title: Effect of medium components and culture conditions in Bacillus subtilis EA-CB0575 spore production.
abstract: Bacillus subtilis spores have important biotechnological applications; however, achieving both, high spore cell densities and sporulation efficiencies in fermentation, is poorly reported. In this study, medium components and culture conditions were optimized with different statistical methods to increase spore production of the plant growth promoting rhizobacteria B. subtilis EA-CB0575. Key medium components were determined with Plackett-Burman (PB) design, and the optimum concentration levels of two components (glucose, MgSO4·7H2O) were optimized with a full factorial and central composite design, achieving 1.37 × 10(9) CFU/mL of spore cell density and 93.5 % of sporulation efficiency in shake flask. The optimized medium was used to determine the effect of culture conditions on spore production at bioreactor level, finding that maintaining pH control did not affect significantly spore production, while the interaction of agitation and aeration rates had a significant effect on spore cell density. The overall optimization generated a 17.2-fold increase in spore cell density (8.78 × 10(9) CFU/mL) and 1.9-fold increase in sporulation efficiency (94.2 %) compared to that of PB design. These results indicate the potential of B. subtilis EA-CB0575 to produce both, high spore cell densities and sporulation efficiencies, with very low nutrient requirements and short incubation period which can represent savings of process production.
authors.affiliation: Grupo de Investigación en Ciencias Biológicas y Bioprocesos (CIBIOP), Department of Process Engineering, Universidad EAFIT, Cra. 49 # 7 Sur-50, Medellín, Antioquia, Colombia.|Centro de Investigaciones del Banano-AUGURA, Carepa, Colombia.
authors.forename: Luisa F
authors.initials: LF
authors.lastname: Posada-Uribe
authors.affiliation: Universidad Nacional de Colombia, Calle 59A # 63-20, Medellín, Antioquia, Colombia.
authors.forename: Magally
authors.initials: M
authors.lastname: Romero-Tabarez
authors.affiliation: Grupo de Investigación en Ciencias Biológicas y Bioprocesos (CIBIOP), Department of Process Engineering, Universidad EAFIT, Cra. 49 # 7 Sur-50, Medellín, Antioquia, Colombia. vvilleg2@eafit.edu.co.
authors.forename: Valeska
authors.initials: V
authors.lastname: Villegas-Escobar
mesh_terms: D001412:Bacillus subtilis / Q000145:classification / Q000166:cytology / Q000502:physiology*; D061249:Batch Cell Culture Techniques / Q000379:methods*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation / Q000502:physiology; D003470:Culture Media / Q000378:metabolism*; D013045:Species Specificity; D013171:Spores, Bacterial / Q000166:cytology / Q000254:growth & development*
chemical_list: D003470:Culture Media
keywords: Bacillus subtilis; Bacterial culture optimization; Spore production; Sporulation efficiency