ABSTRACT
The production of biofuels such as bioethanol using renewable biomass feedstocks has gained momentum in the recent decade; particularly, the use of cyanobacterial biomass for bioethanol production has received significant attention. This is mainly due to the advantages, such as comparatively easy processing as compared to the lignocellulosic crops and their production not competing with crop-based global food production. This chapter focuses on the key aspects and different approaches to bioethanol production using cyanobacteria biomass as feedstock. The conversion of cyanobacterial biomass to bioethanol can be carried out using three different methods, viz., conventional fermentation, which involves hydrolysis and fermentation of feedstock using microorganisms such as yeast and bacteria; dark fermentation; and photofermentation (involves genetically engineered cyanobacteria). Each of these methods has its own pros and cons; however, the use of genetically engineered cyanobacteria for bioethanol production via photofermentation has received scientific attention and has been introduced at an industrial scale. Biochemical and genetic engineering approaches have proved promising in improving bioethanol yield and productivity. Synechocystis is the most exploited cyanobacterial genus that has shown greater potential for biochemical and genetic engineering towards improved bioethanol yield and productivity through different routes. Technoeconomic assessment studies on bioethanol production using cyanobacterial feedstock, mainly conducted on genetically modified strains, have emphasized the need of integration of the bioethanol production with the production of coproducts and/or the use of waste sources for biomass production for improving the feasibility of this technology.
