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Extracellular polymeric substances from Shewanella sp. HRCR‐1 biofilms: characterization by infrared spectroscopy and proteomics
Author(s) -
Cao Bin,
Shi Liang,
Brown Roslyn N.,
Xiong Yijia,
Fredrickson Jim K.,
Romine Margaret F.,
Marshall Matthew J.,
Lipton Mary S.,
Beyenal Haluk
Publication year - 2011
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2010.02407.x
Subject(s) - shewanella oneidensis , biofilm , extracellular polymeric substance , shewanella , biology , biochemistry , extracellular , redox , polysaccharide , bacterial outer membrane , biofouling , electron transfer , microbiology and biotechnology , bacteria , chemistry , membrane , escherichia coli , gene , genetics , organic chemistry
Summary 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.