title: Polyhydroxybutyrate production from lactate using a mixed microbial culture.
abstract: In this study we investigated the use of lactate and a lactate/acetate mixture for enrichment of poly-3-hydroxybutyrate (PHB) producing mixed cultures. The mixed cultures were enriched in sequencing batch reactors (SBR) that established a feast-famine regime. The SBRs were operated under conditions that were previously shown to enable enrichment of a superior PHB producing strain on acetate (i.e., 12 h cycle length, 1 day SRT and 30°C). Two new mixed cultures were eventually enriched from activated sludge. The mixed culture enriched on lactate was dominated by a novel gammaproteobacterium. This enrichment can accumulate over 90 wt% PHB within 6 h, which is currently the best result reported for a bacterial culture in terms of the final PHB content and the biomass specific PHB production rate. The second mixed culture enriched on a mixture of acetate and lactate can produce up to 84 wt% PHB in just over 8 h. The predominant bacterial species in this culture were Plasticicumulans acidivorans and Thauera selenatis, which have both been reported to accumulate large amounts of PHB. The data suggest that P. acidivorans is a specialist on acetate conversion, whereas Thauera sp. is a specialist on lactate conversion. The main conclusion of this work is that the use of different substrates has a direct impact on microbial composition, but has no significant effect on the functionality of PHB production process.
authors: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors: Yang
authors: Y
authors: Jiang
authors: Leonie
authors: L
authors: Marang
authors: Robbert
authors: R
authors: Kleerebezem
authors: Gerard
authors: G
authors: Muyzer
authors: Mark C M
authors: MC
authors: van Loosdrecht
mesh_terms: D000085:Acetates / Q000032:analysis / Q000378:metabolism; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D018920:Coculture Techniques; D020563:Gammaproteobacteria / Q000235:genetics / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D019344:Lactic Acid / Q000032:analysis / Q000378:metabolism*; D056265:Microbial Interactions; D008954:Models, Biological; D010802:Phylogeny; D011091:Polyesters / Q000032:analysis / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D000085:Acetates; D006885:Hydroxybutyrates; D019344:Lactic Acid; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates