Saccharopolyspora erythraea-catalyzed bioconversion of 6-deoxyerythronolide B analogs for production of novel erythromycins

• Published in: Journal of biotechnology 2002-01, Vol.92 (3), p.217-228
• Main Authors: Carreras, Christopher, Frykman, Scott, Ou, Sally, Cadapan, Lawrence, Zavala, Stefan, Woo, Elaine, Leaf, Timothy, Carney, John, Burlingame, Mark, Patel, Sajel, Ashley, Gary, Licari, Peter
• Format: Article
• Language: English
• Subjects: 6-deoxyerythronolide B; Bioconversion; Biological and medical sciences; Bioreactors; Biotechnology; Biotransformation; Culture Media; Erythromycin; Erythromycin - analogs & derivatives; Erythromycin - biosynthesis; Erythromycin - chemistry; Erythromycin - metabolism; Fundamental and applied biological sciences. Psychology; Kinetics; Molecular Structure; Multienzyme Complexes - genetics; Multienzyme Complexes - metabolism; Mutation; Plasmids - genetics; Polyketide synthase; S. erythraea; Saccharopolyspora - metabolism; Saccharopolyspora erythraea; Streptomyces - genetics; Streptomyces - metabolism
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/S0168-1656(01)00372-8

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.