Biocalorimetry-supported analysis of fermentation processes

The close relation between metabolic activity and heat release means that calorimetry can be successfully applied for on-line monitoring of biological processes. Since the use of available calorimeters in biotechnology is difficult because of technical limitations, a new sensitive heat-flux calorimeter working as a laboratory fermenter was developed and tested for different aerobic and anaerobic fermentations with Saccharomyces cerevisiae and Zymommonas mobilis. The aim of the experiments was to demonstrate the abilities of the method for biotechnological purposes. Fermentations as well as the corresponding heat, substrate and product analyses were reproducible. During experiments the heat signal was used as a sensitive and fast indicator for the response of the organisms to changing conditions. One topic was the monitoring of diauxic growth phenomena during batch fermentations, which may affect process productivity. S. cerevisiae was used as the test organism and a protease-excreting Bacillus licheniformis strain as an industrial production system. Other experiments focused on heat measurements in continuous culture under substrate-limiting conditions in order to analyse bacterial nutrient requirements. Again, Z. mobilis was used as the test organism. Ammonium, phosphate, magnesium, biotin and panthothenate, as important substrate compounds, were varied. The results indicate that these nutrients are required in lower amounts for growth than formerly suggested. Thus, a combination of heat measurements and other methods may rapidly improve our knowledge of nutrient requirements even for a well-known microorganism like Z. mobilis. *** DIRECT SUPPORT *** AG903062 00004

[1]  C. Drainas,et al.  Growth requirements and the establishment of a chemically defined minimal medium inZymomonasmobilis , 1985, Biotechnology Letters.

[2]  I Boe,et al.  Cell counting and carbon utilization velocities via microbial calorimetry , 1990, Biotechnology and bioengineering.

[3]  E. H. Battley.  Energetics of Microbial Growth , 1987 .

[4]  O. Käppeli,et al.  Transient Responses of Saccharomyces uvarum to a Change of the Growth-limiting Nutrient in Continuous Culture , 1985 .

[5]  I. Marison,et al.  A calorimetric investigation of the aerobic cultivation of Kluyveromyces fragilis on various substrates , 1987 .

[6]  J A Roels,et al.  The inhibition of the maximum specific growth and fermentation rate of Zymomonas mobilis by ethanol , 1986, Biotechnology and bioengineering.

[7]  Ian W. Marison,et al.  Large-scale calorimetry and biotechnology , 1991 .

[8]  Frank A. J. L. James,et al.  The Development of the Laboratory , 1989 .

[9]  Bernhard Sonnleitner,et al.  Impacts of automated bioprocess systems on modern biological research , 1992 .

[10]  I. Wadsö.  Progress and problems in microcalorimetric work on mammalian cell systems , 1988 .

[11]  Réjean Samson,et al.  Flow microcalorimetry in monitoring biological activity of aerobic and anaerobic wastewater-treatment processes , 1988 .

[12]  J. G. Kuenen,et al.  Continuous measurement of microbial heat production in laboratory fermentors , 1993, Biotechnology and bioengineering.

[13]  I. Marison,et al.  The definition of energetic growth efficiencies for aerobic and anaerobic microbial growth and their determination by calorimetry and by other means , 1993 .

[14]  A. Blomberg,et al.  Use of microcalorimetric monitoring in establishing continuous energy balances and in continuous determinations of substrate and product concentrations of batch‐grown Saccharomyces cerevisiae , 1991, Biotechnology and bioengineering.

[15]  H. Lawford,et al.  Development of a simple defined medium for continuous ethanol production by Zymomonas mobilis , 2004, Biotechnology Letters.

[16]  G. Eigenberger,et al.  Biokalorimetrie : Methoden und Nutzungspotential , 1993 .

[17]  Günther W. H. Höhne,et al.  Calorimetry : fundamentals and practice , 1984 .

[18]  J. Luong,et al.  Heat Evolution During the Microbial Process — Estimation, Measurement, and Applications , 1983, Microbial Activities.

[19]  U. von Stockar,et al.  A unified stoichiometric model for oxidative and oxidoreductive growth of yeasts , 1992, Biotechnology and bioengineering.

[20]  Urs von Stockar,et al.  Application of bench-scale calorimetry to chemostat cultures , 1989 .

[21]  J. Russell.  Heat production by ruminal bacteria in continuous culture and its relationship to maintenance energy , 1986, Journal of bacteriology.

[22]  Ian W. Marison,et al.  The use of calorimetry in biotechnology , 1989 .

[23]  R. Bar.  Fermentation calorimetry vs microcalorimetry , 1988 .

[24]  D. Martens,et al.  Calorimetric control of fed‐batch fermentations , 1990, Biotechnology and bioengineering.

[25]  H W Doelle,et al.  Zymomonas mobilis--science and industrial application. , 1993, Critical reviews in biotechnology.

[26]  T. Jeffries,et al.  Respiratory efficiency and metabolite partitioning as regulatory phenomena in yeasts , 1990 .

[27]  Patrick N. Royce,et al.  A Discussion of Recent Developments in Fermentation Monitoring and Control from a Practical Perspective , 1993 .

[28]  H. Sahm,et al.  Zymomonas mobilis mutants blocked in fructose utilization , 2004, Applied Microbiology and Biotechnology.