Petroleum Hydrocarbon-Degrading Properties And Algicidal Activity Of A Rhodococcus Sp.

With the fast development of economic,water pollution become more and more seriously,of which petroleum pollution and harmful algae blooms has become a wideworld problem.Both of petroleum pollution and harmful algae blooms hindered mass exchange between the atmosphere and water,seriously affecting the water ecological environment.In addition,aromatic hydrocarbons and microcystins secreted by harmful algae,would endanger human health because of the enrichment through the food chain.Due to the advantages such as less investment,low running cost,and no secondary pollution,microbiological method for water pollutant treatment has become a hot spot in recent years.In this paper,a dibenzofuran-degrading bacterium Rhodococcus sp.strain p52 was used to study the degradation of petroleum hydrocarbons by gas chromatography,when alphatic hydrocarbons(n-tetradecane,n-hexadecane)and aromatichydrocarbons(phenanthrene,anthracene)co-existed.And degradatiln of 0#diesel fuel was analyzed by infrared spectrophotometry.At the same time,monooxygenase AlkB1,AlkB2 and Cytochrome P450,were cloned and expressed by polymerase chain reaction and SDS-PAGE electrophoresis.In addition,the algicidal range of Rhodococcus sp.strain p52 was also investigated and extracellular algicidal substances were analyzed by high performance liquid chromatography-mass spectrometry.The results showed that the presence of aliphatic hydrocarbons(tetradecane and hexadecane)promoted the degradation of aromatic hydrocarbons(phenanthrene and anthracene)by Rhodococcus sp.strain p52,while the presence of aromatic hydrocarbons(phenanthrene and anthracene)significantly inhibited the degradation of aliphatic hydrocarbons(tetradecane and hexadecane).Compared with tetradecane,hexadecane could promoted the degradation of phenanthrene more,and with the increase of the concentration of hexadecane,the degradation rate of phenanthrene increased.When initial concentration of diesel oil was about 4.4 g/L,the degradation rate of diesel oil reached 63.7%in 96 hours.In addition,related monooxygenases genes,alkBl,alkB2 and cypl85,were successfully cloned,in which cytochrome P450 monooxygenase expressed a lot when induced by IPTG Rhodococcus sp.strain p52 has a wide algicidal range,which including Microcystis aeruginosa,Microcystis flos-aquae,Anabaena cylindrica,Anabaena flos-aquae and Nodularia Spumigena.Rhodococcus sp.strain p52 attacked the harmful algae through an indirect mode,the extracellular algicidal substances included trans-3-indole acrylic acid,DL-piperidine acid and L-pyroglutamic acid.Rhodococcus sp.strain p52 not only has outstanding performance in degrading petroleum hydrocarbons,but also has great potential in algicidal application,which showed strain p52 has potential in water pollution treatment.