Sàng lọc chủng xạ khuẩn sinh tổng hợp chitinase từ rừng ngập mặn tỉnh Khánh Hòa và khảo sát điều kiện nuôi cấy để thu nhận chitinase

Abstract

Chitinase, a polysaccharide-hydrolyzing enzyme, serves as a crucial tool for characterizing the properties and biological functions of chitin oligosaccharides. Recently, chitinases derived from actinobacteria have received research interest due to their high activity and stability. In this study, 45 actinobacteria strains isolated from mangrove forests in Khanh Hoa Province, Vietnam, were screened for their ability to produce chitinase. The results showed that 41 strains (91.1%) exhibited enzymatic activity, with strain A41 demonstrating the highest chitin-degrading capacity, forming a hydrolysis zone of 21.50 ± 0.55 mm. Molecular identification based on 16S rRNA gene sequencing confirmed that strain A41 belongs to Streptomyces thermocarboxydus, showing 99.93% sequence similarity compared with the 16S rDNA gene database on GenBank. Optimization of culture conditions revealed that chitinase production by strain A41 reached a maximum activity of 3.39 ± 0.01 U/mL after 5 days of incubation in SCB medium supplemented with 1% sucrose and 0.5% malt extract. These findings highlight Streptomyces thermocarboxydus A41 as a promising actinobacterial strain for chitinase production with potential applications in medicine, agriculture, and environmental biotechnology.

Keywords: Chitinase enzyme, actinobacteria, mangrove forest, culture conditions.