Preliminary Studies for Cephamycin C Purification Technique

A study was made for purification of cephamycin C from fermentation of Streptomyces clavuligerus. Initially, the culture broth was clarified by microfiltration and ultrafiltration, after which the resulting permeates were subjected to nonspecific adsorption and ion-exchange chromatography on resin columns. The antibiotic activity was measured by the biological method at each stage by assaying its activity against the Escherichia coli ESS, super sensitive to β-lactam antibiotic. The purification processes were assessed in relation to the variables affecting each step. The purification efficiency by nonspecific adsorption was monitored by UV spectrophotometry, while the ion-exchange adsorption fractions were assessed by NMR spectroscopy. Some of the fractions obtained during purification were also analyzed by mass spectrometry (LC/MS and LC/MS/MS) to identify the cephamycin C molecule. These preliminary results proved the process feasibility.     

Synthesis and characterization of polymer-protected rhodium and palladium sols in mixed media

A series of polymer-protected rhodium and palladium sols were generated in mixed (organic/aqueous) dispersion media. Protecting polymers used were PAA, PVP, PVA and an oligosaccharide-based protecting agent, arabinogalactan. This is the first systematic study of colloids generated in mixed solvent dispersion media with these protecting agents. The sols were characterized by TEM, UV/Vis spectrophotometry and Photon Correlation Spectroscopy (PCS). In general, the macroscopic stability of the sols depended on the protecting agent/organic cosolvent combination used, with a nonlinear dependence on cosolvent concentration. Observed sol stabilities correlated well with pre-existing hydrodynamic data for the protective polymers, e.g. radius of gyration data. Average particle size and polydispersity of all sols examined decreased as cosolvent concentration increased, with actual cosolvent concentration, protecting agent and reducing agent used influencing the extent of decrease. Sol particle sizes ranged from 0.8 nm to 6.0 nm with sol turbidities decreasing in parallel with the particle sizes. Hydrodynamic sizes (from PCS) tended to reflect the sols' macroscopic stabilities. FTIR studies using adsorbed CO as a spectroscopic surface probe indicated decreases in the ν(CO)(ads) stretching frequency with an increase in cosolvent concentration due to competitive adsorption of CO with the cosolvent molecules on the metal colloid surfaces.