title: A preparative method for the purification of isopenicillin N from genetically blocked Acremonium chrysogenum strain TD189: studies on the degradation kinetics and storage conditions.
abstract: A protocol for preparative isopenicillin N (IPN) purification, a highly interesting and hitherto unavailable intermediate of the penicillin and cephalosporin biosynthetic pathway due to its high unstability, is described. Culture broths of Acremonium chrysogenum TD189, a strain blocked in cephalosporin biosynthesis that accumulates this metabolite, were treated with acetone and filtered though charcoal and a hydrophobic resin in a single step as tandem columns. The cleared broth was then lyophilized and passed though a Sephadex G-25 column. The last step was the purification to homogeneity of IPN in a semipreparative HPLC equipment and, optionally, a desalting step by Sephadex G-10 column. Once purified, a complete analysis of the stability of the compound and the conditions for its long-term storage was carried out. Our results suggest a first-order model for IPN decomposition for all the pH and temperature analyzed. IPN is more stable at neutral pH, and once lyophilized, can be stored under vacuum and -75 ° C with a half-life of 770 days.
authors.affiliation: Instituto de Biotecnología (INBIOTEC), Parque Científico de León, León, Spain. inmavaca@uchile.cl
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Vaca
authors.forename: Javier
authors.initials: J
authors.lastname: Casqueiro
authors.forename: Ricardo V
authors.initials: RV
authors.lastname: Ullán
authors.forename: Angel
authors.initials: A
authors.lastname: Rumbero
authors.forename: Renato
authors.initials: R
authors.lastname: Chávez
authors.forename: Juan F
authors.initials: JF
authors.lastname: Martín
mesh_terms: D000164:Acremonium / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003470:Culture Media; D004355:Drug Stability; D004356:Drug Storage; D005612:Freeze Drying; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D010406:Penicillins / Q000737:chemistry / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D003470:Culture Media; D010406:Penicillins; C006414:penicillin N