| In several tissues of Pomacea canaliculata, such as esophagus, stomach, liver and intestines, cellulase systems were found. The stomach juice of Ampullaria crossean was collected in order to purify cellulase. A cellulase, the molecular mass of which was 42.0kDa, was purified from the juice by 50% ammonium sulfate precipitation, Sephadex G-100 gel filtration column and Octyl-Sepharose CL-4B column chromatography. This enzyme is able to hydrolyze microcrystalline cellulose, carboxylmethyl cellulose sodium salt (CMC-Na) and xylan with the specific activities of 3.5, 34.2, and 177U/mg, respectively. It shows that this enzyme has activities of cellobiohydrolase, endo-p-l,4-glucanase and endo-β-l,4-xylanase. When hydrolyzing CMC-Na, microcrystalline cellulose and xylan, it reaches their maximum at 45℃, 50 ℃ and 50℃, respectively, and the favor pH ranges are pH 5.0-5.5, pH 5.5-6.0 and pH 5.5-6.0.Buffer solution was added to the entrails of the Ampullaria crossean, and then ground and centrifuged. The chitosan solution(1%) was added to the supernatant fluid with the percentage of 5. The mixture was centrifuged and the crude enzyme fluid was acquired. The yield of the CMCase was 95.5% after the chitosan flocculation. When hydrolyzing CMC-Na, microcrystalline cellulose, cellobiose and xylan, the specific activities of the crude enzyme fluid were 6.5, 0.31, 3.1 and 29.8U/ml, respectively. The crude enzyme solution was purified by Sephadex G-100 gel filtration column, when CMC-Na and cellobiose were used to trace the activities of the cellulase system. The result was that each of them had one activity peak. It showed that the activities of hydrolyzing cellulose in the tissues of Ampullaria crossean described above were from the same cellulase system. When this crude enzyme solution hydrolyzed the powder of straw, peanut pull and cornstalk, it reached their maximum at 40 ℃, 40℃ and 45℃, respectively. The abilities of degrading straw and cornstalk were higher than degrading peanut pull. |
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