Fig. 4

Analysis of hydrolysis products by HPLC. a The hydrolysis products of colloidal chitin with different concentration by recombinant ChiA for 12 h. 1: Standard of GlcNAc (peak a) and N, N′-diacetylchitobiose (peak b). 2–7: 10%, 15%, 25%, 30%, 35%, 40% colloidal chitin as substrate, respectively. b The hydrolysis products of N, N′-diacetylchitobiose by recombinant ChiA. 1: Standard of GlcNAc (peak a) and N, N′-diacetylchitobiose (peak b). 2, 3: The hydrolysis product of N, N′-diacetylchitobiose by recombinant ChiA at 0, 20 min, respectively. C The hydrolysis products of colloidal chitin by recombinant ChiA/BsNagZ. 1: Standard of GlcNAc (peak a) and N, N′-diacetylchitobiose (peak b). 2, 3: The hydrolysis product of colloidal chitin by recombinant ChiA for 12 h and then with recombinant BsNagZ for 0 (2), 20 min (3)