Strategies to reduce carbon and water footprints in lignocellulosic biorefineries towards net zero carbon emissions

Abstract

The successful deployment of lignocellulose biorefinery (LBR) has potential to address the global challenges including, environmental degradation, energy security, climate change and poverty eradication. Biorefineries of lignocellulosic biomass (LCB) provide a wide array of bioproducts through different means including biochemical, thermochemical and catalytic routes boosting circular economy. LCB, by virtue, is consisted of complex polysaccharides and lignin which contribute to high recalcitrance eventually requiring high energy, water, chemicals for its processing into biofuels, biochemicals and biomaterials. Because of diverse and complex processing routes, significant amounts of carbon and water footprints (CWFs) exerts in the biorefinery. Reducing CWFs in LBR is essential for the sustainable industrial practices. This review explores strategies to reduce the CWFs, which are the key to advancing biofuel and chemical production from LCB. This review presents a novel integrated analysis of strategies that simultaneously target CWFs, providing comprehensive framework that aligns with global decarbonization and sustainable resource management by investigating various unit operations in LBRs, starting with biomass pretreatment, enzymatic hydrolysis and proceeding to fermentation or catalytic conversion to product followed by downstream processing. Selection of eco-friendly and efficient processing routes, and considering the effective utilization of LCB including induction of 3Rs (reuse, reduce and recycle) can remarkably overcome the CWFs in LBRs. The article thoroughly examines the factors contributing to the CWFs and identifies key strategies for minimizing impacts on environment and natural resources, thus supporting the transition towards more environmentally-friendly and sustainable LBRs.