Bioconversion from crude glycerin by Xanthomonas campestris 2103: xanthan production and characterization

• Main Authors: L. V. Brandão, D. J. Assis, J. A. López, M. C. A. Espiridião, E. M. Echevarria, J. I. Druzian
• Format: Article
• Language: English
• Published: Brazilian Society of Chemical Engineering 2013-12-01
• Series: Brazilian Journal of Chemical Engineering
• Subjects: Xanthan; Biodiesel waste; Xanthomonas isolate from Brazil; Drilling fluid
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66322013000400006&lng=en&tlng=en

The production and rheological properties of xanthan gum from crude glycerin fermentation, a primary by-product of the biodiesel industry with environmental and health risks, were evaluated. Batch fermentations (28 °C/250 rpm /120 h) were carried out using crude glycerin, 0.01% urea and 0.1% KH2PO4, (% w/v), and compared to a sucrose control under the same operational conditions, using Xanthomonas campestris strain 2103 isolate from Brazil. Its maximal production by crude glycerin fermentation was 7.23±0.1 g·L-1 at 120 h, with an apparent viscosity of 642.57 mPa·s, (2 % w/v, 25 °C, 25 s-1), 70% and 30% higher than from sucrose fermentation, respectively. Its molecular weight varied from 28.2 to 36.2×10(6) Da. The Ostwald-de-Waele model parameters (K and n) indicated a pseudoplastic behavior at all concentrations (0.5 to 2.0 %, w/v) and temperatures (25-85 °C), while its consistency index indicated promising rheological properties for drilling fluid applications. Therefore, crude glycerin has potential as a cost-effective and alternative substrate for non-food grade xanthan production.