Characterization of methanol degrading bacteria and their roles in promoting plant growth
Lim, Jia Rong
Date of Issue2017-05-11
School of Civil and Environmental Engineering
Algal blooms occur when there is a large increase in concentrations of algae. Such high concentrations of algae in the environment may be detrimental to other organisms. Interactions between algae and bacteria may be a factor which promotes algal growth. It was found that the availability of nutrients provided to the algae such as phosphorus and nitrogen plays an important role in affecting the algal growth and some bacteria were reported to have the ability to solubilize phosphate and fix nitrogen. This study analyzed the nitrogen fixing and phosphate solubilizing abilities of methanol degrading bacteria, Methylobacterium leisingeri, Methylophilus rhizosphaerae, Methylobacterium radiotolerans and Methylophilus sp. isolated from reservoir water. Experiments were conducted to screen for nitrogen fixation and inorganic phosphate solubilization properties. Kinetics of phosphate release was quantified by measuring free phosphate released, pH changes and bacterial growth. Lastly, the effect of bacterial supernatants on the growth of the alga Chlamydomonas reinhardtii was investigated. Based on the results obtained from the experiments, it was found that these four methanol degrading bacteria were not able to perform nitrogen fixation. However, M. leisingeri, M. rhizosphaerae and Methylophilus sp. were able to solubilize phosphate in the Pikovskaya medium and phosphate solubilization abilities were growth dependent. At both photoheterotrophic and photoautotrophic culture conditions, there was no significant increase in growth when C. reinhardtii was supplemented with bacterial supernatants as compared to when the algal culture was supplemented with uninoculated Pikovskaya Medium.
Final Year Project (FYP)
Nanyang Technological University