BioChem - DOS

Biofilm microenvironment induces a widespread adaptive amino-acid fermentation pathway conferring strong fitness advantage in Escherichia coli

PLoS genetics

Lé toffé , Sylvie; Chalabaev, Sabina; Dugay, José Stressmann, Franziska; Audrain, Bianca; Portais, Jean-Charles; Letisse, Fabien; Ghigo, Jean-Marc; Hughes, Diarmaid

<▼1><P>Bacterial metabolism has been studied primarily in liquid cultures, and exploration of other natural growth conditions may reveal new aspects of bacterial biology. Here, we investigate metabolic changes occurring when <I>Escherichia coli</I> grows as surface-attached biofilms, a common but still poorly characterized bacterial lifestyle. We show that <I>E</I>. <I>coli</I> adapts to hypoxic conditions prevailing within biofilms by reducing the amino acid threonine into 1-propanol, an important industrial commodity not known to be naturally produced by <I>Enterobacteriaceae</I>. We demonstrate that threonine degradation corresponds to a fermentation process maintaining cellular redox balance, which confers a strong fitness advantage during anaerobic and biofilm growth but not in aerobic conditions. Whereas our study identifies a fermentation pathway known in <I>Clostridia</I> but previously undocumented in <I>Enterobacteriaceae</I>, it also provides novel insight into how growth in anaerobic biofilm microenvironments can trigger adaptive metabolic pathways edging out competition with in mixed bacterial communities.</P></▼1><▼2><P><B>Author summary</B></P><P>Whereas <I>Escherichia coli</I> does not naturally produce the 1-propanol unless subjected to extensive genetic modifications, we show that this important industrial commodity is produced in hypoxic conditions inside biofilms. 1-propanol production corresponds to a native threonine fermentation pathway previously undocumented in <I>E</I>. <I>coli</I> and other <I>Enterobacteriaceae</I>. This widespread adaptive response contributes to maintain cellular redox balance and bacterial fitness in biofilms and other amino acid-rich hypoxic environments. This study therefore shows that mining complex lifestyles such as biofilm microenvironments provides new insight into the extent of bacterial metabolic potential and adaptive bacterial physiological responses.</P></▼2>

2017

Public Library of Science

cc-by

1553-7390

1553-7404

13

5

pp.e1006800

10.1371/journal.pgen.1006800

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART86354141

https://journals.plos.org/plosgenetics/article/file?id=10.1371/journal.pgen.1006800&type=printable