Microcrystalline cellulose production from sugarcane bagasse: Sustainable process development and life cycle assessment

Sugarcane bagasse (SCB), a major and abundantly available byproduct of sugarcane processing industries is presently being used for energy generation. However, its rich resource content makes it a perfect feedstock for the production of various value-added products. In this communication, Microcrystalline Cellulose (MCC), a partially depolymerized cellulose is in vogue due to its versatile physical properties which holds substantial applications in the pharmaceutical industries, was produced from the surplus available SCB. Experiments were designed to optimize MCC production from SCB using three different chemical methods namely MCC1, MCC2 and MCC3 by varying the reaction conditions. Relatively higher yield of cellulose (0.34 g/g SCB) and MCC (0.32 g/g SCB) were observed with MCC2 method, followed by MCC3 (cellulose 0.32 g/g SCB; MCC 0.31 g/g SCB) and MCC1 (cellulose 0.30 g/g SCB; MCC 0.28 g/g SCB). Fourier transform infrared spectroscopy (FT-IR) showed good correlation with commercial grade MCC for the presence of characteristic functional groups. X-ray diffractograms (XRD) showed 79.8%, 84.1% and 87.4% crystallinity for MCC1, MCC2 and MCC3, respectively. The morphological analysis of all the three MCC samples correlated well with the standard MCC. EcoScale analysis awarded scores greater than 75 for the three MCC methods, in which MCC2 scored the maximum (84). Life cycle analysis depicted the impacts of MCC production methods on various environmental impact categories, where MCC3 method showed relatively less environmental impact in terms of global warming (27% less than MCC2). MCC3 further characterized with X-Ray Photoelectron Spectroscopy, Thermogravimetry analysis (TGA), Differential thermal analysis (DTA) and Differential scanning calorimetry (DSC) depicted its characteristic properties. Additionally, the sustainability analysis functioned as a valuable tool to assess the environmental impact of the process, prior to scaling up.