Screening And Characterization Analysis Of A Phenol-degrading Bacteria Of Producing Biosurfactant

Phenol and phenolic compounds are environmental pollutants in industrial wastewater from coal conversion,refineries and petrochemical plants.Due to the toxicity of phenol,it is of great importance to environmental protection for the effective removal of these toxic compounds.Biotechnology is widely used to remove these toxic compounds because of its less harm,no secondary pollution and low cost.As an economical,effective and non-secondary pollution wastewater treatment technology,biological process is the first choice to treat phenol-containing wastewater.However,due to the hydrophobic,toxic,difficult degradation properties of phenol,the degradation performance of microorganism would be inhibited.Some studies had shown that the degradation performance of microorganisms can be improved by the addition of certain surfactants.The surfactant is a parent molecule containing a hydrophilic group and a hydrophobic group,which has solubilization and adsorption to hydrophobic organics,and can promote the degradation of hydrophobic organics by microbial.The aggregation of the biological surfactant in the solution can capture the free phenol that may lead to the decrease of free phenol in the solution,reduce the toxicity of the phenol to the thalli,and then enhance the degradation performance of phenol by.The exogeneous surfactant through the method of chemical synthesis is difficult to degrade,that can cause the secondary pollution to the environment.The biological surfactant has widely concerned due to the advantages of biodegradation,no secondary pollution,no toxicity or low toxicity and biodegradability.Therefore,it is a hot research issue to seek a class of high-efficiency phenol-degradation strains that can produce self-generated surfactant.The purpose of this paper is to isolate and screen the strain that can produce biological surfactants and have high efficiency in the degradation of phenol.In this paper,a highly efficient phenol degrading strain BPH-3,was isolated and screened from the activated sludge of Wuhan Petrochemical Sewage Treatment Plant,and the strain was identified and cultured conditions were optimized for high degradation efficiency of phenol and the yield of biosurfactant.The biosurfactant was identified as well as the investigation of the physical and chemical properties.The main conclusions were as follows:?1?After enrichment,acclimation,isolation and purification of a phenol-degrading bacterium producing biosurfactant,the strain was identified as Pseudomonas pseudomonas by physiological,biochemical,morphological and 16S rDNA identification.The strain was named Pseudomonas sp.BPH-3,By the Chinese typical culture preservation center,the preservation number is:CCTCC NO:M 2019144.?2?The optimum culture conditions for phenol degradation by strain Pseudomonas sp.BPH-3 were as follows:the rotating speed of pH=7,shaking speed was 150 r/min,the temperature was 30?,and the tolerance salinity was less than 4%.When the concentration of phenol was 600mg/L,the degradation rate could reach 100%within 12hours.The degradation kinetics of strain BPH-3 was in accordance with the Haldane model.The kinetic equation is:???The parameters of the kinetic equation were as follows:Maximum specific degradation rate v_m=0.7911 h^-1;substrate half-saturation and constant K_s=130.3279 mg/L;inhibition constant K_sl=1546.054mg/L.?3?The optimum culture conditions for biosurfactant production by strain Pseudomonas sp.BPH-3 were as follows:peanut oil as carbon source 20.0 g/L,sodium nitrate as nitrogen source 1.5g/L,the shaking speed 175r/min,temperature 35?,pH=7.Under the optimal culture conditions,the yield of the biosurfactant produced by Pseudomonas sp.BPH-3 was 567 mg/L.?4?The biosurfactants produced by strain Pseudomonas sp.BPH-3 were identified as glycolipid surfactants by infrared spectroscopy and thin layer chromatography.The critical micelle concentration?CMC?of the biosurfactant produced by strain BPH-3 was150 mg/L with excellent emulsification performance strong tolerance to temperature,pH and salinity.The addition of the biosurfactant into the medium could significantly promote the degradation of phenol by strain Pseudomonas sp.BPH-3.