Saccharopolyspora erythraea-catalyzed bioconversion of 6-deoxyerythronolide B analogs for production of novel erythromycins.
A method was developed for the large-scale bioconversion of novel 6-deoxyerythronolide B (6-dEB) analogs into erythromycin analogs. Erythromycin biosynthesis in Saccharopolyspora erythraea proceeds via the formation of a polyketide aglycone, 6-dEB, which is subsequently glycosylated, hydroxylated and methylated to yield the antibiotic erythromycin A. A modular polyketide synthase (PKS) directs 6-dEB synthesis using a dedicated set of active sites for the condensation of each of seven propionate units. Strategies based on genetic manipulation and precursor feeding are available for the efficient generation of novel 6-dEB analogs using a plasmid-based system in Streptomyces coelicolor. 6-dEB and 13-substituted 6-dEB analogs produced in this manner were fed to S. erythraea mutants which could not produce 6-dEB, yet retained their 6-dEB modification systems, and resulted in the generation of erythromycin A and 13-substituted erythromycin A analogs. Erythromycin B, C and D analogs were observed as intermediates of the process. Dissolved oxygen, temperature, the specific aglycone feed concentration, and pH were found to be important for obtaining a high yield of erythromycin A analogs. Cultivation conditions were identified which resulted in the efficient bioconversion of 6-dEB analogs into erythromycin A analogs, which this process demonstrated at the 100 l scale.
Carreras
Christopher
C
Department of Process Science, Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, CA 94545, USA.
Frykman
Scott
S
Ou
Sally
S
Cadapan
Lawrence
L
Zavala
Stefan
S
Woo
Elaine
E
Leaf
Timothy
T
Carney
John
J
Burlingame
Mark
M
Patel
Sajel
S
Ashley
Gary
G
Licari
Peter
P
D019149:Bioreactors; D001709:Biotechnology; D001711:Biotransformation; D003470:Culture Media; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D015394:Molecular Structure; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D016930:Saccharopolyspora / Q000378:metabolism*; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism
D003470:Culture Media; D009097:Multienzyme Complexes; C034277:6-deoxyerythronolide B; D004917:Erythromycin