Process Biochemistry, Vol.51, No.12, 2001-2010, 2016
Effect of glucose as a carbon repressor on the extracellular proteome of Aspergillus niger during the production of amylases by solid state cultivation
In comparison to traditional submerged cultivations, solid state cultivation (SSC) has been shown to reduce the effect of carbon catabolite repression during the production of important industrial enzymes, such as amylases. Nevertheless, the effect of a carbon repressor on the entire secretome during the production of enzymes of industrial interest has not been described. Therefore, the secretome composition and amylase production from Aspergillus niger grown in SSC using media containing starch and different concentrations of glucose (60 and 120 g/L) were evaluated. The results showed that proteins without an amino-terminal signal peptide, which is necessary for secretion through the classical secretory pathway, were detected at high glucose concentrations; some of these proteins were moonlighting proteins associated with pathogenesis. High concentrations of glucose also produced better amylase volumetric activities. alpha-Amylase activity was eight times higher in media containing glucose as compared to the medium containing only starch. Glucoamylase activity was 29 and 20 times higher at glucose concentrations of 60 and 120 g/L, respectively, compared to the medium containing only starch. Moreover, the presence of glucose had a variable effect on the abundance of the amylase isoforms produced by A. niger. (C) 2016 Elsevier Ltd. All rights reserved.
Keywords:Aspergillus niger;Respirometry;Secretome;alpha-amylase;Glucoamylase;Solid state cultivation