Growth characteristics of E. coli and B. subtilis cultured on an agar substrate in microgravity

M. Kacena, P. Todd

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Previous space-flight experimentation has shown that suspension cultures of bacteria exhibit increased growth in the weightless, space-flight environment. To the contrary, the E. coli and B. subtilis cells grown on solid agar did not experience a heightened final cell concentration when cultured in space. It does, however, appear that changes in other growth characteristics of bacteria might occur when grown under various gravitational conditions. In order to further analyze the growth characteristics of bacteria under different graritational environments, E. coli and B. subtilis were cultured on agar under several inertial loadings: static 1 g, clino-rotated, and reduced gravity aboard Space Shuttle mission STS-63. Several different growth durations were chosen to better examine the first three stages of bacterial growth: lag phase, log phase, and saturation phase. After appropriate growth periods the cultures were terminated with a 2% glutaraldehyde solution, the fixed bacteria were resuspended from the agar with a non-lytic surfactant, and individual cells were counted via hemacytometer. From the growth durations and the final cell concentrations [cells/ ml], an initial plot of the growth curve was established. Then growth kinetic values were obtained using the Marquardt-Levenberg least squares fitting algorithm in conjunction with bacterial growth kinetic equations. From this analysis technique it is concluded that E. coli and B. subtilis cultured on agar have a shortened lag phase duration when grown in space flight and in clinostats. Furthermore, saturation cell concentration, lag phase cell concentration, and growth rate appear to remain unchanged by gravitational environments.

Original languageEnglish (US)
Pages (from-to)58-62
Number of pages5
JournalMicrogravity Science and Technology
Volume10
Issue number1
StatePublished - Dec 1 1997
Externally publishedYes

ASJC Scopus subject areas

  • Modeling and Simulation
  • Engineering(all)
  • Physics and Astronomy(all)
  • Applied Mathematics

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