Genome-wide analysis of maltose utilization and regulation in aspergilli

Abstract

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, 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 illustrates 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 the carbon source is altered. Although the knowledge of 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.

Endocytosis of a maltose permease is induced when amylolytic enzyme production is repressed in Aspergillus oryzae

“…Reportedly, the predicted permease gene in this additional MAL cluster is upregulated in the presence of maltose (Vongsangnak et al, 2009). However, disruption of the predicted permease gene (AO090103000130) in the DmalP strain had no apparent effect on maltose consumption rate ( Supplementary Fig.…”

Uncovering transcriptional regulation of glycerol metabolism in Aspergilli through genome-wide gene expression data analysis

“…A. oryzae cultivations carried out on glucose are part of our published results in the report by Andersen et al (2008), A. niger batch fermentations on glucose are from the report of Vongsangnak et al (2009) and A. nidulans batch fermentations data on glucose and glycerol are from the report of Panagiotou et al (2008). Fermentations on glycerol with A. oryzae and A. niger were conducted speciWcally for this study under the conditions deWned in "Materials and methods".…”

Optimization of biomass production with enhanced glucan and dietary fibres content by Pleurotus ostreatus ATHUM 4438 under submerged culture

“…This phenomenon might be attributed to a special disaccharide consumption profile of the P. ostreatus strain, as it seems that there is high efficiency in the uptake of disaccharides by the using of effective sugar transporters within its metabolic mechanism. The validity of this assumption is relied by a similar observation with A. oryzae [38] that uses maltose permeases (MALT) to transport extracellular maltose into the cell and maltase (MALS) that hydrolyze intracellular maltose into glucose which is then channeled through glycolysis.…”