Analysis of metabolic tendency and interactions of 12 bacterial strains used in air purification applications

• Main Author: Mohamad Faizal Mohamad Jasni
• Other Authors: Sze Chun Chau
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Biological sciences::Microbiology::Microorganisms
• Online Access: http://hdl.handle.net/10356/59586
• Institution: Nanyang Technological University

Bio-augmentation is a waste management technique that involves addition of foreign micro-organism(s) into contaminated sites to utilise the micro-organisms’ metabolic capacity to hasten the degradation or removal of the pollutants present. Before this current investigation, strain selection for prior bio-augmentation studies has already been performed, giving rise to 114 bacterial strains from 11 genera. Representative strains from these 11 genera were studied for their hydrocarbon degradation potential in air-purification applications. The approach to that strain selection followed an unconventional strategy that relied on stable relationships already in place within the microbial community. This project further investigated 12 selected strains from the 11 genera on their hydrocarbon degradation potential as single isolates and as co-cultures. Single isolates experiments using 2,6-dichlorophenol indophenol (DCPIP) as reduction indicator and hexane as sole carbon source revealed 3 out of 11 strains to be hexane-reducing/degrading strains. The other 8 strains did not appear to reduce hexane. Co-culture experiments suggested some level of bacterial interplay occurring within the strains. Results however were contradicting between different co-culture experiments. Solid agar co-culture lawn experiments showed inhibition of growth of NES 140 (a hexane-degrading strain) in the presence of NES 28 (a non-hexane degrading strain) whereas liquid co-culture experiments of NES 140 with the supernatant of NES 28 showed somewhat enhanced growth of NES 140. This project also attempts to identify other hydrocarbons, namely formaldehyde and methanol, that can be reduced by the strains. Initial findings suggested that NES 28, a non-hexane-degrading strain, may be able to utilise formaldehyde. Lastly, this project also attempts to not only characterise the strains metabolically, but also bio-molecularly, via end-point polymerase chain reaction (PCR) experiments using specific primers (previously designed) and an experimental annealing temperature of 63°C during PCR.