Construction Of Gentamicin B Overproducing Strain By Gene Combination Biosynthesis And Metabolic Engineering

With the development of genetic engineering technology,people have a more deeper understand about the aminoglycoside antibiotics.The researchers pay more attention to the semi-synthetic aminoglycoside antibiotics with weakly toxic but highly active recent years.Gentamicin B as a 2-DOS aminoglycoside antibiotics,is the raw materials of isopramine.The gentamicin B overproducing strain is a great significance to industrial production.The biosynthetic pathway of gentamicin has been elucidated,GenK and GenP were methylationase and phosphotransferase respectively.In this study,We generated a strain overproducing JI-20A by disrupting genK and genP.JI-20A can be transformed into gentamicin B through oxidation and deamination.kanJ and kanK were integrated in the genome of overproducing JI-20A strain with four different promoters.Finally we generated the gentamicin B overproducing strain.Then the glycosyltr ansferases KanMl and GenM2 were also overexpressed in gentamicin B overproducing strain during glucose feeding.The production of gentamicin B further improved.Overproducing gentamicin C1a strain was constructed by our lab formerly,which is used as starting strain in this study.The kanMl and genM2 were overexpressed in starting strain during glucose feeding.The production of gentamicin Cl a improved even more.The establishment of the overexpression system of the glycosyltransferase KanMl and GenM2 in M.echinospora realized the transformation from primary metabolism to secondary metabolism,it provided a realistic of switching the metabolic flux in cell.Also demonstrate that modulate the enzymes transfer primary metabolismin to secondary metabolism can be used to switch more metabolic flux into the biosynthetic pathway of trget products.