Izvorni znanstveni članak
https://doi.org/10.15255/CABEQ.2015.2276
Agitation Effects and Kinetic Constants of Exoglucomannan Production by Antarctic Yeast Strain in a Stirred Tank Bioreactor
S. D. Vlaev
; Institute of Chemical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Bl.103, 1113 Sofia, Bulgaria
K. Pavlova
; Institute of Microbiology Lab of Applied Biotechnologies, Bulgarian Academy of Sciences, 139 Ruski Blvd, 4000, Plovdiv, Bulgaria
S. Rusinova-Videva
; Institute of Microbiology Lab of Applied Biotechnologies, Bulgarian Academy of Sciences, 139 Ruski Blvd, 4000, Plovdiv, Bulgaria
K. Georgieva
; Institute of Microbiology Lab of Applied Biotechnologies, Bulgarian Academy of Sciences, 139 Ruski Blvd, 4000, Plovdiv, Bulgaria
D. Georgiev
; Bourgas University “Prof. Dr. A. Zlatarov” Chemical Engineering Department, 1, Blvd. Prof. Yakimov, 8010 Bourgas, Bulgaria
Sažetak
Exoglucomannan production by Antarctic yeast Sporobolomyces salmonicolor AL1 is studied at semi-tech scale in a 5 L stirred tank bioreactor and the bioreaction kinetics is quantified. The organism’s unconventional response to agitation is analyzed in terms of the agitation-induced mechanical stress. The yeast maximum production activity was observed at agitation rate 400 rpm and conserved or decreased at further increase in mixing intensity. Referring to the relationship of cell growth and aeration intensity, the various production activity, oxygen availability and cell growth are considered as a starting point to elucidate the possible reasons for the anomaly. At suspicion of shear detrimental effect on the yeast cells, the hydrodynamic stress acting on cell particles is determined and the microorganism morphology at low and high mixing intensity is examined. Biological stability is registered and the agitation effect is attributed to depressed metabolic activity at the evolving dissolved oxygen tension rather than to direct effect of hydrodynamics. A kinetic model is proposed. The specific growth rate (µ, h–1) and growth-associated (g EPS g–1 cells), and non-growth associated (g EPS g–1 cells h–1) production constants are determined and compared with reported estimates for similar reference EPS
fermentations. The model and its parameters are determined in well-mixed cultures and could be upgraded further to account for mixing non-ideality and mass transfer in larger vessels.
Ključne riječi
exoglucomannan; Sporobolomyces salmonicolor Al1; hydrodynamic stress; morphology; kinetic modeling
Hrčak ID:
172285
URI
Datum izdavanja:
6.1.2017.
Posjeta: 1.371 *