title: Improvement of a two-stage fermentation process for docosahexaenoic acid production by Aurantiochytrium limacinum SR21 applying statistical experimental designs and data analysis.
abstract: Statistical screening experimental designs were applied to identify the significant culture variables for biomass production of Aurantiochytrium limacinum SR21 and their optimal levels were found using a combination of Artificial Neural Networks, genetic algorithms and graphical analysis. The biomass value obtained (40.3g cell dry weight l(-1)) employing the selected culture conditions agreed with that predicted by the model. Subsequently, two significant culture conditions for docosahexaenoic acid (DHA) production were determined, finding that an inoculum of 10% (v/v), obtained from the previous (statistically optimized) stage, should be used in a DHA production medium having a molar C:N ratio of 55:1, to reach a production of 7.8 g DHA l(-1) d(-1). The production step was thereafter scaled in a 3.5l bioreactor, and DHA productivity of 3.7 g l(-1) d(-1) was obtained. This two-stage strategy: statistically optimized inoculum production (fist step) and a DHA production step, is presented for the first time to optimize a bioprocess conducive to the obtention of microbial DHA.
authors.affiliation: Instituto de Investigaciones Biotecnológicas, IIB-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina.
authors.forename: Silvina Mariana
authors.initials: SM
authors.lastname: Rosa
authors.forename: Marcelo Abel
authors.initials: MA
authors.lastname: Soria
authors.forename: Carlos Guillermo
authors.initials: CG
authors.lastname: Vélez
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Galvagno
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D003470:Culture Media; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D056890:Eukaryota / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology*; D015233:Models, Statistical; D015203:Reproducibility of Results; D013223:Statistics as Topic
chemical_list: D003470:Culture Media; D004281:Docosahexaenoic Acids