Effect of dark/light periods on the polyhydroxyalkanoate production of a photosynthetic mixed culture.
This work studied the possibility of operating a viable polyhydroxyalkanoate (PHA) producing photosynthetic mixed culture (PMC) under dark/light periods without aeration. The culture was subjected to a feast and famine regime, being fed in the dark phase and entering into famine during the light phase. Throughout consecutive feast and famine dark/light periods, the PMC became enriched in PHA accumulating organisms, where non-PHA producing algae that can grow under continuous illumination were out-competed. The very low algae levels enabled greater light and carbon source availability for PHA accumulating bacteria, leading to higher metabolic rates and PHA levels. The PMC reached a PHA content of 30% PHA/VSS, and doubled its specific PHA production rate in relation to PMCs operated previously under continuous illumination. This new process takes a further step towards operating a more cost effective PMC system for PHA production, opening up the possibility for direct sunlight utilization in the future.
REQUIMTE/CQFB, Chemistry Dpt., FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
J C
JC
Fradinho
A
A
Oehmen
M A M
MA
Reis
D000222:Adaptation, Physiological; D001419:Bacteria / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D018533:Biomass; D018929:Cell Culture Techniques / Q000379:methods*; D003624:Darkness; D006885:Hydroxybutyrates / Q000378:metabolism; D007700:Kinetics; D017440:Photoperiod; D010788:Photosynthesis; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D014835:Volatilization
D006885:Hydroxybutyrates; D054813:Polyhydroxyalkanoates
Anaerobic culture selection; Dark/light cycles; Feast and famine; Photosynthetic mixed cultures; Polyhydroxyalkanoates (PHA)