Extraction and applications of lignin from bamboo: a critical review

Bamboo, commonly known as green gold, has various advantages like its quick proliferation, requires no irrigation, replanting is not necessary, can be grown without fertilizers, and can be easily harvested in 3–5 years. The primary chemical constituents of bamboo consist of lignin, cellulose, and hemicellulose. Its better properties and easy availability attract researchers and scientists globally to extract lignin from bamboo. Lignin has various unique characteristics, including biocompatibility, antioxidant, antimicrobial, redox activity, etc. Thus, it has opened a new field of research and development, having a laser-sharp focus on the lignin-derived advanced bio- and nanomaterials. This review highlights a detailed and comprehensive description of bamboo and lignin and discusses the successful utilization of bamboo for extracting lignin. Various researchers using different bamboo species to extract lignin are summarized. Mainly the culms of bamboo species like Neosinocalamus affinis, Bambusa rigida, Dendrocalamus brandisii, Pleioblastus amarus, Dendrocalamus sinicus, Gigantochloa scortechinii, Gigantochloa levis, and Phyllostachys edulis, were exploited to extract lignin. This review focused on the various chemical technologies used for lignin extraction like hydrothermal pretreatment processes, biochar-catalytic degradation, soda pulping extraction, microwave-assisted extraction, and ultrasonic-assisted extraction. A separate section is emphasized for materials perspective status and future work, which helps in featuring all the possible fields in which bamboo lignin widened the research paths. Thus, the review enables the global reader to ignite a deep sense of knowledge to create bamboo and lignin-based research innovation.