title: Polyhydroxyalkanoates accumulation by Methylobacterium organophilum CZ-2 during methane degradation using citrate or propionate as cosubstrates.
abstract: Methylobacterium organophilum CZ-2 synthesized polyhydroxyalkanoates (PHAs) under nitrogen limitation with CH4 as carbon source and when either citrate or propionate was added as cosubstrates. The highest PHAs content (yPHA) in closed flasks was obtained in the CH4-citrate and CH4-propionate experiments attaining values of 0.82 and 0.68, respectively. M. organophilum CZ-2 cultivated in bioreactors with citrate and continuous CH4 addition yielded a final PHAs concentration of 143 gm(-3) containing hydroxybutyrate (HB), hydroxyvalerate (HV) and hydroxyoctanoate (HO), in a 55:35:10 ratio, with, yPHA of 0.88 and a CH4 elimination capacity (EC) of 20 gm(-3) h(-1). With propionate, the yPHA was 0.3 and the EC around 8 gm(-3) h(-1). From 1H and 13C NMR experiments it was found that the polymer produced with CH4-citrate contained six different monomers: 3HB, 3HV, 4HV, 4-hydroxyheptanoate (4HH), 3HO and 4HO, showing the great versatility of this PHAs producing bacterium.
authors.affiliation: Posgrado de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Mexico.
authors.forename: Cristal
authors.initials: C
authors.lastname: Zuñiga
authors.forename: Marcia
authors.initials: M
authors.lastname: Morales
authors.forename: Sergio
authors.initials: S
authors.lastname: Revah
mesh_terms: D019343:Citric Acid / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D020580:Methylobacterium / Q000145:classification / Q000378:metabolism*; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis* / Q000302:isolation & purification*; D011422:Propionates / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D054813:Polyhydroxyalkanoates; D011422:Propionates; D019343:Citric Acid; D008697:Methane