Hypoxia is regulating enzymatic wood decomposition and intracellular carbohydrate metabolism in filamentous white rot fungus

Hans Mattila, Mari Mäkinen, Taina Lundell

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Background

Fungal decomposition of wood is considered as a strictly aerobic process. However, recent findings on wood-decaying fungi to produce ethanol from various lignocelluloses under oxygen-depleted conditions lead us to question this. We designed gene expression study of the white rot fungus Phlebia radiata (isolate FBCC0043) by adopting comparative transcriptomics and functional genomics on solid lignocellulose substrates under varying cultivation atmospheric conditions.

Results

Switch to fermentative conditions was a major regulator for intracellular metabolism and extracellular enzymatic degradation of wood polysaccharides. Changes in the expression profiles of CAZy (carbohydrate-active enzyme) encoding genes upon oxygen depletion, lead into an alternative wood decomposition strategy. Surprisingly, we noticed higher cellulolytic activity under fermentative conditions in comparison to aerobic cultivation. In addition, our results manifest how oxygen depletion affects over 200 genes of fungal primary metabolism including several transcription factors. We present new functions for acetate generating phosphoketolase pathway and its potential regulator, Adr1 transcription factor, in carbon catabolism under oxygen depletion.

Conclusions

Physiologically resilient wood-decomposing Basidiomycota species P. radiata is capable of thriving under respirative and fermentative conditions utilizing only untreated lignocellulose as carbon source. Hypoxia-response mechanism in the fungus is, however, divergent from the regulation described for Ascomycota fermenting yeasts or animal-pathogenic species of Basidiomycota.

Original languageEnglish
Article number26
JournalBiotechnology for Biofuels
Volume13
Issue number1
Number of pages17
ISSN1754-6834
DOIs
Publication statusPublished - 24 Feb 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1183 Plant biology, microbiology, virology
  • Wood decay fungi
  • Lignocellulose biodegradation
  • White rot fungi
  • Basidiomycota
  • Gene expression data
  • Transcriptome analysis
  • Genomics
  • Enzyme activity
  • Carbohydrate active enzymes
  • Bioethanol
  • Fermentation
  • Oxygen depletion
  • Hypoxia
  • Metabolic pathways
  • Regulation
  • Phlebia radiata
  • Fungal metabolism
  • Gene expression
  • BIOCONVERSION

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