Abstract
The contact angle, which is generally used to evaluate the hydrophobicities of pure bacterial strains and solid surfaces, was used to study mixed cell cultures of bacteria involved in anaerobic digestion. Previously published data and data from this study showed that most acidogens are hydrophilic (contact angle, <45(deg)) but most of the acetogens and methanogens isolated from granular sludge are hydrophobic (contact angle, >45(deg)). The hydrophobicities of mixtures of hydrophilic and hydrophobic cells were found to be linearly correlated with the cell mixing ratio. The hydrophobicities of cells present in effluents from upflow anaerobic sludge bed reactors which were treating different types of substrates were different depending on the reactor conditions. When the reactor liquid had a high surface tension, cells sloughing off from sludge granules, as well as cells present on the outer surfaces of the granules, were hydrophobic. Short-term batch enrichment cultures revealed that proteins selected for highly hydrophilic cells. Long-term in-reactor enrichment cultures revealed that sugars selected for hydrophilic acidogens on the surfaces of the granules, while fatty acids tended to enrich for hydrophobic methanogens. When linear alkylbenzenesulfonate was added, the cells on the surfaces of granules became more hydrophilic. Control tests performed with pure cultures revealed that there was no change in the surface properties due to linear alkylbenzenesulfonate; hence, the changes in the wash-out observed probably reflect changes in the species composition of the microbial association. A surface layer with moderate hydrophobicity, a middle layer with extremely high hydrophobicity, and a core with high hydrophobicity could be distinguished in the grey granules which we studied.
Full Text
The Full Text of this article is available as a PDF (181.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Absolom D. R., Lamberti F. V., Policova Z., Zingg W., van Oss C. J., Neumann A. W. Surface thermodynamics of bacterial adhesion. Appl Environ Microbiol. 1983 Jul;46(1):90–97. doi: 10.1128/aem.46.1.90-97.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Busscher H. J., Weerkamp A. H., van der Mei H. C., van Pelt A. W., de Jong H. P., Arends J. Measurement of the surface free energy of bacterial cell surfaces and its relevance for adhesion. Appl Environ Microbiol. 1984 Nov;48(5):980–983. doi: 10.1128/aem.48.5.980-983.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gerson D. F. Cell surface energy, contact angles and phase partition. I. Lymphocytic cell lines in biphasic aqueous mixtures. Biochim Biophys Acta. 1980 Nov 4;602(2):269–280. doi: 10.1016/0005-2736(80)90310-7. [DOI] [PubMed] [Google Scholar]
- Grotenhuis J. T., Plugge C. M., Stams A. J., Zehnder A. J. Hydrophobicities and electrophoretic mobilities of anaerobic bacterial isolates from methanogenic granular sludge. Appl Environ Microbiol. 1992 Mar;58(3):1054–1056. doi: 10.1128/aem.58.3.1054-1056.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lens P. N., De Beer D., Cronenberg C. C., Houwen F. P., Ottengraf S. P., Verstraete W. H. Heterogeneous Distribution of Microbial Activity in Methanogenic Aggregates: pH and Glucose Microprofiles. Appl Environ Microbiol. 1993 Nov;59(11):3803–3815. doi: 10.1128/aem.59.11.3803-3815.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lindahl M., Faris A., Wadström T., Hjertén S. A new test based on 'salting out' to measure relative surface hydrophobicity of bacterial cells. Biochim Biophys Acta. 1981 Nov 5;677(3-4):471–476. doi: 10.1016/0304-4165(81)90261-0. [DOI] [PubMed] [Google Scholar]
- MacLeod F. A., Guiot S. R., Costerton J. W. Layered structure of bacterial aggregates produced in an upflow anaerobic sludge bed and filter reactor. Appl Environ Microbiol. 1990 Jun;56(6):1598–1607. doi: 10.1128/aem.56.6.1598-1607.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rijnaarts H. H., Norde W., Bouwer E. J., Lyklema J., Zehnder A. J. Bacterial Adhesion under Static and Dynamic Conditions. Appl Environ Microbiol. 1993 Oct;59(10):3255–3265. doi: 10.1128/aem.59.10.3255-3265.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Loosdrecht M. C., Lyklema J., Norde W., Schraa G., Zehnder A. J. The role of bacterial cell wall hydrophobicity in adhesion. Appl Environ Microbiol. 1987 Aug;53(8):1893–1897. doi: 10.1128/aem.53.8.1893-1897.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]