Sustainable nitrogen-containing chemicals and materials from natural marine resources chitin and microalgae

Abstract Chitin and microalgae, naturally occurring nitrogen-rich marine resources, have vast applications in chemical production and material synthesis. Being undervalued and underutilized for a long time, marine biomass biorefinery has attracted considerable attention to realize its economic value in the last few years to meet the sustainable development requirements. This review first analyzes the chemical constituent of chitin and microalgae to understand their basic chemical properties. Next, various transformation pathways to value-added nitrogenous chemicals are summarized, and the biologically fixed nitrogen in marine biomass can be fully utilized with the reduced amount of energy-intensive synthetic NH3. Additionally, the biomass can also be used as precursors to synthesize functional N- doped carbon materials, which are potential candidates in catalysts, energy storage, and biomedical field. This review can provide insights into the fundamental understanding on the intrinsic nature and appropriate transformation options for N-rich marine biomass as renewable replacement of non-sustainable petroleum resources, and also disclose the nitrogen utilization from biomass for wider and more sustainable applications to enrich the chemicals production process.