DBPapers
DOI: 10.5593/SGEM2014/B61/S25.041

CHALLANGING THE BIOGEOCHEMICAL POTENTIAL OF ANTARCTIC YEAST: BIOREACTOR DYNAMICS IN VISCOUS BROTHS CONTAINING EXOPOLYSACCHARIDES

S. Vlaev, M. Martinov, K. Pavlova, S. Rusionova-Videva, D. Georgiev
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-20-9 / ISSN 1314-2704, June 19-25, 2014, Book 6, Vol. 1, 293-300 pp

ABSTRACT
The biogeochemical potentials of cold-tolerant Antarctic microorganisms to release organic matter has allowed production of valuable components of pharmaceuticals and food. Recently, a bioprocess for exopolysaccharides and biomass involving Antarctic yeast has been introduced and put forward for examination. The fermentation broth is viscous and non-Newtonian and good mixing and oxygen transfer are essential for the microorganisms. The paper presents a study of the bioreactor performance that evolves when using a modified backswept impeller termed impeller MV. As related to the importance of oxygen for the specific yeast metabolism and based on preliminary data, the bioreactor dynamics is studied both experimentally and by simulation. The impeller power draw gas volume fraction and oxygen mass transfer were measured and the bioreactor fluid dynamics corresponding to the bioprocess evolution were evealed. New experimental data is obtained. The results are compared with reference data for the conventional bioreactor equipped with two six flat-blade turbines. Both reactive and non-reactive conditions related to the bioreaction evolution are studied. Moderate rotational speeds typical for the conventional impeller were applied and the bioprocess time-course for the two mixing cases was registered. The bioprocess corresponding to MV mixing has been found to be slightly delayed what is discussed in terms of the impeller specific substrate distribution and its weaker gas dispersion function. Good gassed power draw and drag reduction properties of the impeller are found that allow its application at high rotational speed and further multiple impeller configurations.

Keywords: bioreactor, exopolysaccharides (EPS), Antarctic yeast, impeller mixing