Abstract
Rhizopus microsporus var. microsporus and var. oligosporus are used in the manufacture of various Asian fermented foods (tempe, black oncom, sufu). In view of solid-substrate fermentation (SSF) control, mycelial growth of strains of both varieties was tested for sensitivity to fluctuations of temperature, water activity and interstitial gas composition. This was achieved by measuring radial growth as well as biomass dry weight of pre-germinated microcolonies on defined media. The optimum conditions were temperature 40 °C, aw 0.995 and a gas composition of air for the growth of both strains on a model medium. Whereas radial growth rates of var. microsporus and var. oligosporus were similar, biomass growth rates of var. oligosporus were higher than those of var. microsporus under optimum conditions. The temperature-dependent growth of Rhizopus spp. at aw > 0.98 could be described by the Ratkowsky Equation. Carbon dioxide (5–10% v/v) inhibited the growth of Rhizopus spp. at non-limiting levels of oxygen. The two strains were able to grow at low (0.5% v/v) oxygen levels, but the mycelial density was rather low. No interrelation of water activity and gas composition was observed, but at high water activity the fungi were more sensitive to changes of temperature. The implications for process control are discussed.
Similar content being viewed by others
References
Cuppers, H.G.A.M., Oomes, S. & Brul, S. 1997 A model for the combined e.ects of temperature and salt concentration on growth rate of food spoilage molds. Applied and Environmental Microbiology 63, 3764-3769.
De Reu, J.C., Griffiths, A.M., Rombouts, F.M. & Nout, M.J.R. 1995 Effect of oxygen and carbon dioxide on germination and growth of Rhizopus oligosporus on model media and soya beans. Applied Microbiology and Biotechnology 43, 908-913.
Gervais, P., Bensoussan, M. & Grajek, W. 1988a Water activity and water content: comparative e.ects on the growth of Penicillium roqueforti on solid substrate. Applied Microbiology and Biotechnology 27, 389-392.
Gervais, P., Molin, P., Grajek, W. & Bensoussan, M. 1988b Influence of the water activity of a solid substrate on the growth rate and sporogenesis of fllamentous fungi. Biotechnology and Bioengineering 31, 457-463.
Hesseltine, C.W., Featherston, C.L., Lombard, G.L. & Dowell Jr, V.R. 1985 Anaerobic growth of molds isolated from fermentation starters used for foods in Asian countries. Mycologia 77, 390-400.
Mitchell, D.A., Greenfield, P.F. & Doelle, H.W. 1990 Mode of growth of Rhizopus oligosporus on a model substrate in solid state fermentation. World Journal of Microbiology and Biotechnology 6, 201-208.
Norrish, R.S. 1966 An equation for the activity coefficient and equilibrium relative humidities of water in confectionery syrups. Journal of Food Technology 1, 25-39.
Nout, M.J.R. & Rombouts, F.M. 1990 Recent developments in tempe research. Journal of Applied Bacteriology 69, 609-633.
Oriol, E., Raimbault, M., Roussos, S. & Viniegra-Gonzales, G. 1988 Water and water activity in the solid state fermentation of cassava starch by Aspergillus niger. Applied Microbiology and Biotechnology 27, 498-503.
Peñaloza, W., Davey, C. L., Hedger, J. N. & Kell, D. B. 1991 Stimulation by potassium ions of the growth of Rhizopus oligosporus during liquid-and solid-substrate fermentations. World Journal of Microbiology and Biotechnology 7, 260-268.
Ratkowsky, D.A., Olley, J., McMeekin, T.A. & Ball, A. 1982 Relationship between temperature and growth rate of bacterial cultures. Journal of Bacteriology 149, 1-5.
Ratkowsky, D.A., Lowry, R.K., McMeekin, T.A., Stokes, A.N. & Chandler, R.E. 1983 Model for bacterial culture growth rate throughout the entire biokinetic temperature range. Journal of Bacteriology 154, 1222-1226.
Rosso, L., Lobry, J.R. & Flandrois, J.P. 1993 An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. Journal of Theoretical Biology 162, 447-463.
Sarrette, M., Nout, M.J.R., Gervais, P. & Rombouts, F.M. 1992 Effect of water activity on production and activity of Rhizopus oligosporus polysaccharidases. Applied Microbiology and Biotechnology 37, 420-425.
Smits, J.P., Rinzema, A., Tramper, J., Van Sonsbeek, H.M., Hage, J.C., Kaynak, A. & Knol, W. 1998 The influence of temperature on kinetics in solid-state fermentation. Enzyme and Microbial Technology 22, 50-57.
Soccol, C.R., Raimbault, M. & Pinheiro, L.I. 1994 Effect of CO2 concentration on the mycelium growth of Rhizopus spp. Agricultural Biology and Technology 37, 203-210.
Su, Y-C. 1986 Sufu. In Legume-based Fermented Foods. eds. Reddy, N.R., Pierson, M.D. & Salunkhe, D.K. pp. 69-83. Boca Raton, Fl., USA: CRC Press. ISBN 0-8493-6286-5.
Zwietering, M.H., Cuppers, H.G.A.M., De Wit, J.C. & Van `t Riet, K. 1994a Evaluation of data transformations and validation of a model for the e.ect of temperature on bacterial growth. Applied and Environmental Microbiology 60, 195-203.
Zwietering, M.H., De Wit, J.C., Cuppers, H.G.A.M. & Van `t Riet, K. 1994b Modeling of bacterial growth with shifts in temperature. Applied and Environmental Microbiology 60, 204-213.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Han, BZ., Nout, R.M. Effects of temperature, water activity and gas atmosphere on mycelial growth of tempe fungi Rhizopus microsporus var. microsporus and R. microsporus var. oligosporus. World Journal of Microbiology and Biotechnology 16, 853–858 (2000). https://doi.org/10.1023/A:1008974621698
Issue Date:
DOI: https://doi.org/10.1023/A:1008974621698