Biodegradation of waste and pure canola oil by cold-adapted Rhodococcus sp. AQ5-07 from Antarctica

• Main Author: Ibrahim, Salihu
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: Waste product - Biodegradation; Biodegradation; Canola oil; Antarctic; Antarc*; Antarctica
• Online Access: http://psasir.upm.edu.my/id/eprint/91951/; http://psasir.upm.edu.my/id/eprint/91951/1/FBSB%202020%2015%20UPMIR.pdf

With the increase in human activities in Antarctic region, the possibility of vegetable oil spillage becomes unavoidably high. The removal of oils including canola oil from the environment and wastewater using biological approaches is needed since the thermal process of oil degradation is ineffective and requires the use of high temperatures. More so, thermal degradation leads to the generation free radicals. Thus, in this present study, the potential canola oil-degrading ability of cold-adapted Rhodococcus sp. AQ5-07 from Antarctica was evaluated using one-factor-at-a-time (OFAT), and response surface method (RSM). The bacterial growth kinetics was examined and screened for biosurfactant production. The ability of Rhodococcus sp. AQ5-07 to degrade canola oil in the presence of different heavy metals and xenobiotics was also tested. Furthermore, canola oil degradation pathway was investigated via whole genome analysis. Rhodococcus sp. strain AQ5-07 was found to have a high canola oil-degrading ability over other strains tested. Considerable degradation (78.60% and 70.14%) of 3% waste and pure canola oil was achieved by this bacterium when incubated with 1.0 g/L ammonium sulphate, 0.3 g/L yeast extract, pH 7.5 and 10% inoculum at 10°C over 72 h incubation period. Optimisation of the medium conditions using response surface methodology (RSM) resulted in an increase in both oil degradations (87.61% and 86.34%). Three out of the 10 heavy metals tested namely mercury (Hg), cadmium (Cd) and silver (Ag) had a significant effect on canola oil degradation at 1 ppm. The IC50 values of the waste canola oil (WCO) for Hg, Cd and Ag were found to be 0.3866, 0.4539 and 0.3217 ppm, respectively. Meanwhile, for the pure canola oil (PCO), the IC50 was found to be Hg (0.2495), Cd (0.5452) and Ag (0.3088), respectively. This shows that the strain can also withstand 10 mg/L acrylamide, 50 mg/L phenol and 0.5% (v/v) diesel, respectively, for both oils. The bacterium was also found to produce high biosurfactant with beta haemolysis, ...