Universiteit Leiden

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Research project

Regulation of enzyme production in fungal cell factories

Our object is to identify and characterize transcription factors involved in lignocellulosic biomass degradation in the filamentous fungus Aspergillus niger.

2014 - 2018
Arthur Ram
BE-Basic funded project within Flagship 10 - CSC scholarship to Jin BE-Basic funded project within Flagship 10 - CSC scholarship to Jin

Aspergillus niger is a fungus that naturally feeds on decaying plant tissue. Therefore, it is equipped with a high capacity to secrete biomass degrading enzymes. These enzymes are of industrial interest, because they can be employed in the production of biofuels and chemicals from lignocellulosic biomass feedstock.

Plants biomass is a complex structure composed of cell wall polysaccharides cellulose, hemicellulose and pectin, and storage polysaccharides starch and inulin. Black mold Aspergillus niger naturally secretes enzymes that degrade the complex structures in lignocellulosic biomass.

Enzyme secretion in A. niger is a tightly regulated process. In other words, A. niger secretes lignocellulosic biomass degrading enzymes only when they are needed. This regulation is executed by transcription factors, which are proteins that can bind to DNA and activate or repress the expression of the genes. Transcription factors involved in the regulation of pectin degrading enzymes have been not identified until now.

We aim to identify and characterize the transcription factors involved in the regulation of the plant cell wall biomass degrading enzymes. We will make use of gene deletion approach and DNA binding assay to identify the transcription factors. Target genes of the identified transcription factors will be revealed by genome-scale expression profiling. With the knowledge obtained, A niger strains with an increased yield of enzyme production will be created.

  • Alazi E, Niu J, Kowalczyk JE, Peng M, Aguilar Pontes MV, van Kan JA, Visser J, de Vries RP, Ram AF. The transcriptional activator GaaR of Aspergillus niger is required for release and utilization of D-galacturonic acid from pectin. FEBS Lett. 2016 Jun;590(12):1804-15. doi:10.1002/1873-3468.12211
  • Niu J, Alazi E, Reid ID, Arentshorst M, Punt PJ, Visser J, Tsang A, Ram AF. An Evolutionarily Conserved Transcriptional Activator-Repressor Module Controls Expression of Genes for D-Galacturonic Acid Utilization in Aspergillus niger. Genetics. 2017 Jan;205(1):169-183. doi: 10.1534/genetics.116.194050
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