Abstract
A novel principle for mixing and aeration in stirred bioreactors, named Variomixing, was developed. Four baffles are rotated intermittently at a rotational speed slower or similar to the speed of a centrally placed axial flow impeller. Rotational speeds of the baffles and impeller of 5–10 and 500–600 rpm, respectively, results in the highly turbulent flow regime characteristic of conventional bioreactors with high mixing and mass transfer capacities. Stagnant zones around crevices and crannies in which wall growth may commence are avoided since the baffles are never completely at rest. Increasing the rotational speed of the baffles (5 s every 5 min), so that it follows the speed of the impeller (500–600 rpm), cancels the effect of the baffles and a deep vortex and high peripheral liquid flow rates at the reactor wall develop. The vortex ensures that also the head-space of the reactor wall is flushed and any deposits removed. The filamentous fungus Aspergillus oryzae has been grown in batch cultures in the Variomixing bioreactor. Compared to conventional laboratory-scale bioreactors, in which more than 30% of all biomass was found attached to walls, less than 2% of the total A. oryzae biomass was found on the walls in the Variomixing bioreactor.
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References
Bergmeyer HU, Bernt E, Schmidt F, Stork H (1974) D-glucose, determination with hexokinase and Glucose-6-phosphate dehydrogenase. In: Bergmeyer HU (editor) Methods of enzymatic analysis, vol 3, 2nd edn. Academic, New York, pp 1196–1201
Bull AT, Trinci APJ (1977) The physiology and metabolic control of fungal growth. In: Rose AH and Temptest DW (eds) Advances in Microbial Physiology, Vol. 15. Academic, London, pp 1–84
Castrillo JI, de Miguel I, Ugalde UO (1995) Proton production and consumption pathways in yeast metabolism. A chemostat culture analysis. Yeast 11:1353–1365
Degn H, Nielsen JB (1987) A general purpose serial interphase for the laboratory computer. Binary 10:25–28
Doran PM (1995) Bioprocess engineering principles. Academic, London
Emerson R (1941) An experimental study of the life cycles and taxonomy of allomyces. Lloydia 4:77–144.
Iversen JJL, Thomsen JK, Cox RP (1994) On-line growth measurements in bioreactors by titrating metabolic proton exchange. Appl Microbiol Biotechnol 42:256–262.
Linton JD, Austin RM and Haugh DE (1984) The kinetics and physiology of stipitatic acid and gluconate production by carbon sufficient cultures of Penicillium stipitatum growing in contuous culture. Biotechnol Bioeng 26:1455–1464.
Mackereth FJH (1964) An improved galvanic cell for determination of oxygen concentrations in fluids. J Sci Instrum 41:38–41
Mackereth FJH, Heron J, Talling JF (1978) Water analysis: some revised methods for limnologists. Freshwater biological association, Ambleside
Metz B, Kossen NWF (1977) The growth of molds in the form of pellets—a literature review. Biotechnol Bioeng 19:781–799
Pirt SJ (1966) A theory of the mode of growth of fungi in the form of pellets in submerged culture. Proceedings of the Royal Society, B. 166:369–373
Pirt SJ (1975) Principles of microbe and cell cultivation. Blackwell Scientific, Oxford
Poulsen BR, Ruijter GJG, Visser J, Iversen JJL (2003) Determination of first order rate constants by Log of Slope plot applied to Aspergillus niger batch cultures. Biotechnol Lett 25:565–571
Prosser JI (1994) Kinetics of filamentous growth and branching. In: Gow AR, Gadd GM (eds) The growing fungus. Chapman and Hall, pp 301–335
Scarborough GA (1970) Sugar transport in Neurospora crassa. J Biol Chem 245:1694–1698
Schneider RP, Wiley WR (1971) Kinetic characteristics of the two glucose transport systems in Neurospora crassa. J Bacteriol 106:479–486
Schrickx JM, Krave AS, Verdoes JC, Hondel CAMJJ van den, Stouthamer AH, Verseveld HW van (1993) Growth and product formation in chemostat and recycling cultures by Aspergillus niger N402 and a glycoamylase overproducing transformant, provided with multiple copies of the glaA gene. J Gen Microbiol 139:2801–2810
Solomons GL (1980) Fermenter design and fungal growth. In: Smith JE, Berry DR, Kristiansen B (eds) Fungal biotechnology. Academic, London, pp 55–79
Swift RJ, Wiebe MG, Robson GD and Trinci APJ (1998) Recombinant glucoamylase production by Aspergillus niger B1 in chemostat and pH auxostat cultures. Fungal Genet Biol 25:100–109
Topiwala HH, Hamer G (1971) Effect of wall growth in steady-state continuous culture. Biotechnol Bioeng 13:919–922
Torres NV, Riol-Cimas JM, Wolschek M, Kubicek CP (1996) Glucose transport by Aspergillus niger: the low-affinity carrier is only formed during growth on high glucose concentrations. Appl Microbiol Biotechnol 44:790–794
Walker JAH, Holdsworth H (1958) Equipment design. In: Steel R (ed) Biochemical engineering. Heywood, London, pp 223–273
Wiebe MG and Trinci APJ (1991) Dilution rate as a determinant of mycelial morphology in continuous culture. Biotechnol Bioeng 38:75–81
Withers JM, Wiebe MG, Robson GD, Trinci APJ (1994) Development of morphological heterogeneity in glucose-limited chemostat cultures of Aspergillus oryzae. Mycol Res 98:95–100
Acknowledgements
We thank Svend Aage Madsen and Erling Knudsen for expert technical assistance and Marilyn G. Wiebe for reading the manuscript. Contract grant sponsors: The Danish Research Councils, Novo Nordisk A/S.
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Larsen, B., Rask Poulsen, B., Eriksen, N.T. et al. Homogeneous batch cultures of Aspergillus oryzae by elimination of wall growth in the Variomixing bioreactor. Appl Microbiol Biotechnol 64, 192–198 (2004). https://doi.org/10.1007/s00253-003-1437-x
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DOI: https://doi.org/10.1007/s00253-003-1437-x