title: Enhanced production of mosquitocidal cyclic lipopeptide from Bacillus subtilis subsp. subtilis.
abstract: OBJECTIVE
  A cyclic lipopeptide, surfactin produced by a strain of Bacillus subtilis subsp. subtilis (VCRC B471) was found to exhibit activity against both the larval and pupal stages of mosquitoes. The present study was aimed at increasing the production of the mosquitocidal metabolite by modifying the conventional medium.
  
  
  METHODS
  Enhancement of mosquitocidal metabolite production was attempted by replacing the existing micronutrients of the conventional NYSM and supplementing the medium with additional amounts of glucose. The LC₅₀ value of culture supernatant (CS) against the larval and pupal stages of Anopheles stephensi was determined. Crude mosquitocidal metabolite (CMM) was separated from the CS, identified by MALDI-TOF analysis and its LC₅₀ dosage requirement for the pupal stage of the above mosquito species determined.
  
  
  RESULTS
  The medium containing a new composition of micronutrients and glucose up to 1 per cent resulted in increased metabolite production. The LC₅₀ value of the CS obtained in the improved medium against larvae and pupae of An. stephensi was 5.57 and 0.71 μl/ml, respectively. The yield of CMM was doubled in the improved medium. MALDI-TOF analysis revealed that the CMM was surfactin.
  
  
  CONCLUSIONS
  The new improved medium enhanced the production of mosquitocidal metabolite as the dosage required for inciting 50 per cent mortality among the pupal stages of mosquitoes was only half of that required when the metabolite was produced in the conventional medium. The mosquitocidal metabolite was identified as surfactin, a cyclic lipopeptide and biosurfactant.
authors.affiliation: Vector Control Research Centre (ICMR), Puducherry, India. ammanonmani@yahoo.com
authors.forename: A M
authors.initials: AM
authors.lastname: Manonmani
authors.forename: I
authors.initials: I
authors.lastname: Geetha
authors.forename: S
authors.initials: S
authors.lastname: Bhuvaneswari
mesh_terms: D000818:Animals; D001412:Bacillus subtilis / Q000254:growth & development* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology; D009033:Culicidae / Q000187:drug effects*; D003470:Culture Media / Q000737:chemistry; D006801:Humans; D007306:Insecticides; D055666:Lipopeptides / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D007306:Insecticides; D055666:Lipopeptides; D010456:Peptides, Cyclic; C524483:cyclic lipopeptide, Bacillus subtilis
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