title: Optimization of surfactin production by Bacillus subtilis isolate BS5.
abstract: Bacillus subtilis BS5 is a soil isolate that produces promising yield of surfactin biosurfactant in mineral salts medium (MSM). It was found that cellular growth and surfactin production in MSM were greatly affected by the environmental fermentation conditions and the medium components (carbon and nitrogen sources and minerals). Optimum environmental conditions for high surfactin production on the shake flask level were found to be a slightly acidic initial pH (6.5-6.8), an incubation temperature of 30 degrees C, a 90% volumetric aeration percentage, and an inoculum size of 2% v/v. For media components, it was found that the optimum carbon source was molasses (160 ml/l), whereas the optimum nitrogen source was NaNO(3) (5 g/l) and the optimum trace elements were ZnSO(4).7H(2)O (0.16 g/l), FeCl(3).6H(2)O (0.27 g/l), and MnSO(4).H(2)O (0.017 g/l). A modified MSM (molasses MSM), combining the optimum medium components, was formulated and resulted in threefold increase in surfactin productivity that reached 1.12 g/l. No plasmid could be detected in the tested isolate, revealing that biosurfactant production by B. subtilis isolate BS5 is chromosomally mediated but not plasmid-mediated.
authors.affiliation: Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
authors.forename: A Mohammad
authors.initials: AM
authors.lastname: Abdel-Mawgoud
authors.forename: M Mabrouk
authors.initials: MM
authors.lastname: Aboulwafa
authors.forename: Nadia Abdel-Haleem
authors.initials: NA
authors.lastname: Hassouna
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects* / Q000378:metabolism*; D002412:Cations / Q000494:pharmacology; D003470:Culture Media / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D055666:Lipopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008320:Maltose / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013012:Sorbitol / Q000494:pharmacology; D013395:Sucrose / Q000494:pharmacology; D013501:Surface-Active Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013696:Temperature
chemical_list: D000596:Amino Acids; D002412:Cations; D003470:Culture Media; D055666:Lipopeptides; D009566:Nitrates; D010456:Peptides, Cyclic; D013501:Surface-Active Agents; C009365:surfactin peptide; D013012:Sorbitol; D013395:Sucrose; D008320:Maltose; C031618:sodium nitrate; D005947:Glucose