Profile of Secreted Hydrolases, Associated Proteins, and SlpA in Thermoanaerobacterium saccharolyticum during the Degradation of Hemicellulose

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Applied and Environmental Microbiology

DOI:https://doi.org/10.1128/AEM.00998-14· OSTI ID:1149418

Currie, Devin ^[1]; Guss, Adam M ^[2]; Herring, Christopher ^[3]; Johnson, Courtney M ^[2]; Lankford, Patricia K ^[2]; Brown, Steven D ^[2]; Lynd, Lee R ^[4]

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1. Dartmouth College
2. ORNL
3. Mascoma Corporation
4. Thayer School of Engineering at Dartmouth

Thermoanaerobacterium saccharolyticum, a Gram-positive thermophilic anaerobic bacterium, grows robustly on insoluble hemicellulose, which requires a specialized suite of secreted and transmembrane proteins. We report here the characterization of proteins secreted by this organism. Cultures were grown on hemicellulose, glucose, xylose, starch, and xylan in pH-controlled bioreactors, and samples were analyzed via spotted microarrays and liquid chromatography-mass spectrometry. Key hydrolases and transporters employed by T. saccharolyticum for growth on hemicellulose were, for the most part, hitherto uncharacterized and existed in two clusters (Tsac_1445 through Tsac_1464 for xylan/xylose and Tsac_1344 through Tsac_1349 for starch). A phosphotransferase system subunit, Tsac_0032, also appeared to be exclusive to growth on glucose. Previously identified hydrolases that showed strong conditional expression changes included XynA (Tsac_1459), XynC (Tsac_0897), and a pullulanase, Apu (Tsac_1342). An omnipresent transcript and protein making up a large percentage of the overall secretome, Tsac_0361, was tentatively identified as the primary S-layer component in T. saccharolyticum, and deletion of the Tsac_0361 gene resulted in gross morphological changes to the cells. The view of hemicellulose degradation revealed here will be enabling for metabolic engineering efforts in biofuel-producing organisms that degrade cellulose well but lack the ability to catabolize C5 sugars

• Research Organization: Oak Ridge National Laboratory (ORNL); BioEnergy Science Center (BESC)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1149418
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 16 Vol. 80; ISSN 0099-2240
• Country of Publication: United States
• Language: English