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

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 °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 μg/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.