Improvement of glucoamylase production for raw-starch digestion in Aspergillus niger F-01 by maltose stearic acid ester.

OBJECTIVES

To investigate the role of maltose stearic acid ester (MSAE) for improving raw-starch-digesting glucoamylase (RSDG) production by Aspergillus niger F-01 and its regulatory mechanism.

RESULTS

RSDG activity was enhanced 8.3-fold by adding 5 g MSAE to 1 l basal medium at the beginning of the culture. RSDG biosynthesis nearly ceased by adding 100 μg actinomycin D/ml or 50 μg cycloheximide/ml in a 48 h culture in the basal medium. RSDG biosynthesis was restarted by adding MSAE in the culture repressed by actinomycin D. No revival of RSDG synthesis was observed by adding MSAE in the culture repressed by cycloheximide.

CONCLUSIONS

MSAE improved RSDG production in A. niger by inducing the transcription of RSDG.