AUTHOR=Alves Joana I. , Alves M. Madalena , Plugge Caroline M. , Stams Alfons J. M. , Sousa Diana Z. 

TITLE=Comparative Analysis of Carbon Monoxide Tolerance among Thermoanaerobacter Species

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01330

DOI=10.3389/fmicb.2016.01330

ISSN=1664-302X

ABSTRACT=<p>An anaerobic thermophilic strain (strain PCO) was isolated from a syngas-converting enrichment culture. Syngas components cannot be used by strain PCO, but the new strain is very tolerant to carbon monoxide (pCO = 1.7 × 10<sup>5</sup> Pa, 100% CO). 16S rRNA gene analysis and DNA-DNA hybridization revealed that strain PCO is a strain of <italic>Thermoanaerobacter thermohydrosulfuricus</italic>. The physiology of strain PCO and other <italic>Thermoanaerobacter</italic> species was compared, focusing on their tolerance to carbon monoxide. <italic>T. thermohydrosulfuricus, T. brockii</italic> subsp. <italic>finnii, T. pseudethanolicus</italic>, and <italic>T. wiegelii</italic> were exposed to increased CO concentrations in the headspace, while growth, glucose consumption and product formation were monitored. Remarkably, glucose conversion rates by <italic>Thermoanaerobacter</italic> species were not affected by CO. All the tested strains fermented glucose to mainly lactate, ethanol, acetate, and hydrogen, but final product concentrations differed. In the presence of CO, ethanol production was generally less affected, but H<sub>2</sub> production decreased with increasing CO partial pressure. This study highlights the CO resistance of <italic>Thermoanaerobacter</italic> species.</p>