Environmental chitinous materials as adsorbents for one-step purification of protease and chitosanase

We describe the use of chitinous materials as adsorbents for purification of protease and chitosanase from bromelain solution and chitosanase from culture supernatants of three bacterial strains: Serratia marcescens TKU011, Bacillus cereus TKU022 and Acinetobacter calcoaceticus TKU024. The best adsorption results were observed when crude shrimp shell chitin (CSSC) and 750-nm chitin nanoparticles (CNP) were used. The optimum temperatures for protease adsorption from bromelain solution (22.9 mg/mL) by CSSC (0.1 g) and by 750-nm CNP (0.1 g) were 4 and 25 °C, respectively. The purification folds of bromelain by CSSC and 750-nm CNP were 5.2 and 4.5, respectively. For purification of protease from culture supernatants of TKU011, 750-nm CNP was 4.0-fold better than CSSC. However, CSSC exhibited purification folds of 2.9 and 3.3 for the chitosanases from TKU022 and TKU024, respectively. The adsorbed chitinolytic enzymes TKU015 chitinase (30 kDa) and TKU024 chitosanase (27 kDa) exhibited high purity by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Thus, CSSC and 750-nm CNP indicate potential for use as tools for one-step purification of bacterial chitinolytic enzymes from culture supernatants.