title: High-cell-density cultivation of Schizochytrium sp. in an ammonium/pH-auxostat fed-batch system.
abstract: Thraustochytrids, in particular Schizochytrium spp., are used for the production of the valuable polyunsaturated fatty acid, docosahexaenoic acid (DHA; 22:6 n-3). Growth of Schizochytrium sp. G13/2S in a defined medium was initially made in shake-flask cultures to determine the optimum concentrations of glucose (100-200 g l(-1)) and ammonia ( approximately 300 mg l(-1)) that could be used by this microorganism. In subsequent fermenter cultures, a pH-auxostat method was used to maintain NH(3) from 200-300 mg l(-1). During the first 49 h of fermentation, 150 g glucose l(-1) produced 63 g cell dry wt l(-1). Although growth was not limited by the supply of nitrogen, total fatty acids were at 25% cell dry wt which is more than half the final lipid content of commercially-grown Schizochytrium biomass which uses N-limited medium in the final stages for maximum lipid accumulation. This strategy is therefore useful for the cultivation of Schizochytrium to a high cell density up to the point when lipid accumulation can be triggered by N exhaustion.
authors.affiliation: Grupo de Investigación en Acuicultura, ULPGC & ICCM, Aptdo. de Correos 56, Las Palmas, Telde, Spain. enekoganuza@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Ganuza
authors.forename: A J
authors.initials: AJ
authors.lastname: Anderson
authors.forename: C
authors.initials: C
authors.lastname: Ratledge
mesh_terms: D019149:Bioreactors; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D056890:Eukaryota / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development; D005227:Fatty Acids / Q000032:analysis; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*
chemical_list: D005227:Fatty Acids; D000644:Quaternary Ammonium Compounds; D005947:Glucose