VALORISATION OF SORGHUM BIOMASS INTO SUSTAINABLE, HIGH-PERFORMANCE CELLULOSE NANOMATERIALS

摘要

The rise of biomass-derived nanocellulose addresses sustainability criteria demanded of new materials -renewability, abundance, biodegradability, and recyclability - which have been widely overlooked in the plastics era. Cellulose nanofibres (CNF) have conventionally been extracted from wood products, supported by an established forestry infrastructure, but the drive for biomass sustainability has encouraged researchers to explore non-wood sources over the past 15 years. Agricultural residues have emerged as a promising alternative due to their abundance, fast generation, and low starting value. In addition, their favourable biochemical composition eases the chemical and mechanical intensity required during biomass pulping and nanofibrillation. Sorghum is one of the most drought-resistant agricultural crops grown around the world, with years of research conducted to understand and improve its drought tolerance~1. While 1.0-2.7 Mt of sorghum grain are produced in Australia per annum~2, the majority of the non-grain biomass is channeled into low-value applications, such as livestock feed and bedding, soil fertilisation, or low yield fuel~3. Despite the isolation of CNF from many agricultural residues, most commonly involving cotton, bamboo, empty palm fruit bunch, sugarcane, and rice, sorghum-derived CNF has never been reported within literature~4. We hypothesize that the arid-adapted genetic architecture of sorghum will contribute towards material sustainability from multiple angles; by reducing water and fertilizer demand during growth, improving land utilisation due to its growth on marginal land, as well as reducing chemical and energy consumption during processing5. This project constitutes the foremost investigation into the biochemical, morphological, and material properties of sorghum-derived cellulose nanofibres. Using a phenotypically-distinct panel of eight sorghum varieties, and a comprehensive statistical framework bridging agronomy to material engineering, we address fundamental questions relating plant physiology to CNF properties. This includes assessing which sorghum varieties and plant sections produce the most sustainable and high performance cellulose nanomaterials.