Physiological characterisation of <Emphasis Type="Italic">acuB</Emphasis> deletion in <Emphasis Type="Italic">Aspergillus niger</Emphasis> |
| |
Authors: | Susan Meijer Willem Adriaan de Jongh Lisbeth Olsson Jens Nielsen |
| |
Institution: | 1.Center for Microbial Biotechnology,DTU-BioSys,Lyngby,Denmark;2.Sandoz GmbH,Kundl,Austria;3.Department of Chemical and Biological Engineering,Chalmers University of Technology,Gothenburg,Sweden |
| |
Abstract: | The acuB gene of Aspergillus niger is an ortholog of facB in Aspergillus nidulans. Under carbon-repression conditions, facB is repressed, thereby preventing acetate metabolism when the repressing carbon source is present. Even though facB is reported to be repressed directly by CreA, it is believed that a basal level of FacB activity exists under glucose-repressive
conditions. In the present study, the effect of deletion of acuB on the physiology of A. niger was assessed. Differences in organic acid and acetate production, enzyme activities and extracellular amino and non-amino
organic acid production were determined under glucose-repressing and -derepressing conditions. Furthermore, consumption of
alternative carbon sources (e.g. xylose, citrate, lactate and succinate) was investigated. It was shown that AcuB has pleiotropic
effects on the physiology of A. niger. The results indicate that metabolic pathways that are not directly involved in acetate metabolism are influenced by acuB deletion. Clear differences in organic acid consumption and production were detected between the ∆acuB and reference strain. However, the hypothesis that AcuB is responsible for basal AcuA activity necessary for activation of
acetate metabolic pathways, even during growth on glucose, could not be confirmed. The experiments demonstrated that also
when acuB was deleted, no acetate was formed. Therefore, AcuB cannot be the only activator of AcuA, and another control mechanism has
to be available for activating AcuA. |
| |
Keywords: | AcuB deletion Signal transduction pathways Organic acids Acetate |
本文献已被 SpringerLink 等数据库收录! |
|