Article

Cellulose degradation and assimilation by the unicellular phototrophic eukaryote Chlamydomonas reinhardtii

  • Nature Communications 3, Article number: 1214 (2012)
  • doi:10.1038/ncomms2210
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Abstract

Plants convert sunlight to biomass, which is primarily composed of lignocellulose, the most abundant natural biopolymer and a potential feedstock for fuel and chemical production. Cellulose assimilation has so far only been described for heterotrophic organisms that rely on photosynthetically active primary producers of organic compounds. Among phototrophs, the unicellular green microalga Chlamydomonas reinhardtii is widely known as one of the best established model organisms. It occupies many habitats, including aquatic and soil ecosystems. This ubiquity underscores the versatile metabolic properties of this microorganism. Here we present yet another paradigm of adaptation for C. reinhardtii, highlighting its photoheterotrophic ability to utilize cellulose for growth in the absence of other carbon sources. When grown under CO2-limiting conditions in the light, secretion of endo-β-1,4-glucanases by the cell causes digestion of exogenous cellulose, followed by cellobiose uptake and assimilation. Phototrophic microbes like C. reinhardtii may thus serve as biocatalysts for cellulosic biofuel production.

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Acknowledgements

We thank the Centre for Biotechnology (CeBiTec) at Bielefeld University for access to the Technology Platforms.

Author information

Affiliations

  1. Department of Biology, Algae Biotechnology and Bioenergy–Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany.

    • Olga Blifernez-Klassen
    • , Viktor Klassen
    • , Anja Doebbe
    • , Klaudia Kersting
    • , Philipp Grimm
    • , Lutz Wobbe
    •  & Olaf Kruse

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Contributions

O.B.-K., A.D., V.K., L.W. and O.K. designed experiments. O.B.-K., K.K. and P.G. purified and identified CMCases in the secretome. O.B.-K. and V.K. conducted growth experiments and in vitro hydrolysis assays. A.D. carried out metabolomic analyses and radiolabelled CB uptake studies. O.B.-K. performed quantitative RT–PCR analyses and in silico studies. O.K. and L.W. wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Olaf Kruse.

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    Supplementary Information

    Supplementary Figure S1, Supplementary Tables S1-S4 and Supplementary References

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