Biorefinery processes to produce biofuels and functional materials from sugarcane bagasse: an update

The Australian sugarcane industry produces approximately 5 million dry tonnes of bagasse as a sugar production by-product. Sugarcane bagasse has been extensively studied for producing cellulosic biofuels, such as ethanol, as alternatives to fossil fuels. For cellulosic biofuel production, dilute acid pretreatment is commonly used to deconstruct lignocellulosic biomass, such as sugarcane bagasse, followed by enzymatic hydrolysis of pretreated biomass to produce fermentable sugar as glucose. Although some commercial-scale cellulosic ethanol plants have been established in some countries, the economics of cellulosic biofuels is still in doubt due to the high production cost and low fuel price. In addition, cellulosic biofuel production only uses the sugar resources (cellulose and hemicellulose), leaving large amounts of residual biomass, approximately 30–40% of the starting biomass, as a waste. Conversion of the residual biomass, which mainly consists of lignin and undigested carbohydrates to other value-added products, such as biochars and activated carbon, has the potential to maximise the value of sugarcane bagasse, and as a result, to increase the process economics. In this paper, a biorefinery process concept, which is based on dilute acid pretreatment and aims to produce both cellulosic biofuels and functional materials, is introduced. In addition, QUT’s research progress in developing such a biorefinery process is summarised. Key words Sugarcane bagasse, biofuel, biorefining, carbon, adsorption, energy storage