Characterization, stability improvement, and bread baking applications of a novel cold-adapted glucose oxidase from Cladosporium neopsychrotolerans SL16.

Glucose oxidases are widely used in various industrial processes, including bread baking. In this study, a novel glucose oxidase gene, CngoxA, from Cladosporium neopsychrotolerans SL16, was cloned and expressed in Pichia pastoris. Recombinant CnGOXA exhibited maximal activity at 20 °C and pH 7.0, and was stable at 30 °C and pH 6.0-9.0 for 1 h, with a half-life of 15 min at 40 °C. Compared with CnGOXA, the half-life of its mutant CnGOXA-M1 (Y169C-A211C), at 40 °C increased approximately 48-fold, and was stable at 30 °C and pH 3.0-12.0 for 1 h. The kcat and catalytic efficiency of CnGOXA-M1 were enhanced 0.7- and 1.6-fold, respectively. Both enzymes were cold-adapted and highly resistant to SDS. Furthermore, CnGOXA-M1 had a more significant effect on bread volume than that of GOX from Aspergillus niger. These favorable enzymatic properties of CnGOXA-M1 make it a potentially useful enzyme for many industrial applications.