| 摘要 |
Important intermediates for preparing cephalosporin antibiotics, 7-amino-cephalosporanic acid (7-ACA) and 7-aminodeacetylcephalosporanic acid (7-ADAC), are prepared by a novel bioprocess in which a transformed Penicillium chrysogenum strain is cultured in the presence of an adipate feedstock to produce adipoyl-6-APA (6-amino penicillanic acid); followed by the in situ expression of the following genes with which the P. chrysogenum has been transformed: 1) an expandase gene, e.g., from Cephalosporium acremonium, whose expression product converts the adipoyl-6-APA by ring expansion to adipoyl-7-ADCA; 2) an hydroxylase gene whose expression product converts the 3-methyl side chain of adipoyl-7-ADCA to 3-hydroxymethyl, to give the first product, 7-aminodeacetylcephalosporanic acid (7-ADAC); and 3) an acetyltransferase gene whose expression product converts the 3-hydroxymethyl side chain to the 3-acetyloxymethyl side chain of 7-ACA. The final product, 7-ACA, is then prepared by cleavage of the adipoyl side chain using an adipoyl acylase. The entire synthesis, accordingly, is carried out using bioprocesses, and is efficient and economical. n |
