title: Enrichment of a mixed bacterial culture with a high polyhydroxyalkanoate storage capacity.
abstract: Polyhydroxyalkanoates (PHAs) are microbial storage polymers that attract interest as bioplastics. PHAs can be produced with open mixed cultures if a suitable enrichment step based on the ecological role of PHA is used. An acetate-fed sequencing batch reactor operated with 1 day biomass residence time and with feast-famine cycles of 12 h was used to enrich a mixed culture of PHA producers. In subsequent fed-batch experiments under growth limiting conditions, the enriched mixed culture produced PHA up to a cellular content of 89 wt % within 7.6 h (average rate of 1.2 g/g/h). The PHA produced from acetate was the homopolymer polyhydroxybutyrate. The culture was dominated by a Gammaproteobacterium that showed little similarity on 16S rRNA level with known bacteria (<90% sequence similarity). The mixed culture process for PHA production does not require aseptic conditions. Waste streams rather than pure substrates could be used as raw materials.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: Katja
authors.initials: K
authors.lastname: Johnson
authors.forename: Yang
authors.initials: Y
authors.lastname: Jiang
authors.forename: Robbert
authors.initials: R
authors.lastname: Kleerebezem
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
authors.forename: Mark C M
authors.initials: MC
authors.lastname: van Loosdrecht
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D001420:Bacteria, Aerobic / Q000254:growth & development / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D004275:DNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D010802:Phylogeny; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism
chemical_list: D004275:DNA, Ribosomal; D054813:Polyhydroxyalkanoates; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D019342:Acetic Acid