In vitro degradation of chitosan by bacterial enzymes from rat cecal and colonic contents

The degradative activities of extracellular and cell-associated portions of rat cecal and colonic enzymes, whose activities are comparable to that in the human colon, against five chitosan samples were characterized. The effects of the molecular weight (MW) and degree of deacetylation (DD) of chitosan on its susceptibility to degradation were investigated. In addition, the degradation function of rat bacterial enzymes was compared to that of a commercially available almond emulsinβ-glucosidase that contains a chitinase. The results show that rat bacterial enzymes had the ability to degrade chitosan with extracellular enzymes exhibiting a more profound effect than did cell-associated enzymes. The reaction to bacterial enzymes degradation was dependent on both the MW and DD of the chitosan sample. Those samples with a lower MW and lower DD were more susceptible substrates. A similar degradation function of rat bacterial enzymes and of almond emulsin β-glucosidase on chitosan was revealed, which indicates that almond emulsin β-glucosidase might be able to be used as an in vitro enzyme system to predict the large intestinal degradation of chitosan.