A new chitinase-D from a plant growth promoting Serratia marcescens GPS5 for enzymatic conversion of chitin

[Display omitted] •Characterized a new single modular chitinase, SmChiD from Serratia marcescens GPS5.•Without accessory binding domains SmChiD hydrolyzed polymeric chitin substrates.•SmChiD exhibited chitobiase and transglycosylation activity on chitooligosaccharides.•Transglycosylation activity of SmChiD can be used for synthesis of long chain CHOS.•Chitobiase activity of SmChiD can be used for producing GlcNAc from polymeric chitin. The current study describes heterologous expression and biochemical characterization of single-modular chitinase-D from Serratia marcescens (SmChiD) with unprecedented catalytic properties which include chitobiase and transglycosylation (TG) activities besides hydrolytic activity. Without accessory domains, SmChiD, hydrolyzed insoluble polymeric chitin substrates like colloidal, α- and β-chitin. Activity studies on CHOS with degree of polymerization (DP) 2–6 as substrate revealed that SmChiD hydrolyzed DP2 with a chitobiase activity and showed TG activity on CHOS with DP3–6, producing longer chain CHOS. But, the TG products were further hydrolyzed to shorter chain CHOS with DP1–2 products. SmChiD with its unique catalytic properties, could be a potential enzyme for the production of long chain CHOS and also for the preparation of efficient enzyme cocktails for chitin degradation.