Separation Of Lysine From Fermentation Broth By Solvent Extraction

The article discusses the general production and separation techniques of aminoacid and focuses on the progress of lysine production by fermatation method andseparation by extraction method. A simple, convenient and reliable analysis methods oflysine fermentation is established, which is supplied by factory. Reactive extractionprocess and saponification extraction mechanism are studied using P2or P5as theextraction agent and sulfonated kerosene as diluent. The effect of extractantcomposition, reaction time, temperature, O/W （V/V）, the initial concentration of lysine,the pH of aqueous phase and saponification ratio on extraction ratio or distributioncoefficient is researched by univariate experiment. The study has found that the reactionreaches equilibrium with the stir speed200r/min for4minutes. The reaction enthalpyof extraction process is-2.61kJ/mol and the extraction is exothermic that extractionequilibrium constant Kexdecreases with the increase of temperature. Meanwhile, theextraction can be reacts at room temperature. Based on the dissociation equilibrium ofamino acids in aqueous solutions and equilibrium constants, the lysine distributionpattern is studied in aqueous solution at different pH values. And the lysine monovalentcations and divalent cations are involved in the reaction through the extraction rate atdifferent pH, but monovalent cations are main.Using1.50mol/L P5which saponification ratio is50.00%and90g/L fermentationbroth at25℃in5min，single-stage extraction ratio achieves about45.00%byunivariate experiment. The extraction rate can exceed99.10%by eight-stagecountercurrent extraction. The stripping can be quickly with hydrochloric acid asstripping agent, the stripping ratio exceeds99.80%with the stir speed of200r/min in4minutes, when the concentration of hydrochloric acid is0.60mol/L and O/W（V/V） is1:1.The article studies the effect of stir speed, temperature, phase boundary area, theinitial concentration of lysine, the concentration of P5on the extraction velocity and themass transfer coefficient, and calculates out the activation energy of extraction reaction12.00kJ/mol, and the extraction reaction rate equation is R=0.0074[HL]^2.08[A]^1.03.Meanwhile, by studying the effect of various factors on mass transfer coefficient, the relationship of mass transfer coefficient with speed meets to the equation K=1.61×10^-6n+6.06×10^-5, and the relationship of mass transfer coefficient with temperature meetsto the equation K=1.67×10^-5T-0.0044. The extraction process is a mixing controlmode，which is controlled by the chemical reaction rate and mass transfer rate withinthe stir speed of50-130r/min, and the mass transfer resistance is arised from theorganic phase mainly. The main mass transfer substances are extracted complexproduced by extractant anionic and lysine cationic.