title: A Burkholderia sacchari cell factory: production of poly-3-hydroxybutyrate, xylitol and xylonic acid from xylose-rich sugar mixtures.
abstract: Efficient production of poly-3-hydroxybutyrate (P(3HB)) based on glucose-xylose mixtures simulating different types of lignocellulosic hydrolysate (LCH) was addressed using Burkholderia sacchari, a wild strain capable of metabolizing both sugars and producing P(3HB). Carbon catabolite repression was avoided by maintaining glucose concentration below 10g/L. Xylose concentrations above 30g/L were inhibitory for growth and production. In fed-batch cultivations, pulse size and feed addition rate were controlled in order to reach high productivities and efficient sugar consumptions. High xylose uptake and P(3HB) productivity were attained with glucose-rich mixtures (glucose/xylose ratio in the feed=1.5w/w) using high feeding rates, while with xylose-richer feeds (glucose/xylose=0.8w/w), a lower feeding rate is a robust strategy to avoid xylose build-up in the medium. Xylitol production was observed with xylose concentrations in the medium above 30-40g/L. With sugar mixtures featuring even lower glucose/xylose ratios, i.e. xylose-richer feeds (glucose/xylose=0.5), xylonic acid (a second byproduct) was produced. This is the first report of the ability of Burkholderia sacchari to produce both xylitol and xylonic acid.
authors.affiliation: IBB-Institute for Bioengineering and Biosciences, Bioengineering Department, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: Rodrigo S
authors.initials: RS
authors.lastname: Raposo
authors.affiliation: IBB-Institute for Bioengineering and Biosciences, Bioengineering Department, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; CIIEM-Centro de Investigação Interdisciplinar Egas Moniz, ISCSEM, Campus Universitário, Quinta da Granja, 2829-511 Monte de Caparica, Portugal.
authors.forename: M Catarina M D
authors.initials: MC
authors.lastname: de Almeida
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: M da Conceição M A
authors.initials: MD
authors.lastname: de Oliveira
authors.affiliation: IBB-Institute for Bioengineering and Biosciences, Bioengineering Department, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: M Manuela
authors.initials: MM
authors.lastname: da Fonseca
authors.affiliation: IBB-Institute for Bioengineering and Biosciences, Bioengineering Department, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Electronic address: teresa.cesario@tecnico.ulisboa.pt.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Cesário
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology; D019117:Burkholderia / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D013400:Sugar Acids / Q000378:metabolism; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D005947:Glucose; D006885:Hydroxybutyrates; D008031:Lignin; D011091:Polyesters; D013400:Sugar Acids; D014993:Xylitol; D014994:Xylose; C036909:lignocellulose; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Burkholderia sacchari; Glucose/xylose mixtures; Poly-3-hydroxybutyrate; Xylitol; Xylonic acid; Xylose consumption