Development of energy efficient nanocellulose production process by enzymatic pretreatment and controlled temperature refining of cotton linters

Nanocellulose (NC) is a new frontier subject of research owing to its unique material properties. The key challenge in producing the NC on commercial scale is high energy requirement in mechanical methods and high use of toxic chemicals in chemical methods. The present study aimed at development of a process protocol for energy-efficient production of NC from cotton linters. Four different production processes involving the chemical and enzyme pretreatments and mechanical processing such as beating, refining, Ultra-High Pressure Homogenization were studied. The cellulase enzyme (1%) pretreatment of cotton linters followed by controlled temperature refining (15 passes at 23 ± 5 °C) was found to be most efficient production process in terms of optimum size and less energy consumption. The NC obtained by this optimized process protocol had fibre diameter of 125 ± 25 nm and the energy consumption of the process was as less as 9.96 kWh/kg NC produced. The process involved 50–66% less energy requirement as compared to the reported average value of 20–30kWh/kg for NC production. NC produced from cotton linters using this optimized process protocol can find the application as a reinforcing agent in Kraft papers and biocomposite films to enhance their mechanical properties.