Study on the Breeding and Characterization of High-Efficiency Oil-Degrading Bacteria by Mutagenesis

Abstract

In the present study, a high-efficiency petroleum hydrocarbon-degrading bacterium MX1 was screened from petrochemical wastewater sludge, and MX1 was identified using morphological, physiological, and biochemical experiments and combined with 16S rDNA. Results showed that the the MX1 strain belongs to Enterobacter sp. The degradation conditions were an incubation time of 18 days, temperature of 30 °C, pH of 7, and salinity of 2% (w/v), and the degradation proportion was 37.41% for 7 days. The combination of microwave and ultraviolet mutagenesis yielded the strain MXM3U2. The mutant strain had a petroleum hydrocarbon breakdown efficiency of 56.74% after 7 days of culture, and this value was 51.66% higher than the original strain. The number of strains and the rate of degradation of n-alkanes (C16, C24, C32, and C40) decreased steadily with the increase in carbon chains in the degradation test. GC/MS (Gas chromatography mass spectrometry) results showed that in the process of degrading crude oil, the hydrocarbons with carbon number C < 24 were degraded first, followed by hydrocarbons with carbon number C > 24. The strains had a good degradation effect on pristane, naphthalene, and phenanthrene. In this study, a high-efficiency petroleum hydrocarbon-degrading bacterium was screened via microwave-ultraviolet composite mutagenesis technology.

Kerosene Biodegradation by Highly Efficient Indigenous Bacteria Isolated From Hydrocarbon-Contaminated Sites

“…The cellular morphs (shapes) of all potential kerosene-degrading bacteria were identified using microscopic examination (Gram’s staining). In addition, the isolates were also characterized biochemically, including catalase, urease, starch, and casein hydrolysis, as described in Zhang et al 25 For the catalase test, 2 to 3 drops of hydrogen peroxide (3%, v/v) were added to the overnight grown culture in the test tubes and the formation of vigorous bubbles indicated positive activity. For casein hydrolysis, isolates were grown overnight in nutrient broth and inoculated onto skim milk agar (HiMEDIA), and incubated at 30°C for 48 hours.…”

The Utilisation of Antarctic Microalgae Isolated from Paradise Bay (Antarctic Peninsula) in the Bioremediation of Diesel

“…However, longer alkanes (e.g., C19) showed much lower proportions of degradation. Based on the study of Zhang et al [46], pristane (C19) is a hydrocarbon that is composed of a complex branched structure. Due to this, the degradation of pristane is difficult.…”

“…[47], but strain WCY_AQ5_3 does not have this ability. However, it is important to note that the diesel most commonly utilised in Antarctica, Special Antarctic Blend (SAB), pre- Based on the study of Zhang et al [46], pristane (C 19 ) is a hydrocarbon that is composed of a complex branched structure. Due to this, the degradation of pristane is difficult.…”