title: Enhancement of avermectin and ivermectin production by overexpression of the maltose ATP-binding cassette transporter in Streptomyces avermitilis.
abstract: We investigated the function of maltose ABC transporter system encoded by malEFG-a and the effect of its overexpression on antibiotic production in Streptomyces avermitilis. A malEFG-a deletion mutant was unable to grow in a minimal medium with maltose as sole carbon source and produce avermectin. Maltose utilization and avermectin production were restored by introduction of a single copy of malEFG-a. RT-PCR analysis showed that the expression of malE-a was induced by maltose, and was strongly repressed by glucose. When multi-copy, integrative malEFG-a gene expression vectors were introduced into wild-type strain ATCC31267 and ivermectin-producer OI-31, antibiotic production increased by 2.6- to 3.3-fold and the time required for fermentation decreased by about 10%. The overexpression of malEFG-a improved the utilization rate of starch, and thereby enhanced avermectin production. Such an approach would be useful for the improvement of commercial antibiotic production using starch as the main carbon source in the fermentation process.
authors.affiliation: State Key Laboratories for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Song
authors.forename: Ying
authors.initials: Y
authors.lastname: Wen
authors.forename: Jilun
authors.initials: J
authors.lastname: Li
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D002244:Carbon / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000378:metabolism*; D008320:Maltose / Q000378:metabolism*; D009840:Oligomycins / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013213:Starch / Q000378:metabolism; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D003470:Culture Media; D009840:Oligomycins; D012333:RNA, Messenger; D008320:Maltose; D007559:Ivermectin; C019264:avermectin; D002244:Carbon; D013213:Starch