Extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms: characterization by infrared spectroscopy and proteomics.
The composition of extracellular polymeric substances (EPS) from Shewanella sp. HRCR-1 biofilms was investigated using infrared spectroscopy and proteomics to provide insight into potential ecophysiological functions and redox activity of the EPS. Both bound and loosely associated EPS were extracted from Shewanella sp. HRCR-1 biofilms prepared using a hollow-fibre membrane biofilm reactor. Fourier transform infrared spectra revealed the presence of proteins, polysaccharides, nucleic acids, membrane lipids and fatty acids in the EPS fractions. Using a global proteomic approach, a total of 58 extracellular and outer membrane proteins were identified in the EPS. These included homologues of multiple Shewanella oneidensis MR-1 proteins that potentially contribute to key physiological biofilm processes, such as biofilm-promoting protein BpfA, surface-associated serine protease, nucleotidases (CpdB and UshA), an extracellular lipase, and oligopeptidases (PtrB and a M13 family oligopeptidase lipoprotein). In addition, 20 redox proteins were found in extracted EPS. Among the detected redox proteins were the homologues of two S. oneidensis MR-1 c-type cytochromes, MtrC and OmcA, which have been implicated in extracellular electron transfer. Given their detection in the EPS of Shewanella sp. HRCR-1 biofilms, c-type cytochromes may contribute to the possible redox activity of the biofilm matrix and play important roles in extracellular electron transfer reactions.
The Gene and Linda Voiland School of Chemical Engineering and Bioengineering and Center for Environmental, Sediment and Aquatic Research (CESAR), Washington State University, Pullman, WA, USA.
Bin
B
Cao
Liang
L
Shi
Roslyn N
RN
Brown
Yijia
Y
Xiong
Jim K
JK
Fredrickson
Margaret F
MF
Romine
Matthew J
MJ
Marshall
Mary S
MS
Lipton
Haluk
H
Beyenal
D001426:Bacterial Proteins / Q000032:analysis; D018441:Biofilms; D019149:Bioreactors; D002853:Chromatography, Liquid; D003574:Cytochrome c Group / Q000737:chemistry; D004579:Electron Transport; D005110:Extracellular Space / Q000737:chemistry*; D008565:Membrane Proteins / Q000032:analysis; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D040901:Proteomics; D020592:Shewanella / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D053719:Tandem Mass Spectrometry
D001426:Bacterial Proteins; D003574:Cytochrome c Group; D008565:Membrane Proteins; D011108:Polymers