Highly efficient production of Aspergillus niger amylase cocktail by solid-state fermentation using triticale grains as a well-balanced substrate

Abstract

Triticale (x Triticosecale, Wittmack), an important industrial crop, with high grain yield, containing high amounts of starch, proteins and also major and minor mineral elements, is not yet sufficiently utilized. The simultaneous production of alpha-amylase and glucoamylase isoforms by Aspergillus niger on triticale grains, without any nutritive supplements, was developed, optimized and scaled up 10 fold for the first time. The specific combination of the examined effects led to the production of a novel glucoamylase isoform. Reduction of particle size, increase in oxygen availability and substrate height lead to an increase of 30 % in the production of amylases. Reduction of the relative humidity from 65 to 30 % increased glucoamylase production 2 fold and alpha-amylase production by 30%. The peak production of alpha-amylase (158 U g(-1)) and glucoamylase (170 U g(-1)) were obtained in Erlenmeyer flasks and in scaled-up trays. The obtained A. niger amylase cocktail was more efficient in raw starch hydrolysis from wheat flour, 29 % more efficient in glucose formation and 10 % more efficient in total reducing sugar formation, than the commercially available amylase cocktail SAN Super 240L, which is widely used in industry.