| Lincomycin, which is a type of high active and broad spectrum antibiobtic, has been used for the clinical treatment of osteomyelitis for its penetrability in tissues and cells. Presently, extraction is an accepted method in the extracting process of lincomycin from fermented broth in industry for its low cost and simpleness operation. In this paper, according to the properties of lincomycin, method of measurement of lincomycin concentration in broth was constructed, extracting capability of different solvents was researched, the method of extracting lincomycin by multi-extractant was put forward, a new binary-extractant fitting for extracting lincomcy was found and optimized, extracting technology was studied, and thermodynamics parameters was calculated. UNIFAC group-contribution method was applied in lincomycin extraction system, macro-molecule system, and group interaction parameters was complemented according to experimental data. Phase graph was drawed for multi-extraction system.1.Method of measurement of lincomycin concentration. Effect on rotation-measurement of lincomycin concentration was studied. And the method of measurement of lincomycin concentration in fermented broth by spectrophotometry was established, which was used palladium chloride as color reagent. Optimum measured wavelength is 380nm, reaction time is 30min, and dosage of color reagent is 0.5ml which concentration is 0.02mol/l measuring 0.5ml fermented broth. In the range of 20-300u/ml, absorbency and lincomycin concentration has linear relation.2.Extraction of lincomycin by binary-extractant. Extractant B-S, mellow solvent, has higher extraction ability than others. Distribution coefficient of lincomycin in it is twice times as much as it in n-butanol, and solubility of it is twice and a half times as low as n-butanol's. Optimum volume fraction of extractant B in binary-extractant is 60%-80%, and the highest cooperate coefficient is 1.28, which exists in this range. Besides that, this binary-extractant also has characters of stabilization, low toxicity, low volatilization and facile in industry.3.Optimization of extraction technology. Optimum conditions of extraction of lincomycinby binary-extractant is: aqueous pH 10.6, ratio of phase (O/A) 2:1, volume fraction of extractant B 65%, temperature 35℃. Stripping process can be achieved whose pH of stripping water is lower than 2.0, and stripping extraction is higher than 95%. In the same condition, extraction of extracting lincomycin in fermented broth decreases as little as 2% contrasting with it in aqueous solution. Coefficients of solvation are 1.79 and 0.89 (for extractant B,S), and constant of extraction equilibrium is 5.194, △Hm is 12.96kJ/mol, △Gmis - 13.306kJ/mol, △Sm is 85.24kJ/mol.4.Application of UNIFAC group-contribution method 44 interaction group-parameters of 9 sub - groups was fitted for complementing the parameters of UNIFAC--r∞. Equilibrium coefficient of lincomycin was calculated by UNIFAC method according to the literature data and fitted data. Error of value is less than 30% compared with experimental ones expect one or two, which can meet the needs of the engineering calculation. The method was even used for reckoning other systems' equilibrium coefficient. The precision was satisfied, and error is less than 30% , too.5.Painting of phase graph for multi-component. Phase graphs were drawed which described the relation between concentration of lincomycin in extractant and raffinate and volume of extractant in different temperatures. In phase graph, some rules is learned, which slope of equilibrium of curves is decrease with the increase of volume fraction of extractant B, that is the ratio of concentration of lincomycin in extractant and in raffinate gradually increasing, and extraction was so.
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