Separation of clavulanic acid from fermented broth of amino acids by an aqueous two-phase system and ion-exchange adsorption

The clavulanic acid is a substance which inhibits the β-lactamases used with penicillins for therapeutic treatment. After the fermentation, by-products of low molecular weight such as amino acids lysine, histidine, proline and tyrosine are present in the fermented broth. To remove these impurities the techniques of extraction by an aqueous two-phase system of 17% polyethylene glycol molecular weight 600 and 15% potassium phosphate were used for a partial purification. A subsequent ion-exchange adsorption was used for the recuperation of the clavulanic acid of the top phase and purification getting a concentration factor of 2 and purification of 100% in relation to the amino acids lysine, histidine, proline and tyrosine.

Evaluation of the effects of the parameters involved in the purification of clavulanic acid from fermentation broth by aqueous two-phase systems

The purification of clavulanic acid (CA), which is an important beta-lactam antibiotic produced by submerged cultivation of Streptomyces clavuligerus, was studied through the use of phosphate and polyethylene glycol-based aqueous two-phase systems. The parameters' effect on the yield and purification was evaluated through an experimental design and the preliminary results showed that the polyethylene molecular mass and tie-line length and phase volume ratio exerted the strongest effect on the yield and distribution coefficient in the range tested. In addition, the response surface methodology was used to optimize the distribution coefficient, yield, and purification factor. The optimal conditions of yield and purification factor are in the regions where polyethylene has a low molecular mass, pH close to the isoelectric point, and lower top phase volume. A 100% yield and a 1.5-fold purification factor are obtained when extracting CA by maximizing the conditions of an aqueous two-phase system.

Ionic liquids as advantageous solvents for headspace gas chromatography of compounds with low vapor pressure

The potential of ionic liquids as solvents for headspace gas chromatography was investigated. Three compounds with boiling points above 200 degrees C were selected to demonstrate the feasibility of the concept described. 2-Ethylhexanoic acid, formamide, and tri-n-butylamine as examples of acidic, neutral, and basic analytes were dissolved in acidic 1-n-butyl-3-methylimidazolium hydrogen sulfate (1), neutral 1-n-butyl-2,3-dimethylimidazolium dicyanamide (2), and 2 containing 1,8-diazabicyclo[5.4.0]undec-7-ene to adjust basic conditions. All analytes could be determined with limits of detection and limits of quantification in the low-ppm concentration range.

Continuous clavulanic acid adsorption process

Adsorption kinetics and equilibrium data of clavulanic acid, a beta-lactam antibiotic, on ion-exchange resin Amberlite IRA 400 were utilized to carry out the modeling and simulation of a continuous adsorption process. These simulations allowed the estimation of yield, concentration, and purification factors of the process utilizing the product final concentration. Experimental runs of this process were carried out using the conditions pointed out by simulation studies. Comparison of the experimental results and those calculated by the proposed model showed that the model could describe very well the main features of the continuous process.

Kinetic studies of clavulanic acid recovery by ion exchange chromatography

Clavulanic acid (CA) is a beta-lactamase inhibitor produced by strains of Streptomyces clavuligerus. Nowadays, the combination of CA with amoxycillin is the most successful example of the use of a beta-lactam antibiotic sensitive to beta-lactamases together with an inhibitor of these enzymes. Clavulanic acid is purified from fermentation broth by a series of steps consisting mainly of two-phase separation processes such as liquid-liquid extraction, adsorption or ion-exchange chromatography, among others. Amberlite IRA 400, a strong anion-exchange resin, has a very high adsorption capacity for CA (Mayer et al. 1997). This resin can be pre-treated with NaCl (chloride cycle), to remove selectively only those anions, which are able to displace chloride from the resin or with NaOH (hydroxyl cycle), to remove all species of anions. In order to decide the best operating conditions for CA recovery by ion-exchange resins and then to construct a model of this separation process, batch experiments were conducted using Amberlite IRA 400 in the chloride cycle. These runs were carried out in a 200 ml stirred tank, at two different initial solution pH, 6.2 and 4.0; the temperature was maintained at 10 degrees C and 20 degrees C during adsorption and 30 degrees C during the desorption step. It was possible, on the basis of these batch results, to model the separation process, including the adsorption kinetics, equilibrium data and mass transfer limitations.

Removal of the fermentation by-product succinylL-tyrosine from the ?-lactamase inhibitor clavulanic acid using a molecularly imprinted polymer

Clavulanic acid is a beta-lactamase inhibitor used in therapeutic combinations with the penicillin-type antibiotics. During the fermentation leading to clavulanic acid, a succinyl L-tyrosine by-product is unavoidably formed. Occasionally, the amount of this by-product is found to be as high as 2% of the product even after standard purification operations. To further remove this impurity, we prepared a highly specific adsorbent for succinyl L-tyrosine with the molecular imprinting technique. This was performed by simultaneously using vinylbenzyl trimethylammonium chloride and methacrylic acid as the functional monomers. The imprinted polymer selectively bound succinyl L-tyrosine, and could be successfully used to remove this impurity at concentrations of less than 2% in the presence of clavulanic acid.