Modification of regulators in Aspergillus niger to produce enzyme mixtures that completely degrade all available plant polysaccharides

Ref ID: 18320

Author:

Joost van den Brink, and Ronald P. de Vries

Author address:

CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT, Utrecht, The
Netherlands

Full conference title:

Asperfest 9

Abstract:

Plant biomass is a major substrate for many industries, such as food and feed, paper and pulp, and biofuel. Fungal enzymes from
Aspergillus niger have a long history of use in plant-biomass degradation. However, currently available commercial enzyme mixtures
are not sufficiently efficient for biofuel pretreatments. While in other applications only part of the biomass needs to be hydrolyzed,
complete hydrolysis of all available plant polysaccharides (i.e. cellulose, hemicellulose, and pectin) is required for cost-effective
biofuel production. The main reason for the absence of a suitable enzyme mixture is that enzyme production by A. niger is tightly
regulated by its environment. For instance, transcriptional regulator CreA is causing strong repression in the presence of easily
metabolisable carbon sources, such as glucose and xylose. Also, the activation of transcriptional activators such as XlnR, AraR, and
AmyR are necessary for the production of plant-polysaccharide degrading enzymes. In this project, we aim to modify the production
of biomass-degrading enzyme mixtures by genetic engineering of transcription factors in A. niger. For instance, initial results showed
that deleting CreA in combination with constitutive activation of XlnR enables production of cellulolytic and hemicellulolytic
enzymes on a wide variety of carbon sources. Importantly, enzymes are also produced during the initial and later culture phases.
Extending this strategy with other regulators is expected to generate enzyme mixtures that contain a broader range and higher level of
enzyme activities to achieve complete hydrolysis of all available plant polysaccharides.

Abstract Number: 71)

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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