Generation of antibacterial oligosaccharides derived from chitin using heterologous endochitinase synthesized in Escherichia coli

Aims: To synthesize two heterologous endochitinases in Escherichia coli and demonstrate their potential for applied use in generating antibacterial chitin-derived oligosaccharides (OGS). Methods and Results: Heterologous endochitinase genes, chiA Nima and chiA74, were expressed in E. coli. Endochitinases were secreted by the E. coli export machinery and by ∼20 h maximal chitinolytic activity was observed. The highest chitinolytic activity was observed with ChiA Nima, which produced antibacterial OGS with activities against Enterobacter cloacae, Escherichia coli, Staphylococcus aureus and S. xylosus. Conclusions: It was shown that the export machinery of E. coli is well suited for the secretion of bioactive ChiA74 and ChiA Nima endochitinases, and that the latter can generate antibacterial OGS. Significance and Impact of the Study: Our study suggests that it is feasible to synthesize endochitinases ChiA Nima and ChiA74 codified by E. coli and mass-produce these enzymes in culture supernatants. As signal peptides in native ChiA Nima and ChiA74 were recognized by the protein export molecular apparatus in E. coli, these short peptides could be included as signal sequences for transport in E. coli of other proteins with applied value. This is the first report suggesting that ChiA Nima can be used to produce OGS to control food-borne pathogenic bacteria.