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Screening, Identification and Low-Temperature Degradation Characteristics Study of Cold-Adapted Petroleum Hydrocarbon-Degrading Bacteria Isolated from Antarctic Sea

Author: LiuFangMing
Tutor: ZuoJinLai
School: First Institute of Oceanography of State Oceanic Administration
Course: Marine biology
Keywords: Antarctic Marine The Antarctic low temperature degrading bacteria Diesel fuel 16S rRNA Molecular Identification Low - temperature degradation characteristics Low Temperature Bioremediation technology
CLC: X172
Type: Master's thesis
Year: 2008
Downloads: 358
Quote: 2
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Abstract

Antarctic has a unique geographical and climate characteristics, its main feature is a great change light radiation, the seasonal illumination time. Antarctic marine systems perennial low temperature (usually -1.8 ° C to 2.0 ° C), high salt (sea water salinity is generally 34 ‰ ~ 35 ‰, the salinity of the salt in the sea ice capsule and salt channel up to 150 ‰) in such a low temperature, strong radiation and high salinity of the natural environment, marine microorganisms must have unique physiological and biochemical and molecular mechanisms, therefore, not only to the Antarctic microorganisms is an excellent material for biocompatibility studies at low temperatures, but also the low temperature bioactive substances (low temperature enzyme, PUFA) the best sources and other low-temperature bio-engineered bacteria. With the increasingly frequent offshore oilfield, mining and marine transportation, marine petroleum hydrocarbon pollution is more and more serious, that is considered to be mankind's last piece of pure land of Antarctica was not spared. In recent years, the Antarctic expedition, prospecting, and the rise of tourism, especially large tanker sank, resulting in a large number of petroleum hydrocarbon leak, a serious threat to the security of the Antarctic ecosystem, has attracted world wide attention, in the Antarctic in a very vulnerable ecosystem, any small ecological environment pollution will cause serious damage to ecosystems. Bioremediation is an important way to eliminate the marine petroleum hydrocarbon pollution, low temperature low temperature degradation of petroleum hydrocarbons in this article from the the Antarctic seawater sea ice samples screened bacteria, in order to lay the foundation for Cryobiology of marine petroleum hydrocarbon pollution remediation technology applications. In this paper, MMC inorganic liquid culture and MMC agar plate culture method of combining screening samples from Antarctic seawater sea ice bacteria capable of efficient low-temperature degradation of petroleum hydrocarbons in bacteria, tablet growth and degradation rate of the screening to four Antarctic cryogenic degrading bacteria test; molecular identification method using 16S rRNA phylogenetic tree was constructed of four the Antarctic low temperature degradation bacteria were identified; single-factor test to determine the the Antarctic low temperature degradation bacteria NJ49 optimal nutrition and growth conditions through biological shaker; through naphthalene cryogenic degradation, diesel low temperature degradation GC-MS spectrum dehydrogenase test, produce biosurfactant test, fatty acid changes in the test, and to study the bacteria the NJ49 the degradation characteristics of Antarctic low temperature degradation and low temperature flexibility. Mainly to obtain the following results: 1. Screening from Antarctic seawater sea ice samples to four the Antarctic low temperature degrading bacteria, namely NJ41, NJ44, NJ49, NJ289. Flat visible the count tests showed that the culture 20d after NJ41, NJ44, NJ49 and NJ289 are growing well, the Antarctic low temperature degradation the bacteria the NJ49 broth cells can close 106.8CFU/ml. On four Antarctic cryogenic degrading bacteria to 15 ℃ degradation tests showed that degradation ability of different strains of diesel, which the Antarctic low temperature degrading bacteria of NJ49 degradation rate was the highest, up to 68%. 2 shows that the observed results of the morphological characteristics of the degrading bacteria 4 Antarctic Low Antarctic Low degrading bacteria NJ41 is a sphere, its diameter is 1.0 to 1.2 μm, the remaining three degrading bacteria as RODS, length in the range between 0.7 ~ 2.8μm . 4 the Antarctic low temperature degradation bacteria do not form spores have flagella can move. 16S rRNA molecule identification results showed: Antarctic low temperature degradation bacteria NJ41 the Antarctic low temperature degradation bacteria belonging to the dynamic coccus (Planococcus); NJ49 belongs the Shewanella (Shewanella); Antarctic low temperature degradation bacteria NJ289 false Alteromonas genus (Pseudoalteromonas) ; Antarctic low temperature degradation bacteria NJ44 needs to be further identified. The research results show that the highest degradation rate of Antarctic cryogenic degrading bacteria NJ49 growth under various environmental conditions, and the degradation of diesel capacity that the optimal conditions for the growth and degradation: the initial pH of 7.5 and a temperature of 15 ° C. 6%, salinity, broth quantity of 80ml best nitrogen source was ammonium nitrate, the best source of phosphorus for the mixture of potassium dihydrogen phosphate and dipotassium hydrogen. The surfactant is added to promote the Antarctic Low degradation bacteria a NJ49 growth and degradation, especially anionic surfactant (SDS) and non-ionic surface active agent (rhamnolipid) combined to improve the degradation rate of the strain. Antarctic cryogenic degrading bacteria NJ49 low temperature degradation characteristics of the study results showed that the 15 ° C conditions, it can grow in mineral medium naphthalene as the sole carbon and energy, and naphthalene degradation. Antarctic cryogenic degrading bacteria NJ49 of diesel degradation was determined by GC-MS, the pattern shows that the control containing l8 alkanes between C9 ~ C26 diesel by the Antarctic low temperature degradation bacteria NJ49 low temperature degradation process of residual oil fractions, only the detected C15 ~ C217 alkanes, not only the types of alkanes is significantly reduced, and also reduce the number of single-alkane content. By the Antarctic low temperature degradation bacteria the NJ49 production dehydrogenase test that enzyme activity is lower than 15 ℃, 5 ℃ dehydrogenase enzyme activity, indicating that the low-temperature limit of the Antarctic cryogenic degrading bacteria NJ49 enzyme activity; supplies diesel MMC medium dehydrogenase enzyme activity, higher than 2216E medium inferred determination of dehydrogenase is an enzyme degradation diesel. Antarctic Low degrading bacteria NJ49 production surfactant test results for 5 ℃ and 20 ° C under the conditions, the strain produces no surfactant. Fatty acid composition according to the measurement data, it is found Antarctic Low degrading bacteria NJ49 degradation of the low temperature (5 ℃), the fatty acid component is changed, and the kind of unsaturated fatty acids and fatty acid content have a single species. 5 ℃ under the conditions of low temperature Antarctic degrading bacteria NJ49 can produce a variety of unsaturated fatty acids, and its content is higher than the temperature (20 ° C) conditions. Low temperature, cryogenic Antarctic degrading bacteria NJ49 fat saturation decreases from 1.22 down to 0.77, and infer the low temperature degradation bacteria through fatty acid changes to adapt to the low temperature degradation. To low temperature degradation of petroleum hydrocarbons in marine bacteria isolated from Antarctic seawater sea ice is the first of its kind in the country, that these Antarctic cryogenic degrading bacteria cryogenic marine oil pollution bioremediation provides bacteria sources. Hydrocarbon low temperature of the the Antarctic low temperature oil degrading bacteria degradation characteristics, will be the cleanup of petroleum hydrocarbon contaminants in low-temperature waters, provide effective bioremediation technology methods.

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