Sustainability assessment of selected biowastes as feedstocks for biofuel and biomaterial production by emergy evaluation in five African countries

Africa is a continent with enormous natural resources in the form of biomass and innovative ways are needed to exploit those ones available from agricultural processes and other production systems. This paper aims to assess the sustainability of a set of potential feedstocks for the production of biofuels and other value added products in Egypt, Ghana, Kenya, Morocco and South Africa. These feedstocks are residues from agricultural and industrial food processing systems that we assess by emergy evaluation for insights into their sustainability. The feedstocks are grouped into sugar-rich (corn stover, cassava peels, pineapple peels, olive oil pomace and rejected bananas) and nutrient-rich (cocoa pods, discarded cabbage leaves, cattle manure and soybean processing residues). Where possible, comparison is made between traditional and commercial production of the same good. Despite higher environmental impacts, commercial systems were found to perform better in exploiting natural resources. Finally, sugar-and nutrient-rich feedstocks were compared on the basis of glucan and ash content, respectively. Cassava peels and cattle manure gave the best performance from an emergy point of view. This approach enabled emergy evaluation of feedstocks that also considered their potential for the production of useful bioproducts. (C) 2015 Elsevier Ltd. All rights reserved.