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Structure and shear strength of microbial biofilms as determined with confocal laser scanning microscopy and fluid dynamic gauging using a novel rotating disc biofilm reactor
Author(s) -
Möhle Roland B.,
Langemann Timo,
Haesner Marian,
Augustin Wolfgang,
Scholl Stephan,
Neu Thomas R.,
Hempel Dietmar C.,
Horn Harald
Publication year - 2007
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21448
Subject(s) - biofilm , sloughing , shear (geology) , shear force , confocal laser scanning microscopy , substrate (aquarium) , chemistry , materials science , shear strength (soil) , composite material , bacteria , microbiology and biotechnology , biology , geology , soil science , medicine , ecology , genetics , pathology , soil water
The cohesive strength of microbial biofilms cultivated on a rotating disc has been measured using fluid dynamic gauging (FDG). The thickness of heterotrophic mixed culture biofilms was found to depend on substrate concentration and shear force at the biofilm surface during the cultivation. For high substrate concentrations and low shear forces the biofilm thickness increased to several 100 µm within 7 days. Low substrate concentration and higher shear forces yielded thin biofilms of about 100 µm thickness. Independent from cultivation conditions and thickness of the biofilms their cohesive strength ranged between 6.0 and 7.7 N m −2 . The ratio between cohesive strength measured with FDG and shear forces applied during biofilm cultivation have ranged from 200 to 1,100. Higher concentrations of iron in the cultivation media has a positive effect on the stability of the biofilms cultivated. By using the CLSM technique a stable base biofilm with a high amount of stained EPS glycoconjugates could be visualized after gauging. The thickness of the base biofilm was about 100 µm for all biofilms cultivated and was not removable under the applied shear conditions used during FDG. Biotechnol. Bioeng. 2007;98: 747–755. © 2007 Wiley Periodicals, Inc.