Comparison of the Chitosan Degradation through Hydrothermal and Sonication-Hydrothermal Processes

摘要

Chitosan is a natural substance that has many applications in the fields of pharmacy and medicine. Because it has\udhigh molecular weight and does not dissolved easily in a neutral pH solution, then there is an effort to\uddepolymerize chitosan into low molecular weight chitosan and oligomers. Nowdays, one of the methods used to\uddegrade biomass is hydrothermal. Hydrotermal is one method of biomass degradation and polymers that is quite\udeffective and environmentally friendly. Because chitosan has strong hydrogen bonds in addition to high\udmolecular weight, it is necessary to treat chitosan by sonication before subjected to hydrothermal process. This\udstudy will compare degrading chitosan by only hydrothermal process and also sonication–hydrothermal\udprocesses. The hydrothermal of chitosan was carried out using a stainless steel tube reactor of 4-mL capacity at\ud200 °C for 4 s under pressures of 25 MPa for both of hydrothermal systems. For sonication– hydrothermal\udprocesses, chitosan was treated with sonication at 40 o\udC for 30 and 120 min before subjected to hydrothermal\udprocess. After hydrothermal, chitosan was characterized by viscosimetry and HPLC to determine molecular\udwight and also the dissolved product. Based on the product yield of the process, the sonication (40 °C,120 mins,\ud1 %)-hydrothermal process (200 °C, 4 mins) was the best process on this study and gave lactose yield as much as\ud90 %.