title: High cell-density production of poly(3-hydroxybutyrate) in a membrane bioreactor.
abstract: Agro-industrial residues with a low carbon content, such as whey, stillage or wastewater from plant oil mills are abundant and cheap. However, they cannot be used directly in highly productive industrial poly(3-hydroxybutyrate) (P3HB) production, as the classical fed-batch fermentation strategy requires highly concentrated feed streams. This problem has been circumvented in this report by retaining the cells during the fermentation in the bioreactor using an external microfiltration module. Synthetic medium containing a glucose concentration of 50g/L was continuously fed to Cupriavidus necator, which converted the sugar to P3HB. With this setup we were able to achieve high productivities (3.10g P3HB/(Lh)) and reach high cell densities (148g/L) containing 76% P3HB, and obtained good yields (0.33g P3HB/g added glucose). The added sugar from the feed was instantly consumed by the bacteria, resulting in a negligible loss of sugar to the permeate. This approach creates the possibility of polyhydroxyalkanoate production from a range of cheap and easily available substrates, for which only waste water treatment or biogas production has been cost-competitive until now.
authors.affiliation: Institute of Environmental Biotechnology, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Haas
authors.affiliation: Institute of Environmental Biotechnology, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
authors.forename: Tarek
authors.initials: T
authors.lastname: El-Najjar
authors.affiliation: Institute of Environmental Biotechnology, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Virgolini
authors.affiliation: Institute of Environmental Biotechnology, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
authors.forename: Marina
authors.initials: M
authors.lastname: Smerilli
authors.affiliation: Institute of Environmental Biotechnology, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria. Electronic address: markus.neureiter@boku.ac.at.
authors.forename: Markus
authors.initials: M
authors.lastname: Neureiter
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology; D020118:Cupriavidus necator / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D005947:Glucose; D006885:Hydroxybutyrates; D009584:Nitrogen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Cell recycle fed-batch; Cupriavidus necator; High productivity; Low carbon substrate; Polyhydroxyalkanoate production; Waste material