This study highlights the recent advances in the treatment and value addition of lignocellulosic wastes (LCW) with main focus on domestic and agro-industrial residues. Mechanical, physical and biological treatment systems are brought into perspective. The main value-added products from lignocellulosic wastes are summarized in a manner that pinpoints the most recent trends and the future directions. Physicochemical and biological treatment systems seem to be the most favored options while biofuels, biodegradable composites and biosorbents production paints a bright picture of the current and future bio-based products. Engineered microbes seem to tackle the problem of bioconversion of substrates that are otherwise non convertible by conventional wild strains. Although the main challenge facing LCW utilization is the high costs involved in treatment and production processes, some recent affordable processes with promising results have been proposed. Future trends are being directed to nanobiotechnology and genetic engineering for improved processes and products. The paper presents state of the art review of the dual advantage of handling LCW for cleaner environment and production of renewable bio-products.

https://www.ajol.info/index.php/ajb/article/download/60134/48385

Recent advances in pretreatment of lignocellulosic wastes and production of value added products

Biofuels are promoted in a wide-scale as a means of achieving energy security and reducing greenhouse gas emissions. Biofuels derived from lignocellulosic biomass, particularly from agricultural crops are being massively supported worldwide for meeting multiple strategy objectives such as climate change mitigation, energy security and development of the rural economy. Recently, the negative implications of using food crops for fuel have been realized to possess a significant threat towards global food security and competition for arable land. In contrast, lignocellulosic biomass in the form of waste residues from agriculture, forestry and energy crop systems are geographically abundant worldwide and have the potential to support the sustainable production of liquid transportation fuels. This paper encompasses the improvement in biofuels sector in relation to revitalizing and restraining the rural economies across the globe along with the global statistics for lignocellulosic biomass availability. In addition, the socio-environmental impacts of energy and greenhouse gas emissions from biomass conversion technologies have been addressed through highlights on life-cycle assessment of several biomasses.

An assessment on the sustainability of lignocellulosic biomass for biorefining

This reviews aims to provide an insight and update of the state of biogas technology research in some selected sub-Saharan African countries in peer reviewed literature. This paper also aims to highlight the sub-Saharan countries’ strengths and weaknesses in biogas research and development capacity. An attempt is made to pinpoint future research in critically reviewing the biogas technology research. The methane-producing potential of various agriculturally sourced feedstocks has been researched, as has the advantages of co-digestion to improve carbon-to-nitrogen ratios and the use of pretreatment to improve the hydrolysis rates. Some optimisation techniques associated with anaerobic digestion including basic design considerations of single or two-stage systems, pretreatment, co-digestion, environmental conditions within the reactor such as temperature, pH, buffering capacity have been attempted in some of the researches in Nigeria, Tanzania, and Zimbabwe. However, there appears to be little research in biogas technology in many sub-Saharan African countries in internationally peer reviewed literature. Biogas production from large quantities of agricultural residues, animal wastes, municipal and industrial wastes (water) appears to have potential as an alternative renewable energy for many African countries if relevant and appropriate research is carried out to adopt the biogas technology to the local conditions in African countries. African scientists are urged to carry out research in biogas technology to locally demonstrate the feasibility, application, and adaptation of this technology and help improve the quality of energy supply in their respective countries.

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Biogas technology research in selected sub-Saharan African countries – A review

Biorefinery approach for cassava-based industrial wastes: Current status and opportunities

The feasibility of producing biofuels and biochemicals from lignocellulosic biomass via the biochemical platform depends largely on advances in pretreatment and hydrolysis technologies to obtain sugars from the cellulose and hemicelluloses of plant cell walls. This paper provides an overview of the merits and challenges related to developing biological pretreatment processes to modify lignin for facilitating subsequent enzymatic extraction of sugars. Although it has so far attracted little attention due to many inherent limitations, biological pretreatment has multiple benefits. Compared with extensively studied thermochemical processes, biological pretreatment is more environmentally benign, requires less energy, results in fewer inhibiting compounds and has potential to produce more co-products. Increasing understanding of termites and fungal systems has provided insights for developing more effective pretreatment technologies to realize these benefits. Specifically, this paper reviews the knowledge on ...

Biological pretreatment of lignocellulosics: potential, progress and challenges

Value addition of cassava and cassava wastes is necessitated by rapid post-harvest spoilage, deterioration, low protein content and environmental pollution caused by the effluent and the other associated wastes that poses aesthetic nuisance. Biogas plants of all sizes and varying levels of technical sophistication not only recover the energy contained in cassava wastes but also eliminate most of the animal and human health problems associated with contamination. Studies have shown the technical feasibility and nutritional desirability of converting carbohydrates and their residues into products containing a large amount of protein by means of microorganisms. Wastes transformation offers the possibility of creating marketable value-added products. There exists a great potential in the use of microorganisms such as fungi for the production of high quality feedstuffs from the abundantly available agro-industrial wastes, particularly carbohydrate residues. Cassava wastes can be processed and converted into value-added components such as methane (biogas), pig meat, ethanol, surfactant and fertilizer etc. Attention is now focused on the by-products of the anaerobic decomposition of the waste that takes place in a biodigester, which are the liquid fraction called biol and the solid fraction or biosol, which are excellent fertilizers for a variety of crops. The present review addresses the progress that has been made in each of these aspects with emphasis on the advantages of biol and biosol fertilizers.

	 

	Key words: Carbohydrate residue, waste transformation, biofertilizers.

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A. O. Ubalua

Papers

Cassava wastes: treatment options and value addition alternatives.