Objectives Chitinases play important role in chitin bioconversion, while few of them have been put into use due to their poor properties. We aimed to identify and characterize chitinases suitable forN-acetyl chitooligosaccharides (COSs) production from chitin materials. Results A chitinase gene (SsChi28) fromStreptomyces sampsoniiXY2-7 was cloned and heterologously expressed inE. coliBL21 (DE3) as an active protein. The deduced protein shared high sequence identities and structure similarities with some glycoside hydrolase family 19 chitinases. The recombinant enzyme (SsChi28) was purified and biochemically characterized. SsChi28 was a monomeric protein with a molecular mass of 30 kDa estimated by SDS-PAGE. It was most active at pH 6.0 and 55 degrees C, respectively, and stable in a wide pH range of 3.5-11.5 and up to 60 degrees C. The enzyme exhibited strict substrate specificities towards ethylene glycol chitin (222.3 U/mg) and colloidal chitin (20.1 U/mg). Besides, it displayed lysozyme activity againstMicrococcus lysodeikticus.SsChi28 hydrolyzed colloidal chitin to yield mainlyN-acetyl chitobiose, accounting high up to 73% (w/w) in total products. Conclusion The excellent enzymatic properties of SsChi28 may make it potential in chitin bioconversion (especially forN-acetyl COS production), as well as in biological control of fungal diseases.