Emerging sustainable opportunities for waste to bioenergy: an overview

Energy is an essential building block for human welfare, socioeconomic development, and quality of life. Rapid urbanization, industrialization, and modernization are the major key factors behind the increase of energy demands in the last few decades. Some prominent issues like climate change, global warming, increased greenhouse gases, increasing/fluctuating fossil fuel costs, and high energy demands forced scientific community to explore alternative sources of energy. To meet the extensive pace of population explosion, industrialization, and pollution, the demand for alternative energy sources has gained prominence. The energy crisis and waste generation have catered the route of waste to energy for biofuels. Biofuels are composed of diverse fuels to serve economic and environmental sustainability, reduced dependency on imported petroleum fuels. The organic waste generated from households and industries is potent source for biofuels. Algal and yeast biomasses have achieved significant importance due to their high productivity rate, oil content, and absence of lignin. The lignocellulosic biomass has high productivity and can be used for biorefineries. The biofuels such as bioethanol, biodiesel, biogas, bioelectricity, and biohydrogen from wide range of substrates can serve the energy demand of the globe. The bioenergy for global transportation has further boosted research efforts. Investigating the use of these energy alternative sources is a key priority for most of the countries to meet the pledges to reduce greenhouse gas emissions. This chapter focuses on the different types of biomass transforming technologies for bioenergy from waste. The technology, prospects, and implementation are addressed. The emerging biochemical pathways (i.e., anaerobic digestion, alcoholic fermentation, extraction-transesterification, microbial fuel cell) for biofuels are described. Transesterification to produce biodiesel and waste to bioelectricity in microbial fuel cell are reviewed.