Bringing plant cell wall‐degrading enzymes into the lignocellulosic biorefinery concept

Recent decades have seen the growth of immense interest in lignocellulosic biomass conversion technologies. This interest is motivated by their huge potential for energy and bioproduct generation and reduced dependency on non‐renewable feedstocks, leading to improved air quality and reduced emission of greenhouse gases. It is in this context that the lignocellulose biorefinery concept arises. Among the lignocellulose conversion technologies available, enzymatic conversion has emerged as a promising candidate, since it represents a biomass management approach that integrates recycling and remediation in an environmentally friendly manner. Although already in existence, biorefineries employing enzymatic conversion of lignocellulose are at an incipient stage. There remain many operational difficulties, resulting in a very costly overall process that is reflected in product price, reducing market competitiveness. Therefore, much research is still needed to improve the operational and financial feasibility of this process. This paper covers general biorefinery concepts, as well as new and associated concepts, such as the circular economy, bioeconomy, and waste biorefinery. Subsequently, the global outlook, including examples of currently existing enzyme‐based lignocellulose biorefineries and their status, is described. The main technical and economic challenges are also discussed, and various potential tools for the optimization of biomass degradation in enzyme‐based biorefineries are presented. Finally, the future perspectives for the sector are considered, and models of the ideal biorefinery and globally integrated biorefinery hubs are proposed. These models may contribute to the future establishment of such biorefineries as competitive industries, consistent with the sustainable bioelectro economy paradigm.