title: Enhanced rhamnolipids production by Pseudomonas aeruginosa based on a pH stage-controlled fed-batch fermentation process.
abstract: Rhamnolipids find broad applications as natural surfactants, emulsifiers, and antibiotics because of their low toxicity, high biodegradability and environmental soundness. In this study, a pH stage-controlled process of fermentation of rhamnolipids by Pseudomonas aeruginosa O-2-2 was established. A yield of 24.06 g/L in batch fermentation was achieved in a 5-L fermentor via the optimization of stirring speed. By controlling pH, rhamnolipid production was increased to 28.8 g/L, an improvement of 19.7%, and more substrate was converted to rhamnolipids rather than to biomass. Fermentation kinetics models for cell growth, product synthesis and substrate consumption based on the pH stage-controlled fermentation indicated that rhamnolipid production could be further improved by fed-batch fermentation. Rhamnolipid production reached 70.56 g/L, an improvement of 193%, in the pH stage-controlled fed-batch fermentation when the stirring speeds was controlled at 500 rpm and the fermentation temperature was maintained at 30 °C.
authors.affiliation: Department of Biological Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Lingqing
authors.initials: L
authors.lastname: Zhu
authors.forename: Xue
authors.initials: X
authors.lastname: Yang
authors.forename: Chaoyou
authors.initials: C
authors.lastname: Xue
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: Liang
authors.initials: L
authors.lastname: Qu
authors.forename: Wenyu
authors.initials: W
authors.lastname: Lu
mesh_terms: D061249:Batch Cell Culture Techniques / Q000379:methods*; D018533:Biomass; D005285:Fermentation / Q000502:physiology*; D006017:Glycolipids / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism*; D012995:Solubility
chemical_list: D006017:Glycolipids; C418382:rhamnolipid; D010100:Oxygen