High-content screening of Aspergillus niger with both increased production and high secretion rate of glucose oxidase

Abstract

Objectives: To develop a rapid, dual-parameter, plate-based screening process to improve production and secretion rate of glucose oxidase simultaneously in Aspergillus niger.

Results: A morphology engineering based on CaCO₃ was implemented, where the yield of GOD by A. niger was increased by up to 50%. Analysis of extracellular GOD activity was achieved in 96-well plates. There was a close negative correlation between the total GOD activity and its residual glucose of the fermentation broth. Based on this, a rapid, plate-based, qualitative analysis method of the total GOD activity was developed. Compared with the conventional analysis method using o-dianisidine, a correlation coefficient of -0.92 by statistical analysis was obtained.

Conclusion: Using this dual-parameter screening method, we acquired a strain with GOD activity of 3126 U l^-1, which was 146% higher than the original strain. Its secretion rate of GOD was 83, 32% higher than the original strain.

Keywords: Aspergillus niger; Calcium carbonate; Dual-parameter screening; Glucose oxidase; Plate-based screening; Secretion rate.