PURIFICATION AND CRYSTALLIZATION OF MICROBIAL XYLITOL FROM HYDROLYSATE OF LIGNOCELLULOSE USING MEMBRANE TECHNOLOGY

• Main Author: Qoharisma Salam, Wildan
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/64173
• Institution: Institut Teknologi Bandung

Xylitol is a sugar alcohol that could be used as a sweetener in food products. lts sweetness level is comparable to sucrose but has a much lower calorie and glycemic index. Xylitol could be produced through a biotechnological process by fermenting a xylose solution or hemicellulose hydrolyzate. The xylitol fermentation solution produced through the biotechnology process still has impurities that need to be separated. ln addition, xylitol is commercialized in the form of crystalline powder. Therefore, it is necessary to conduct downstream processing of the xylitol fermentation solution. Downstream processing is conducted using separation of impurities, concentrating the solution, and crystallization. Membrane distillation is performed to concentrating the xylitol fermentation solution, which does not require high temperature and energy and could be saved production costs. lt does not cause discoloration to the solution to be concentrated. ln addition, several studies show the potential of membrane distillation for the concentration of xylitol fermentation solutions in the xylitol crystal production process. Membrane distillation was performed using feed temperature at 70oC and a permeate temperature at 25oC with agitation in the feed tank. Furthermore, the crystallization process was conducted at room temperature (27oC) and chilling temperature (5oC) with variations of seeding. This study shows that membrane distillation could concentrate the xylitol fermentation solution to obtain xylitol crystals. Membrane distillation with agitation could minimize fouling, temperature polarization, and concentration polarization on the membrane, indicated by the minimum decrease in flux in every hour of the experiment. The feed that will be used for xylitol crystallization is membrane distillation retentate or supersaturated xylitol solution. However, the saturation concentration of xylitol solution at 50oC is 2 gram/ml. The best operating condition in the crystallization process is the chilling temperature (5oC) with 0.5% seeding that produced 71% of xylitol crystal.