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Lignin is the 3rd most abundant biopolymer surpassed by cellulose and hemicellulose and is the most abundant aromatics resource available on earth for utilization by mankind. It was considered undesirable historically which was usually burned as inefficient fuel. Lignin's 3D recalcitrant nature caused hinderance to feasible biorefinery of holocellulosic fraction of biomass; however, with the rise of lignin biorefinery the concept has changed completely. Now modern biorefinery of biomass insists on making complete value of all the streams including lignin by valorising into variety of phenolics, biopolymers and other high value-added chemicals. Biological depolymerisation of lignin via enzymes is environmentally benign and preferred approach by virtue of low chemical requirement and disposal and energy demand; however, economic challenges are ahead. Robust enzymes are available in nature which can either modify or depolymerise lignin to add further value. Lignin modifying as well as lignin degrading auxiliary enzymes are instrumental and pave the way to a green process for lignin valorisation. This review article is focussed on various lignin degrading as well as lignin modifying enzymes produced by microorganisms especially fungi for degradation or modification of lignin, and its mechanisms, along with the strength and challenges for sustainable bio-based economy development.
木质素是仅次于纤维素和半纤维素的第三大最丰富的生物聚合物，并且是地球上可供人类利用的最丰富的芳香族资源。它被认为是不可取的历史上，通常是作为低效燃料燃烧。木质素的3D可降解性质对生物质的全纤维素部分的可行生物炼制造成了阻碍;然而，随着木质素生物炼制的兴起，概念已经完全改变。现在，现代生物质生物炼制坚持通过将各种酚类化合物、生物聚合物和其他高附加值化学品增值，使包括木质素在内的所有物流发挥全部价值。通过酶对木质素进行生物解聚是环境友好的，并且由于化学要求和处置以及能量需求低而成为优选的方法;然而，经济挑战就在前面。在自然界中可获得稳健的酶，其可以改性或解聚木质素以增加进一步的价值。 木质素改性以及木质素降解辅助酶是有用的，并且为木质素价值的绿色过程铺平了道路。本文综述了微生物特别是真菌产生的各种木质素降解酶和木质素改性酶对木质素的降解或改性作用及其机理，并沿着了生物经济可持续发展的优势和挑战。