title: [Study on the screening of lactamase and its fermentation conditions].
abstract: (-)-gamma-Lactam is one of the key starting materials for the synthesis (-)-cabovir and (-)-abacavir, which serve as two powerful antiviral agents. The production of gamma-lactam using enzymatic resolution of racemic gamma-lactam was attempted in the paper. 20 out of 69 strains capable of producing lactamase were screened from soil samples collected in several districts throughout Beijing; particularly N-actylphenylalanine was used as sole carbon source in the screening method. It was found by chiral HPLC analysis that strain L29-9 was able to enantioselectively hydrolyze the (+)-isomer in the racemic lactam, thus giving the desired (-)-gamma-lactam with high enantiomeric excess (> 70%). Ferment conditions of strain L29-9, including carbon source, nitrogen source, pH, and culturing time, were studied and the optimum conditions were as follows: citric acid 2 g/L, yeast extract 5 g/L, pH 7.0, culturing for 40h. Biotransformation using whole cells of the strain was inducted at 30 degrees C for 12h, giving (-)-gamma-lactam as enantiopure product with yield up to 40% and 99.5% e.e.
authors.affiliation: Department of Pharmaceutical Engineering, Beijing University of Chemical Technology, Beijing 100029, China. lih928@163.com
authors.forename: Hai-quan
authors.initials: HQ
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Su
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.forename: Jian-jun
authors.initials: JJ
authors.lastname: Wang
authors.forename: Guo-jun
authors.initials: GJ
authors.lastname: Zheng
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007769:Lactams / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D007769:Lactams; D000581:Amidohydrolases; C401943:gamma-lactamase