Circular economy aspects of lignin: Towards a lignocellulose biorefinery

Lignin is the second most abundant polymer, which comprises15-30% (dry weight) of total lignocellulosic biomass. Recent studies focused on the effective utilization of lignin biopolymer into a myriad of products such as lignin micro and nanocapsules, biosensors, platform chemicals, pharmaceutical compounds, biopolymers, electrodes in electrochemistry, re-useable adsorbent, resins and biodiesel production through oleaginous microbes. The development of eco-friendly and cost-effective techniques is need-of-the-hour, which can be addressed through the circular economy approach. In this review, the emphasis is laid on integrating bioethanol and biodiesel production and valorizing lignin into various useful products. Besides, prospects of lignin biorefinery coupled with economic policies to be deployed along with the practical implications, have been discussed. Adopting these new pragmatic technologies and policies enables not only the development of inexpensive technologies but also boosts the economic growth of lignocellulosic biorefinery.