Immobilization ofAeromonas bivalviumPT2 Cells with Alginate and Measurement of Chitinolytic Activities

Abstract

Aeromonas bivalvium is one of the chitinolytic bacteria that able to degrade chitin into its derivatives. These bacteria can only be used once during the fermentation process, which is less profitable to be applied in industrial scale. This limitation can be solved by bacterial immobilization method. This study aimed to determine the effect of bacterial cell immobilization on chitinolytic activity and to determine the stability of the immobilized bacteria during repeated usage. Bacterial cell immobilization was carried out by entrapment method with 1% sodium alginate matrix. Immobilized bacteria was cultured in two different mediums, namely nutrient broth (NB) and nutrient broth (NB) added with colloidal chitin (NB + K). Tests for chitinolytic activity were carried out in bacteria. In addition, the stability of immobilized bacteria was also tested for chitinolytic activity with repeated removal and use. The result shows that the effectiveness of immobilization on average is 91.8%. Immobilization did not significantly affect chitinolytic activity when compared with bacteria without immobilization. Immobilized bacteria in this study has similar performance as bacteria without immobilization. The results of the stability tests including chitinase activity and NAG released indicated a significant decline during repeated usage with maximum usage of three times.