Study On Characters And Application Of Rhamnolipid Produced By Pseudomonase Aeruginosa NY3

Biosurfactants, with the notable advantages of its excellent surface activities,non-toxicity and biodegradability,these features suggest that the potential of thebiosurfactants in the environmental remediation project, the cosmetics industry,Petroleum industry, etc. so received more attention. However, because of its lowproduction and high cost, the application of it was limited. Based on a liberatorypreserved pseudomonase aeruginosa NY3, which showed it is a well rhamnolipidproducing bactrium, this paper aims to improve the production of rhamnolipid throughoptimization of medium condition and fermentation condition, and use this rhamnolipidin biodegradation of the oil-conta minated soil.Firstly, the best carbon source and nitrogen source were determined by therhamnolipid production of pseudomonas aeruginosa NY3, and optimized the conditionsof fermenting rhamnolipid. By FT-IR and other analysis methods, this paper studied theeffects of carbon and nitrogen source on physical-chemical characters and structure ofrhamnolipid produced by NY3, and then applied rhamnolipid in bioremediation oil-contaminated soil, The main research works and results were summarized as follows:（1） The optimal cultivation conditions for rhamnolipid production by the strainNY3was rapeseed oil6%（v/v）, ammonium nitrate2g/L, phosphate1.75g/L, initialpH=8,3%inoculation amount, at30℃and170r/min,under such conditions, theproduction of rhamnolipid was as high as14.36g/L with in73h, rhamnolipid productionimproved47.28%than before. Under this condition, the rhamnolipids were mixed withmonorhamnolipid and dirrhamnolipid, which contained about30%dirrhamnolipid, thecritical micelle concentration （CMC） of the rhamnolipid is200mg/L, the surfacetension is26.03mN/m. under CMC condition, the rhamnolipid shows excellent surface activity at high temperature（121℃）, high salinity（<2.8NcCl,or<1%（Al）2（SO4）3）and pH（3-12） and it also displays good stability.（2）The carbon source and nitrogen source influenced on the performance ofrhamnolipids produced by NY3. Compared with water-soluble carbon sources, whencarbon source was liposoluble substance like rapeseed oil, the performance of broth hada good emulsibility and an excellent performance to dispose oil from water, therhamnolipid has lower sugar contant. When ammonium nitrate and sodium nitrate withNO₃^-as nitrogen source, the rhamnolipid has higher suger contant. When mediumcontaining the NH₄⁺,it was more easier to contain unsaturated bond. When nitrogensource is ammonium nitrate, ammonium chloride, ammonium bicarbonate and peptone,the unsaturated bond content of rhamnolipids were14.02,10.93,10.98,13.64mmol/g.（3） Rhamnolipid produced by NY3can accelerate microbial bioremendiationoil-contaminated soil, In30days, increase the degradation rate about10%-18%.（4） Rhamnolipid produced by NY3can elute crude oil from sand, rhamnolipidconcentration in lotion is3.3g/L, in10hours crude oil elution efficiency can reach43.31%. Efficiency improved with blending a little amount of chemical surfactant.When blend1.67g/L rhamnolipid A and1.67g/L rhamnolipid B and0.05g/LTween60, in10hours crude oil elution rate ups to91.26%, increased50%. Because ofrhamnolipid is easy to biodegradable, and joined only0.05g/L chemical surfactent inthe eluent, for oil eluen improving the possibility that follow-up oil contaminationdegrading rapidly.