Isolation and characterization of microcrystalline cellulose from rice straw

Abstract

This research work is based on process optimization of extraction of microcrystalline cellulose in Sri Lankan facilities. The extraction consists of two main steps that are isolating chemically purified cellulose from rice straw of BG352 rice species and extracting microcrystalline cellulose from cellulose. Grinding, dewaxing, delignification, bleaching, acid hydrolysis, centrifugation, dialysis, sonication and freeze-drying are the basic procedures in this extraction process. Grinding, purification processes, acid hydrolysis and sonication was performed as per the records of optimized procedures in the literature. Centrifugation and dialysis were optimized in this study. The optimum process parameters for centrifugation were 8000rpm of centrifugation speed, 20°C of centrifugation temperature, 40 minutes of centrifugation time and the dialysis were 28 °C of dialysis temperature and 4 days of dialysis time for 12-14 kDa molecular weight cutoff membrane. Testing and characterization were performed after each procedure using Scanning Electron Microscope, X-ray diffractometer, Laser particle analyzer, Fourier Transform Infrared microscope as apparatus and ImageJ, Origin as software for result analyzing. And the study successfully achieved the aspects of extracting chemically purified microcellulose yielding 18.68% of harvest with 70.25% of crystallinity index, extracting cellulose fibers of 5.445μm in average diameter.