Efficient Production of Oligomeric Chitin with Narrow Distributions of Degree of Polymerization Using Sonication-Assisted Phosphoric Acid Hydrolysis

Abstract A method of producing oligomeric chitin using sonication-assisted phosphoric acid hydrolysis was introduced. The processing was continuous and scalable. Oligomeric chitin fractions with narrow distributions of degree of polymerization were obtained by differential precipitation using ethanol as precipitating agent at different ethanol-to-phosphoric-acid-solution volume ratios. The yield of oligomeric chitin with degree of polymerization between 4 and 10 was ≈30 % (mass fraction). The content of each fraction was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI TOF MS). Changes in chemical composition of oligomeric chitin was negligible, as verified by MALDI TOF MS, Fourier-transform infrared, and nuclear magnetic resonance spectroscopy. This new method for producing oligomeric chitin molecules is rapid, cost-effective, and safe.