Main Article Content

Serafim Dimitrov Vlaev Iren Tsibranska Daniela Dzhonova-Atanasova Roman Popov


Separation of value-added food additives is often practiced by micro and ultrafiltration membranes in integrated submerged membrane bioreactors (sMBR) and the flow conditions are of major importance for their performance. The immersed membranes affect fluid circulation and may cause operational difficulties. Such malfunction termed flow structural deterioration of integrated vessels is addressed in this study, based on the effect of the (1) non-Newtonian component presence, and the (2) gas flow rate. Ranges of input parameters referring to power law non-Newtonian fluids with consistency coefficients of 0.02 to (flow index n<1) and gas flow rate 1 - 2vvm are studied. Computational fluid dynamics (CFD) simulation of a dual impeller bioreactor equipped with a mono-tubular membrane module and alternatively flat-blade or curved-blade impellers was carried out. 3-D    “k-ε” turbulent flow model is used and 2-D contour plots are worked out to illustrate cases of restricted fluid mobility in the vicinity of membrane walls. The corresponding performance parameters, gas volume fraction and fluid surface velocity are discussed. Flow structural anomalies referring to zones at the immersed membranes of extremely low membrane surface velocity (<1mm.s-1) and velocity gradients (<10s-1) that are risky for membrane fouling are uncovered.
Practical applications. Fermentation of food ingredients in stirred vessels combined with recovery of the value-added product is the target application. Examples are the production and recovery of peptides, gums’ (gelatin, pectin) concentration, production of fructoolligosaccharides, galactoglucomannan, enzymatic hydrolysis combined with selective ultrafiltration in processing of vegetable proteins, production of antioxidants. Viscous dispersions of food ingredients such as starch or xanthan and operating variables - impeller speed, rate of gassing - at various level may cause undesirable effects in the bioreactor flow uniformity leading to decrease of membrane separation efficiency. The cases engaging process fluids of high consistency such as exopolysaccharide dispersions are specific in this category. Restricted fluid mobility in the vicinity of the membrane module reduces the rate of fusion across the membrane surface and blocks up the product recovery. The resulting membrane fouling and the flow structural anomalies adhere to the problem of fouling control and to submerged membrane bioreactor applications

Article Details


Bohm, L., Drews A., Prieske H., Berube P. R., Kraume M. The importance of fluid dynamics for MBR fouling mitigation. Bioresource Technology, 2012, 122(10): 50-61.

Buwa, V. V., Roy Sh., Ranade V. V. Three-phase slurry reactors. Chapter 6. In: Multiphase Catalytic Reactors: Theory, Design, Manufacturing and Applications (Z. I. Onsan, A. K. Avci, Eds.). Wiley, New Jersey. 2016, рр. 132-156, Print ISBN: 9781118115763, Online ISBN: 9781119248491,

Camelini, M., Rezzadori K., Benedetti S., Proner M. C., Fogaça L., Azambuja A. A., Giachini A. J., Rossi M. J., Petrus J. C. C. Nanofiltration of polysaccharides from Agaricus subrufescens. Applied Microbiology and Biotechnology, 2013, 97(23): 9993-10002.

Chakraborty, S., Drioli E., Giorno L. Development of a two separate phase submerged biocatalytic membrane reactor for the production of fatty acids and glycerol from residual vegetable oil streams. Biomass and Bioenergy, 2012, 46(11): 574-558.

Dalmau, M., Monclús H., Gabarrón S., Rodriguez-Roda I., Comas J. Towards integrated operation of membrane bioreactors: Effects of aeration on biological and filtration performance. Bioresource Technology, 2014, 171(11): 103-112.

Daufin, D., Escudier J.-P., Carre H., Re Á., Bearot S., Fillaudeau L., Decloux M. Recent and emerging applications of membrane processes in the food and dairy industry. Food and Bioproducts Processing, 2001, 79(2): 89-102.

Demirci, A. S., Palabıyık I., Deniz A. D., Apaydin D., Gümüs T. Yield and rheological properties of exopolysaccharide from a local isolate: Xanthomonas axonopodis. Electronic Journal of Biotechnology, 2017, 29(11): 18-23.

Dhariwal, A. The significance of submerged ceramic membrane systems for production oriented bioprocesses. PhD Thesis, Fakultät 8-Naturwissenschaftlich-Technische Fakultät III, University of Saarland, 2007 [in German]

Fane, A.G. Submerged membranes. Chapter 10. In: Advanced Membrane Technology and Applications (N.N. Li, A.G. Fane, W.S. Winston-Ho, T. Matsuura, Eds.). Wiley, New Jersey. 2008, рр. 239-270, Print ISBN: 9780471731672, Online ISBN: 9780470276280,

Giorno L., Mazzei R., Piacentini E., Drioli E. Food application of membranes. Chapter 9 In: Engineering Aspects of Membrane Separation and Application in Food Processing (R. Field, E. Bekassy-Molnar, F. Lipnizki, G. Vatai Eds.). Taylor & Francis Group CRC Press, Boca Raton, Florida. 2017, рр. 299-360, Print ISBN-10: 1420083635, Online ISBN-13: 978-1420083637

Coutte F., Leciuturier D., Firdaous L., Kapel R., Bazinet L., Cabassud C., Dhulster P. Recent Trends in Membrane Bioreactors. Chapter 10 In: Current Developments in Biotechnology and Bioengineering. Bioprocesses, Bioreactors and Controls. (Ch. Larroche, M. A. Sanroman, G. Du, A. Pandey Eds.). Elsevier Ltd., Amsterdam. 2017, рр. 279-303, ISBN: 978-0-444-63663-8.

Lipnizki, F. Cross-flow membrane applications in the food industry. Chapter 1 In: Membrane technology. Volume 3: Membranes for food applications (K-V. Peinemann, S. P. Nunes, L. Giorno Eds.). Wiley-VCH Verlag, Weinheim. 2010 pp. 1-2. ISBN: 978-3-527-31482-9.

Pavlova K, Rusinova-Videva S., Kuncheva M., Kratchanova M., Gocheva M., Dimitrova S. Synthesis and characterization of an exopolysaccharide by Antarctic yeast strain Cryptococcus laurentii AL100. Applied Biochemistry and Biotechnology, 2011, 163(8): 1038-1052.

Persson, T., Jönsson A. S. Isolation of hemi-celluloses by ultrafiltration of thermomechanical pulp mill process water. Influence of operating conditions. Chemical Engineering Research and Design, 2010, 88(12): 1548-1554.

Sanchez, O., Guio F., Garcia D., Silva E., Caicedo L. Fructooligosaccharides production by Aspergillus sp. N74 in a mechanically agitated airlift reactor. Food and Bioproducts Processing, 2008, 86(2): 109-115.

Vlaev, S. D., Dzhonova-Atanasova D. Local velocity and shear deformation rate at model membranes immersed in a bioreactor agitated by curved blade impeller: The effect of membrane position. Materials, Methods & Technologies - Journal of International Scientific Publications, 2017, 11(1): 216-229.

Vlaev, S. D., Georgiev D. CFD-characteriza-tion of the MV-impeller related to polysaccharide dispersion mixing, Scientific Works of University of Food Technologies, 2014, 61(1): 745-749.

Vlaev, S. D., Martinov M., Georgiev D. RANS-modeling of macroparameter distribution in dual impeller stirred bioreactors for ESP production. Scientific Works of University of Food Technologies, 2012, 53(1): 840-845 [in Bulgarian]

Vlaev S. D., Rusinova-Videva S., Pavlova K., Kuncheva M., Panchev I., Dobreva S. Submerge culture process for biomass and exopolisaccharide production by Antarctic yeast: some engineering considerations. Applied Microbiology and Biotechnology, 2013, 97(12): 5303–5313.

How to Cite
VLAEV, Serafim Dimitrov et al. Structural anomalies in stirred submerged bioreactors relevant to immersed membrane use. Food Science and Applied Biotechnology, [S.l.], v. 1, n. 1, p. 56-62, mar. 2018. ISSN 2603-3380. Available at: <>. Date accessed: 25 apr. 2018. doi: