Rhodospirillum rubrum: utilization of condensed corn solubles for poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) production.
OBJECTIVE
This study sought to develop a less expensive medium for growth of the polyhydroxyalkanoate-producing bacterium Rhodospirillum rubrum from the ethanol production coproduct, condensed corn solubles (CCS).


RESULTS
Small-scale trials using R. rubrum were performed in aerated or anaerobic stoppered serum bottles filled with media. The CCS (240 g l(-1)) achieved a maximum cell density and growth rate comparable with the defined supplemented malate-ammonium medium (mSMN) or tryptic soy broth. Microaerophilic solubles medium cultures exhibited significantly higher maximum cell densities and growth rates than did strictly anaerobic cultures; while illumination, nickel or biotin addition had no effect. Growth of R. rubrum in a pH controlled bioreactor was significantly better in CCS (240 g l(-1)) than in mSMN medium and supported production of 0.36% (cell dry weight) poly-(3-hydroxybutyrate-Co-3-hydroxyvalerate) after 24 h.


CONCLUSIONS
A CCS medium was devised that supported R. rubrum growth for biopolymer production as effective as the defined medium.


CONCLUSIONS
This study demonstrates that a more economical medium can be developed for biopolymer production using a low value coproduct from ethanol production. The impact is that this inexpensive solubles medium may make it more economical to produce the biopolymer on a commercial scale.
Smith
R L
RL
Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA. beccaleigh@hotmail.com
West
T P
TP
Gibbons
W R
WR
D019149:Bioreactors / Q000382:microbiology*; D003470:Culture Media; D007218:Industrial Microbiology; D008027:Light; D010100:Oxygen / Q000378:metabolism; D011091:Polyesters / Q000032:analysis / Q000378:metabolism*; D012247:Rhodospirillum rubrum / Q000254:growth & development / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
D003470:Culture Media; D010100:Oxygen; D011091:Polyesters; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates