Integrated lignocellulosic biorefinery: Gateway for production of second generation ethanol and value added products

An increasing demand for energy and depleting petroleum sources has elevated the need for producing alternative renewable resources. Owing to the prominence of lignocellulosic biomass as bio-renewable and the most abundant resource on Earth, this critical review provides perceptions into the potential of lignocellulosic biomass for production of second generation (2G) ethanol and value added products in a biorefinery manner. The efficient utilization of all three components of lignocellulosic biomass (i.e., cellulose, hemicellulose and lignin) would play a significant role in the economic viability of cellulosic ethanol. The pretreatment method is the key to the success of bioconversion processes and greatly influences the economics of biorefinery process. Biotechnology tools and process engineering play pivotal roles in development of integrated processes for production of biofuels, biochemicals and biomaterials from lignocellulosic biomass. Although, lignocellulosic biorefinery has ample scopes, commercial production of biofuels and chemicals is still challenging. In this context, this review entails concept of lignocellulose biorefinery, latest developments in 2G ethanol production process, importance and market potential of 2G ethanol as renewable fuel and value added chemicals, integration of processes, challenges for integrated production of fuel together with value added chemicals and future directions.