title: A study of the effects of aeration and agitation on the properties and production of xanthan gum from crude glycerin derived from biodiesel using the response surface methodology.
abstract: The effects of aeration and agitation on the properties and production of xanthan gum from crude glycerin biodiesel (CGB) by Xanthomonas campestris mangiferaeindicae 2103 were investigated and optimized using a response surface methodology. The xanthan gum was produced from CGB in a bioreactor at 28 °C for 120 h. Optimization procedures indicated that 0.97 vvm at 497.76 rpm resulted in a xanthan gum production of 5.59 g L(-1) and 1.05 vvm at 484.75 rpm maximized the biomass to 3.26 g L(-1). Moreover, the combination of 1.05 vvm at 499.40 rpm maximized the viscosity of xanthan at 0.5% (m/v), 25 °C, and 25 s(-1) (255.40 mPa s). The other responses did not generate predictive models. Low agitation contributed to the increase of xanthan gum production, biomass, viscosity, molecular mass, and the pyruvic acid concentration. Increases in the agitation contributed to the formation of xanthan gum with high mannose concentration. Decreases in the aeration contributed to the xanthan gum production and the formation of biopolymer with high mannose and glucose concentrations. Increases in aeration contributed to increased biomass, viscosity, and formation of xanthan gum with greater resistance to thermal degradation. Overall, aeration and agitation of CGB fermentation significantly influenced the production of xanthan gum and its properties.
authors.affiliation: Department of Chemical Engineering, Polytechnic School, Federal University of Bahia, Aristides Novis Street, n° 2, Second Floor, Federação, Salvador, Bahia, 40210-630, Brazil, denilsonengal@gmail.com.
authors.forename: Denilson
authors.initials: D
authors.lastname: de Jesus Assis
authors.forename: Líllian Vasconcelos
authors.initials: LV
authors.lastname: Brandão
authors.forename: Larissa Alves
authors.initials: LA
authors.lastname: de Sousa Costa
authors.forename: Tamiris Vilas Boas
authors.initials: TV
authors.lastname: Figueiredo
authors.forename: Luciane Santos
authors.initials: LS
authors.lastname: Sousa
authors.forename: Francine Ferreira
authors.initials: FF
authors.lastname: Padilha
authors.forename: Janice Izabel
authors.initials: JI
authors.lastname: Druzian
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D005163:Factor Analysis, Statistical; D005285:Fermentation; D005947:Glucose / Q000032:analysis; D005990:Glycerol / Q000378:metabolism*; D008358:Mannose / Q000032:analysis; D010100:Oxygen / Q000378:metabolism* / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry; D019289:Pyruvic Acid / Q000378:metabolism; D012399:Rotation; D014783:Viscosity; D016959:Xanthomonas campestris / Q000187:drug effects / Q000378:metabolism*
chemical_list: D056804:Biofuels; D011135:Polysaccharides, Bacterial; D019289:Pyruvic Acid; D005947:Glucose; D005990:Glycerol; D008358:Mannose; D010100:Oxygen; C002563:xanthan gum