title: Influence of the cycle length on the production of PHA and polyglucose from glycerol by bacterial enrichments in sequencing batch reactors.
abstract: PHA, a naturally occurring biopolymer produced by a wide range of microorganisms, is known for its applications as bioplastic. In recent years the use of agro-industrial wastewater as substrate for PHA production by bacterial enrichments has attracted considerable research attention. Crude glycerol as generated during biodiesel production is a waste stream that due to its high organic matter content and low price could be an interesting substrate for PHA production. Previously we have demonstrated that when glycerol is used as substrate in a feast-famine regime, PHA and polyglucose are simultaneously produced as storage polymers. The work described in this paper aimed at understanding the effect of the cycle length on the bacterial enrichment process with emphasis on the distribution of glycerol towards PHA and polyglucose. Two sequencing batch reactors where operated with the same hydraulic and biomass retention time. A short cycle length (6 h) favored polyglucose production over PHA, whereas at long cycle length (24 h) PHA was more favored. In both communities the same microorganism appeared dominating, suggesting a metabolic rather than a microbial competition response. Moreover, the presence of ammonium during polymer accumulation did not influence the maximum amount of PHA that was attained.
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC, Delft, The Netherlands; Department of Chemical Engineering, University of Santiago de Compostela, Lope Gomez de Marzoa s/n, 15705, Santiago de Compostela, Spain.
authors.forename: Helena
authors.initials: H
authors.lastname: Moralejo-Gárate
authors.forename: Tania
authors.initials: T
authors.lastname: Palmeiro-Sánchez
authors.forename: Robbert
authors.initials: R
authors.lastname: Kleerebezem
authors.forename: Anuska
authors.initials: A
authors.lastname: Mosquera-Corral
authors.forename: José Luis
authors.initials: JL
authors.lastname: Campos
authors.forename: Mark C M
authors.initials: MC
authors.lastname: van Loosdrecht
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology; D058448:Biota; D003470:Culture Media / Q000737:chemistry; D005936:Glucans / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D013997:Time Factors
chemical_list: D064751:Ammonium Compounds; D003470:Culture Media; D005936:Glucans; D054813:Polyhydroxyalkanoates; D005990:Glycerol
keywords: F/M ratio; PHB; bioplastic; feast-famine; glycerol; polyglucose