Purification and biochemical characterization of a cellulase from the digestive organs of the short-spined sea urchin Strongylocentrotus intermedius

Abstract

We isolated a cellulase from the digestive organs of the short-spined sea urchin Strogylocentrotus intermedius using a combination of ion-exchange chromatography and gel filtration together with an assay for carboxymethylcellulase activity. The isolated cellulase was stained as a single band by Congo red. The molecular weight of the isolated cellulase, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, was 59 kDa. The isolated cellulase exhibited hydrolytic activity toward carboxymethyl cellulose, with an optimum temperature and pH of 30 °C and pH 8. 0, respectively. The thermal stability of the enzyme was characterized by determining the temperature at which activity decreased by 50 % with treatment for 30 min at pH 7. 0 and found to be 32 °C. Cellulase activity remained at a high level at 5-20 °C, which is the growth temperature of the short-spined sea urchin. These results confirm that the short-spined sea urchin should preferably be reared at a water temperature of <20 °C. © 2012 The Author(s).