In the present article the theoretical calculation of thermodynamic parameters for the two main precipitation agents, potassium 2-ethylhexanoate and t-octylamine, employed by the pharmaceutical industry to obtain potassium clavulanate for clinical use, is described. The results obtained using the standard thermochemistry calculation in the Gaussian package and by calculation of the reactivity indexes of the reagents and products are compared. The calculated thermodynamic parameters indicate that the reactivity indexes present a better correlation with the experimentally obtained percentage yield. In addition, a series of additional precipitation agents that are also used in industrial procedures to obtain potassium clavulanate for clinical use, were compared. This was done to verify if any present, a priori, better properties than potassium 2-ethylhexanoate or t-octylamine. The consistency of the reactivity indexes calculated clearly suggests that the methodology employed can be used to screen future precipitation agents for possible use in the production of potassium clavulanate.
Background: The aim of this study was the production of xanthan gum from salts of volatile fatty acids, which can be generated in anaerobic processes for the production of hydrogen from organic wastewaters. Xanthan gum was produced with three different acid salts used to replace the traditional citrate, which is normally used in the culture for the production of this biopolymer. The volatile fatty acids (VFA) salts used were sodium acetate 0.0328 M, sodium propionate 0.0219 M, and sodium butyrate 0.0164 M. Results: The values of biomass yield, (Yp/x) obtained were 9.2 g/g for acetate, 11.78 g/g for citrate, 11.80 g/g for butyrate and 14.59 g/g for propionate, while the values of the product yield (Yp/s), were 0.92; 0.59; 0.71 and 0.72 for acetate, citrate, butyrate and propionate. As for the rheological characterization, the gums produced showed a consistency index (K) and flow index (n) of 9.8 dina.s-n.cm-2 and 0.34 for acetate; 6.3 dina.s-n.cm-2 and 0.39 for citrate, 5.8 dina.s-n.cm-2 and 0.45 for butyrate, 39.2 dina.s-n.cm-2 and 0.24 for propionate, that characterize the gums with good consistency and fluidity. Conclusions: It is possible to produce xanthan gum from short-chain volatile acids in replacement by the citrate that is usually used in medium composition for the gum production. These results contribute to the feasibility studies for implementation of processes for treating wastewater generating products such as volatile acids, hydrogen and consequent use of these acids for the production of xanthan gum.
The present article reviews different aspects of the chemistry of two widely used β-lactam antibiotics Clavulanic Acid and Cephamycin C. The article discusses important details of the biosynthesis of these compounds, their action mechanism and, principally, the methods employed in their isolation and purification, in accordance with the available literature. Despite the large quantity of available articles and patents concerning β-lactam antibiotics, those which describe the isolation and purification of Clavulanic Acid and Cephamycin C are rare. Overall, the intention of this article is to discuss the up-to-date scientific research related to the compounds under review.