Lignocellulosic biomass has been
widely considered as a renewable
source for bioproducts and bioenergy production via various biorefinery
techniques. Much effort has been taken for the valorization of carbohydrate
compositions (cellulose and hemicellulose). Until recently, lignin
has started to gain increasing attention as a renewable source that
can be valorized to high-value products. It has unique advantages
including low-cost, flexible modifiability, and wide compatibility
that can be used for diverse purposes. The valorization of lignin
into novel nanomaterials is a recent research endeavor that promises
opportunities to increase the overall economy of conventional biorefineries,
thus promoting the development of a circular bioeconomy, while its
suitability for nanomaterial preparation and application is significantly
related to its sources. To support the successful integration of conventional
biorefineries and lignin nanomaterial preparation and utilization,
this review first identify major biorefineries which produce lignin
as byproducts, summarizes major preparation and applications of lignin,
and then raises considerations and suggestions on the suitability
of different lignin sources for nanomaterial preparation and application.
Finally, some key challenges and perspectives are proposed for advancing
the integration of lignin nanomaterials production and conventional
biorefineries toward near-complete valorization of lignocellulosic
biomass.