Synthesis of polyhydroxyalkanoates in municipal wastewater treatment.
Biologically derived polyesters known as polyhydroxyalkanoates (PHAs) represent a potentially "sustainable" replacement to fossil-fuel-based thermoplastics. However, current commercial practices that produce PHA with pure microbial cultures grown on renewable, but refined, feedstocks (i.e., glucose) under sterile conditions do not represent a sustainable commodity. Here, we report on PHA production with a mixed microbial consortium indigenous to an activated sludge process on carbon present in municipal wastewaters. Reactors operated under anaerobic/aerobic and aerobic-only mode and fed primary solids fermenter liquor maintained a mixed microbial consortium capable of synthesizing PHA at 10 to 25% (w/w), while reducing soluble COD by approximately 62 to 71%. More critically, an aerobic batch reactor seeded from the anaerobic/aerobic reactor and fed fermenter liquor achieved approximately 53% PHA (w/w). Results presented suggest that environmentally benign production of biodegradable polymers is feasible. We further used PHA-rich biomass to produce a natural fiber-reinforced thermoplastic composite that can be used to offset advanced wastewater treatment costs.
Department of Civil Engineering, University of Idaho, Moscow, Idaho, USA.
Erik R
ER
Coats
Frank J
FJ
Loge
Michael P
MP
Wolcott
Karl
K
Englund
Armando G
AG
McDonald
D001420:Bacteria, Aerobic / Q000254:growth & development / Q000378:metabolism; D001421:Bacteria, Anaerobic / Q000254:growth & development / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D011091:Polyesters / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*
D011091:Polyesters; D054813:Polyhydroxyalkanoates; D012722:Sewage