title: Optimizing conditions for poly(beta-hydroxybutyrate) production by Halomonas boliviensis LC1 in batch culture with sucrose as carbon source.
abstract: Halomonas boliviensis LC1 is able to accumulate poly(beta-hydroxybutyrate) (PHB) under conditions of excess carbon source and depletion of essential nutrients. This study was aimed at an efficient production of PHB by growing H. boliviensis to high cell concentrations in batch cultures. The effect of ammonium, phosphate, and yeast extract concentrations on cell concentration [cell dry weight (CDW)] and PHB content of H. boliviensis cultured in shake flasks was assayed using a factorial design. High concentrations of these nutrients led to increments in cell growth but reduced the PHB content to some extent. Cultivations of H. boliviensis under controlled conditions in a fermentor using 1.5% (w/v) yeast extract as N source, and intermittent addition of sucrose to provide excess C source, resulted in a polymer accumulation of 44 wt.% and 12 g l(-1) CDW after 24 h of cultivation. Batch cultures in a fermentor with initial concentrations of 2.5% (w/v) sucrose and 1.5% (w/v) yeast extract, and with induced oxygen limitation, resulted in an optimum PHB accumulation, PHB concentration and CDW of 54 wt.%, 7.7 g l(-1) and 14 g l(-1), respectively, after 19 h of cultivation. The addition of casaminoacids in the medium increased the CDW to 14.4 g l(-1) in 17 h but reduced the PHB content in the cells to 52 wt.%.
authors.affiliation: Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, 221 00 Lund, Sweden. Jorge.Quillaguaman@biotek.lu.se
authors.forename: Jorge
authors.initials: J
authors.lastname: Quillaguamán
authors.forename: Marlene
authors.initials: M
authors.lastname: Muñoz
authors.forename: Bo
authors.initials: B
authors.lastname: Mattiasson
authors.forename: Rajni
authors.initials: R
authors.lastname: Hatti-Kaul
mesh_terms: D046508:Culture Techniques / Q000379:methods; D020632:Halomonas / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D007218:Industrial Microbiology; D011091:Polyesters / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D006885:Hydroxybutyrates; D011091:Polyesters; D013395:Sucrose; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates