[The effects of Vitreoscilla hemoglobin expression on growth and antibiotic production in Streptomyces cinnamonensis].

Streptomyces cinnamonensis A-10 is a monensin \ producing strain. pHZ1252 is an E. coli-Streptomyces shuttle vector for expressing VHb, in which vhb structural gene is controlled by thiostrepton-inducible promoter PtipA. pHZ1252 was unstable in S. cinnamonensis, occurring deletion recombination. The deletion DNA fragment of pHZ1252 included not only part of E. coli plasmid but also vhb gene. However, plasmid pHZ1252 isolated from S. avermitilis transformants, which lost part of E. coli plasmid but still contained vhb gene and PtipA was stable in S. cinnamonensis and expressed VHb with biological activity after thiostrepton induction. Shake flask fermentation experiments showed that the presence of VHb in S. cinnamonensis efficiently enhanced cell growth and improved antibiotic production under aeration-poor conditions.