Production and purification of a protease, a chitosanase, and chitin oligosaccharides by Bacillus cereus TKU022 fermentation

A protease-and chitosanase-producing strain was isolated and identified as Bacillus cereus TKU022. The protease and chitosanase were both produced using 1.5% (w/v) shrimp head powder (SHP) as the sole carbon/nitrogen source, and these enzymes were purified from the culture supernatant. The molecular masses of the TKU022 protease and chitosanase determined using SDS-PAGE were approximately 45 and 44 kDa, respectively. The high stability of the TKU022 protease toward surfactants, an optimal pH of 10 and an optimal temperature of 50-60 degrees C suggest that this high-alkaline protease has potential applications for various industrial processes. Concomitant with the production of the TKU022 chitosanase, N-acetyl chitooligosaccharides were also observed in the culture supernatant, including (GlcNAc)(2), (GlcNAc) 4, (GlcNAc) 5, and (GlcNAc)(6) at concentrations of 201.5, 12.4, 0.5, and 0.3 mu g/mL, respectively, as determined using an HPLC analysis. The chitin oligosaccharides products were also characterized using a MALDI-TOF mass spectrometer. A combination of the HPLC and MALDI-TOF MS results showed that the chitin oligosaccharides of the TKU022 culture supernatant comprise oligomers with degree of polymerization (DP) from 2 to 6. Using this method, the production of a protease, a chitosanase, and chitin oligosaccharides may be useful for various industrial and biological applications. (C) 2012 Elsevier Ltd. All rights reserved.