Abstract
The interest in the conversion of plant biomass to renewable fuels such as bioethanol has led to an increased investigation into the processes regulating biomass saccharification. The filamentous fungus Aspergillus niger is an important microorganism capable of producing a wide variety of plant biomass degrading enzymes. In A. niger the transcriptional activator XlnR and its close homolog, AraR, controls the main (hemi-)cellulolytic system responsible for plant polysaccharide degradation. Sugarcane is used worldwide as a feedstock for sugar and ethanol production, while the lignocellulosic residual bagasse can be used in different industrial applications, including ethanol production. The use of pentose sugars from hemicelluloses represents an opportunity to further increase production efficiencies. In the present study, we describe a global gene expression analysis of A. niger XlnR- and AraR-deficient mutant strains, grown on a d-xylose/. l-arabinose monosaccharide mixture and steam-exploded sugarcane bagasse. Different gene sets of CAZy enzymes and sugar transporters were shown to be individually or dually regulated by XlnR and AraR, with XlnR appearing to be the major regulator on complex polysaccharides. Our study contributes to understanding of the complex regulatory mechanisms responsible for plant polysaccharide-degrading gene expression, and opens new possibilities for the engineering of fungi able to produce more efficient enzymatic cocktails to be used in biofuel production.
Original language | English |
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Pages (from-to) | 29-45 |
Number of pages | 17 |
Journal | Fungal Genetics and Biology |
Volume | 60 |
DOIs | |
Publication status | Published - 1 Nov 2013 |
Funding
The authors would like to thank Robson Tramontina and Diogo Robl for technical assistance with the sugar analysis. W.R.S., P.F.G., N.A.B., and G.H.G. would like to thank Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq), Brazil, for financial support. E.B. was supported by a grant of the Dutch Foundation for Applied Science (STW), division of the Netherlands Organisation for Scientific research (NOW) UGC 07063 to R.P.d.V. G.P.M.A. was supported by a grant of the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil. Appendix A
Keywords
- AraR
- Aspergillus niger
- Biofuels
- Plant polysaccharide-degrading genes
- Sugarcane bagasse saccharification
- XlnR
ASJC Scopus subject areas
- Microbiology
- Genetics