Vigilancia Tecnológica

Graphical Abstract and Lay SummaryChitosanase could hydrolase the ??1,4?linkages in partly N?acetylated chitosan and release chitooligosaccharides (COSs) or glucosamine. COSs have excellent water?solubility and various bioactivities, which provide a great potential in medical, pharmacological and industrial applications. In this study, chitosanase (CsnA) from S. coelicolor A3(2) M145 was secretory expressed in Pichia pastoris GS115. The secreted recombinant enzyme was purified and its function were verified. The potentials of CsnA as well as the COSs to act as antifungal agents were evaluated. AbstractIn this study, a glycoside hydrolase family 46 chitosanase from Streptomyces coelicolor A3(2) M145 was firstly cloned and expressed in Pichia pastoris GS115 (P. pastoris GS115). The recombinant enzyme (CsnA) showed maximal activity at pH 6.0 and 65°C. Both thermal stability and pH stability of CsnA expressed in P. pastoris GS115 were significantly increased compared with homologous expression in Streptomyces coelicolor A3(2). A stable chitosanase activity of 725.7 ± 9.58 U mL?1 was obtained in fed?batch fermentation. It's the highest level of CsnA from Streptomyces coelicolor expressed in P. pastoris so far. The hydrolytic process of CsnA showed a time?dependent manner. Chitosan oligosaccharides (COSs) generated by CsnA showed antifungal activity against Fusarium oxysporum sp. cucumerinum (F. oxysporum sp. cucumerinum). The secreted expression and hydrolytic performance make the enzyme a desirable biocatalyst for industrial controllable production of chitooligosaccharides with specific degree of polymerization, which have potential to control fungi that cause important crop diseases.