Environmental Engineering Reference
In-Depth Information
Table 6.3 Bioilm characterisation methods
Prope
rties/analysis
Methods
Surface
analysis
Structure
Light microscopy, epiluorescence, SEM, CLSM,
AFM and PAS
Identiication of
microbes (dead/live)
Light microscopy, epiluorescence, SEM,
luorescence
in situ
hybridisation, 16S rRNA and PCR
Surface
hydrophobicity
Contact angle measurement
Total bioilm
amount
Biomass
Dry weight
Bioilm thickness
Microscopy, image analysis and electrical
conductance/capacitance
Bioilm
components
EPS FTIR spectroscopy, ATR-IR, total carbohydrate
content and XPS
Proteins Protein estimation, FTIR spectroscopy and XPS
Lipopolysaccharides Limulus amebocyte lysate test and GC-MS analysis
Activity
estimation
ATP
ATP assay
Immunoassay
Oligonucleotide probes
ATP: Adenosine triphosphate
EPS:
Exopolysaccharide
PCR: Polymerase chain reaction
RNA: Ribosomal ribonucleic acid
An optical relectance assay could be a very useful tool in future as it would give rapid
quantitative assessment of phenotypic variation among isolates. It could measure
bioilm formation on both opaque and non-opaque surfaces [40] .
FTIR spectroscopy is a non-destructive technique that has been widely used to monitor
and analyse EPS formation in bioilms [41]. The advantage of this technique is that
the bioilms can be monitored directly, online and in real time. The region between
4,000 and 500 cm
-1
shows characteristic bands for functional groups of peptides,
proteins, polysaccharides, phospholipids and nucleic acids [42]. The limitation of
this technique is that it allows the analysis of only the base layer of the substrate of
approximately 1 μm. It is also hard to distinguish between dead and live cells from
a single spectra [6] .
NMR spectroscopy can help to study substrate consumption and production of
intracellular metabolites in dense suspensions of bacteria. In this technique radio
