Chemical stability of a cold-active cellulase with high tolerance toward surfactants and chaotropic agent

• Surfactants were not able to reduce CelE1 activity significantly.
• CelE1 was found to be promising candidate for use as detergent additives.
• Chemical unfolding of CelE1 was very nearly completely reversible.
• Chemical unfolding of CelE1 proceeds as a two-state process.

CelE1 is a cold-active endo-acting glucanase with high activity at a broad temperature range and under alkaline conditions. Here, we examined the effects of pH on the secondary and tertiary structures, net charge, and activity of CelE1. Although variation in pH showed a small effect in the enzyme structure, the activity was highly influenced at acidic conditions, while reached the optimum activity at pH 8. Furthermore, to estimate whether CelE1 could be used as detergent additives, CelE1 activity was evaluated in the presence of surfactants. Ionic and nonionic surfactants were not able to reduce CelE1 activity significantly. Therefore, CelE1 was found to be promising candidate for use as detergent additives. Finally, we reported a thermodynamic analysis based on the structural stability and the chemical unfolding/refolding process of CelE1. The results indicated that the chemical unfolding proceeds as a reversible two-state process. These data can be useful for biotechnological applications.