**3.7 Optimum ratio of Pb-LPMO and Pb-ChiA during the hydrolysis of crystalline chitin**

To understand the effect of Pb-LPMO on the hydrolysis of crystalline chitin, we added 0.01–30 μM Pb-LPMO to the reaction solution containing 1 μM Pb-ChiA. (**Figure 5**). With increasing concentration of Pb-LPMO, the concentration of the hydrolysis products (GlcNAc and (GlcNAc)2) increased. When 1–10 μM of Pb-LPMO was added to the reaction mixture, products at higher concentration were obtained as compared with other concentrations. However, the addition of more than 10 μM Pb-LPMO decreased the concentration of the hydrolysis products in the reaction mixture. For efficient hydrolysis of crystalline chitin, addition of 3 μM Pb-LPMO to the reaction mixture containing 1 μM Pb-ChiA is optimal. The released products were approximately two-fold higher upon the addition of Pb-LPMO. Vaaje-Kolstad et al. reported that CBP21 (LPMO) strongly promotes hydrolysis of crystalline β-chitin by chitinase A and C from *S. marcescens* [23]. In this study, Pb-LPMO was found to efficiently promote hydrolysis of crystalline chitin.
