Utilization of Plant Biomass for the Production of Renewable and Sustainable Biofuels With Zero Carbon Emission

Introduction

In the USA and around the globe, the public deliberations have grown increasingly concerned considering the impacts of global warming, calling on academics and industries for working rational to mitigate the effects of greenhouse gas emission (Cole et al., 1997; von Blottnitz & Curran, 2007). Many experts have expressed their anxiety considering the increasing costs and sustainability of fossil feedstocks reserve, with some expert people revealed that the global oil production has already notched, and the global energy consumption rate is constantly increasing (Hajjari et at., 2017; Nejat et al., 2015). Considering the issues for example, environmental and non-renewable energy with fossil feedstocks in particular with crude oil, a global biofuel technology needs to be implemented (Luque et al., 2008). Currently a considerable amount of agricultural edible-food residues such as corn, starch, sugar, and oil has been out-putted for the production of first-generation biofuels in North America, Brazil and Europe (Ruth, 2008). In Asia and other countries, a significant part of the productive land has been utilized for the cultivation of biofuels plants for example, palm oil. In order to fulfil the rising global requirement for the energy as biofuels and to reduce the reliance on fossil feedstocks and to also avoid the straining the global food supply, an integrated biorefinery must be processed to acquire the increasing amounts of renewable, sustainable and eco-friendly biofuels from plant biomass, including agriculture and forest residues, municipal waste, animal residues and dedicated bioenergy plants (Luque et al., 2008; Shabih et al., 2018).

For enhancing the anticipations of product portfolio of plant biomass-to-biofuels formation processes, it is vital to develop effective conversion technologies for the valorisation of abundant alternate lignocellulosic biomass into value added co-products. Lignocellulosic biomass is highly recalcitrant structure, assorted class of functional groups and decorated with a set of various linkages (Singh & Dhepe, 2016a, 2018). Plant biomass is mainly consisted of cellulose (homopolymer; C6 sugar), hemicellulose (heteropolymer; C5 and C6 sugars) and lignin (heteropolymer; C6 + C3, C4 or C5; phenolic propenoids) (Mosier et al., 2005; Singh, 2019). Several methods for example, chemical, physical, biological and thermal have been implemented for effective conversion of plant biomass into biofuels (Huber et al., 2006). Among all, the enzymatic process is more effective and remarkable in terms of selectivity for desire products, green process mostly avoid using the harmful chemicals, safe to handle compared to toxic, flammable and corrosive chemicals, etc. (Payne et al., 2015; Straathof, 2014). The current technologies used to produce the biofuels from edible sources are bioethanol and that is used in spark ignition engines (Alonso et al., 2010; Serrano-Ruiz et al., 2012). Bioethanol has good properties as a fuel, good for ignition engines, eco-friendly and easily producible at large scales (Balat, 2011; Vohra et al., 2014). Biofuels derived from plant biomass are called as a carbon neutral fuel or zero carbon emission (McMillan, 1997). Zero carbon emission means that the carbon dioxide emitted during the utilization of fuel, for example, in transport or electricity generation, etc. is reabsorbed by the plants during the photosynthesis (McMillan, 1997).