Assembly Of Pseudomonas Aeruginosa Outer Membrane Protein P Incorporated Biomimetic Membranes And Its Application In Water Treatment

Eutrophication caused by excess phosphate in water is a major problem in water treatment.Although many methods have been proposed,they are often accompanied by problems such as non-recyclable raw materials,easy formation of secondary pollution,and low processing efficiency.These problems are solved as the membrane separation technique is applied to phosphate wastewater treatment.In recent years,protein-containing biomimetic membranes have been highly sought after for their specific selectivity and high efficiency.This also provides us with a new direction in the removal of phosphate from water.In order to selectively adsorb and remove phosphate in water,a biomimetic membrane containing P.aeruginosa outer membrane protein p was constructed on a hydrophilic polysulfone membrane and its effect on water treatment was verified.1.We chose to optimize the culture conditions of the cells from three aspects: temperature,pH and phosphate concentration.After research,it was found that the best growth and reproduction can be carried out under the conditions of 35 ° C,pH 7.5 and phosphate concentration of 0.2 mM.The maximum OD value of the cells can reach to 2.7.Phosphate concentration has a great influence on the expression of OprP.Therefore,we extracted and purified the protein from the bacterium which cultured under different phosphate concentrations and found that there were obvious protein strips only at the phosphate concentration of 0.1 mM.The band indicates that a large amount of the target protein exists in the cell at a phosphate concentration of 0.1 mM.Since the optimum phosphate concentration for expression of the target protein was 0.1 mM so we chose 35 ° C,pH 7.5,and phosphate concentration of 0.1 mM phosphate as the final cell culture conditions.2.This chapter explores the effect of liposome particle size uniformity on protein insertion.We first selected different phospholipid concentrations,drying methods and ultrasonic time to verify their effect on the uniformity of liposome particle size.The particle size of the liposome was determined by dynamic light scattering.It was found that the different phospholipid concentration and drying methods had little effect on the uniformity of the liposome particle size,and the hydration ultrasonic time which too long or too short has big effect on the size of liposome.The prepared liposomes were observed by transmission electron microscopy and found the difference in the particle size of the liposomes,which is consistent with the particle size results detected by dynamic light scattering.We chose to detect the amount of protein insertion in liposomes which produced under different ultrasound time conditions.The protein insertion was the least when the ultrasonic time was 1 min,and the protein insertion was the most when the ultrasonic time was 5 min.This is the same as the uniformity of liposome particle size.This indicates that the number of protein insert is related to the particle size of the liposome.3.We chose the hydrophilic polysulfone membrane as support substrates for OprP incorporated biomimetic membranes biofilms.Different dosage of polyethylene glycol was used as the polymeric additives in the casting solution methods to change the hydrophilicity of membranes.By comparing the porosity,contact angle,water flux and protein rejection of the prepared polysulfone membranes,we found that the polysulfone membrane containing 6% polyethylene glycol exhibited the best performance.The surface morphology of the polysulfone membrane containing 6% polyethylene glycol was observed by scanning electron microscopy.The surface pore size of the membrane was about 200 nm and the pores were uniform.4.The properties of the assembled OprP incorporated biomimetic membranes were investigated.And its specific adsorption and removal effects on phosphate were verified mainly from adsorption,dialysis and electrodialysis.In terms of membrane adsorption,the concentration of phosphate in the experimental apparatus containing the OprP incorporated biomimetic membranes decreased from 6.3 mg/L to 5.53 mg/L in the five hours.In the case of membrane dialysis,the phosphate concentration in anode chamber within increased by about 0.1mg / L,indicating that the mass transfer efficiency is very low.In order to improve mass transfer efficiency,we chose electrodialysis.In which the penetration rate of phosphate under energized conditions is 3 times that of non-voltage conditions.The biomimetic membrane was able to specifically select phosphates under conditions of mixed anions.In this paper,a kind of OprP incorporated biomimetic membranes was constructed after preparation of the three major components of the biomimetic membrane and proved it has the capable of adsorbing and removing phosphate in water.The construction of biomimetic membrane is a multidisciplinary technology.This study not only provides new ideas and methods for solving the problem of phosphate pollution water but also contribute to development and application of the biomimetic membrane technology.