filamentous fungi evolved with the ability to degrade lignin to CO 2 and other compounds as discussed in the above paragraph [34].…”

A Review on Bacterial Contribution to Lignocellulose Breakdown into Useful Bio-Products

“…Also referred to as hydrolytic enzymes, they are of commercial importance as they make up a large part of the global enzyme market due to their rising use industrially and biotechnologically [ 50 ]. Apart from producing various hydrolytic enzymes, a number of microorganism are capable of producing several isozymes of the same enzyme [ 6 ]. The bacterial enzyme system when lignocellulose is degraded can be a non-complexed or complexed system synonymous with aerobic and anaerobic bacteria, respectively [ 51 ].…”

“…Anaerobic digestion involves conversion of biomass in the absence of oxygen and involves an array of microorganisms in different metabolic processes [ 123 , 124 ]. Hydrolysis is converting complex polymers to simpler amino acids and sugars by the action of hydrolytic enzymes which come from cellulolytic bacteria [ 6 ]. Temperature plays a huge role in the activity of hydrolysis.…”

“…They can be used in the sustainable production of useful chemicals, fuels [ 3 ], and renewable energy [ 4 ]. Studies have shown that lignocellulosic biomass can be broken down by contributions from several microorganisms [ 5 ] with manifold fungal and bacterial genera giving rise to cellulolytic and hemicellulolytic enzymes [ 6 ] under aerobic and anaerobic surroundings to achieve this [ 7 ]. The use of enzymes from microbial sources is being preferred to others because they are not difficult to nurture and manipulate for desired yields when compared to other sources [ 8 ].…”