title: Effect of process parameters on production of a biopolymer by Rhizobium sp.
abstract: The production of biopolymers by a Rhizobium strain was studied under batch and bioreactor conditions. The best viscosity levels were obtained under low mannitol concentrations as well as low agitation and aeration conditions. Infrared spectra indicated the presence of chemical groups characteristic of microbially produced biopolymers, including C = O and O-acetyl groups. Thermogravimetric analysis showed the characteristic degradation profiles of the exopolysaccharide produced (T(onset) = 290degreesC). The experimental design showed that a low substrate concentration (10.0 g/L), and low aeration (0.2 vvm) and agitation (200 rpm) levels should be used. The maximum yield of the process was a Yp/s (g/g) of 0.19 +/- 0.1, obtained under optimized conditions.
authors.affiliation: Universidade Federal do Rio de Janeiro, Departamento de Engenharia Bioquímica, Bloco E, Ilha do Fundão, Rio de Janeiro, RJ CEP: 21949-900 Brazil.
authors.forename: Flávia Pereira
authors.initials: FP
authors.lastname: Duta
authors.forename: Francisca Pessôa
authors.initials: FP
authors.lastname: De França
authors.forename: Eliana Flávia Camporese
authors.initials: EF
authors.lastname: Sérvulo
authors.forename: Léa Maria
authors.initials: LM
authors.lastname: De Almeida Lopes
authors.forename: Antonio Carlos Augusto
authors.initials: AC
authors.lastname: Da Costa
authors.forename: Ana
authors.initials: A
authors.lastname: Barros
mesh_terms: D000362:Agar / Q000737:chemistry; D018533:Biomass; D001704:Biopolymers / Q000737:chemistry*; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008353:Mannitol / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D012231:Rhizobium / Q000378:metabolism*; D013055:Spectrophotometry, Infrared; D013223:Statistics as Topic; D013696:Temperature; D014783:Viscosity
chemical_list: D001704:Biopolymers; D003470:Culture Media; D011134:Polysaccharides; D008353:Mannitol; D000362:Agar