Microcalorimetric performance of the growth in culture of Escherichia coli, Proteus mirabilis and their mixtures in different proportions

• Published in: Journal of thermal analysis and calorimetry 2014-04, Vol.116 (1), p.107-112
• Main Authors: Vazquez, C., Lago, N., Mato, M. M., Casas, L. M., Esarte, L., Legido, J. L., Arias, I.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Bacteria; Calorimetry; Chemical and Process Engineering; Chemistry; Chemistry and Materials Science; Engineering Sciences; Enterobacteriaceae; Escherichia coli; Growth; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Physiological aspects; Polymer Sciences; Proteus mirabilis
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-013-3535-z

Microcalorimetry is a technique that determines the heat flow produced as a result of microbial activities. The heat variations resulting from chemical reactions, which take place during metabolism, can be used to monitor bacterial growth in a culture medium. However, there are very few studies using calorimetry to investigate the relationships between two bacteria. In this work, we studied the interaction between E. coli and P. mirabilis , two bacteria belonging to the family Enterobacteriaceae . We have prepared three samples, mixing both enterobacteria at a concentration of 10 3  CFU mL −1 but in different proportions. Experimental equipment used was a Calvet microcalorimeter, where a constant temperature of 309.65 K was maintained. Then, we compared the shape of the heat flow–time curves of single microorganisms and their mixtures. Also, we calculated the thermokinetic parameters such as growth constant ( k ), generation time ( G ), detection time ( t d ) and the amount of heat released ( Q ). The results obtained showed that when E. coli and P. mirabilis were put together in the culture medium, the growth profile of P. mirabilis seemed to dominate, even at low proportions in the sample.