title: Optimizing iron supplement strategies for enhanced surfactin production with Bacillus subtilis.
abstract: Supplement of Fe(2+) into fermentation medium was utilized as a tool to optimize the iron-mediated enhancement of surfactin production from Bacillus subtilis ATCC 21332. Up to 3000 mg L(-)(1) of surfactin was produced using an iron-enriched minimal salt (MS) medium amended with an optimal Fe(2+) dosage of 4.0 mM, leading to 8-fold and 10-fold increase in cell concentration and surfactin yield, respectively, as compared to those without Fe(2+) supplement. In addition to resulting in an optimal production yield of surfactin, a supplement of 4.0 mM of Fe(2+) also propelled maximum overall surfactin production rate to a highest value of 24 mg L(-)(1) h(-)(1). Our results also show that production of surfactin followed a growth-associated kinetic model. The best yield coefficient estimated from the model was ca. 162 mg surfactin (g dry cell)(-)(1). The supernatant of the iron-enriched culture of B. subtilis ATCC 21332 exhibited the ability to emulsify kerosene and achieved a maximum emulsion index (E(24)) of 80% for culture supplemented with 4.0 mM of Fe(2+). Comparison of emulsion index and the corresponding surfactin production indicates that the emulsification activity was essentially contributed by surfactin.
authors.affiliation: Graduate School of Biotechnology and Bioinformatics, Yuan Ze University, Taoyuan, Taiwan.
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Wei
authors.forename: Li-Fen
authors.initials: LF
authors.lastname: Wang
authors.forename: Jo-Shu
authors.initials: JS
authors.lastname: Chang
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects* / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D003470:Culture Media / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007501:Iron / Q000493:pharmacokinetics* / Q000494:pharmacology*; D055666:Lipopeptides; D010456:Peptides, Cyclic / Q000096:biosynthesis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003470:Culture Media; D055666:Lipopeptides; D010456:Peptides, Cyclic; C009365:surfactin peptide; D007501:Iron