Genome-wide analysis of maltose utilization and regulation in aspergilli

Artikel i vetenskaplig tidskrift, 2009

Maltose utilization and regulation in aspergilli is of great importance for cellular physiology and industrial fermentation processes. In Aspergillus oryzae, maltose utilization requires a functional MAL locus, each composed of three genes: MALR encoding a regulatory protein, MALT encoding maltose permease and MALS encoding maltase. Through a comparative genome and transcriptome analysis we show that the MAL regulon system is active in A. oryzae while it is not present in Aspergillus niger. In order to utilize maltose, A. niger requires a different regulatory system that involves the AmyR regulator for glucoamylase (glaA) induction. Analysis of reporter metabolites and subnetworks illustrate the major route of maltose transport and metabolism in A. oryzae. This demonstrates that overall metabolic responses of A. oryzae occur in terms of genes, enzymes, and metabolites when altering the carbon source. Although the amount of knowledge on maltose transport and metabolism is far from being complete in Aspergillus spp., our study not only helps to understand the sugar preference in industrial fermentation processes, but also indicates how maltose affects gene expression and overall metabolism.