Many strains of Gram-negative bacteria, such as Pseudomonas, are able to utilize a
variety of unusual chemicals, including a wide range or aromatic hydrocarbons and their
derivatives for growth. Bacteria with the potential to degrade sodium benzoate were
isolated, identified and grown as biofilms on sodium benzoate in a laboratory-scale
fluidized bed biofilm bioreactor. Four Pseudomonas strains identified as P. aeruginosa
(BDS2) P. putida (BDS1 and GR1) and Burkholderia cepecia (GR3FAR) were used in a
laboratory-scale FBBR together with two Bacillus strains - Bacillus macroides (SBSY4)
and Bacillus simplex (MAR). Sodium benzoate biodegradation capacities of these species
were compared under batch and continuous operations. Biofilm and planktonic bacterial
growth dynamics were monitored by plate counts, and optical density measurements
(230nm) determined benzoate biodegradation. Overall, higher attached and planktonic
bacterial counts were determined under batch compared to continuous mode. In addition
to this, the ability of attached cells to use sodium benzoate as their sole carbon source
was compared to their suspended counterparts in a batch system. There were more
attached counts compared to suspended cells and attached cells apparently degraded
sodium benzoate better than planktonic cells. Similarly, higher rates of benzoate
depletion were found to occur under batch compared to the continuous system. It thus
appeared that more cell growth implied more substrate consumption. SEM showed
attached cells and microcolonies of all the isolates on GAC, indicating their biofilmforming
abilities.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/6616 |
| Date | 05 March 2009 |
| Creators | Ntoampe, Mannana Selina |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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