Student Work

The effect of growth phase and cryopreservation on culture stability using Bacillus licheniformis as a producer of pol--glutamic acid


Bacillus licheniformis ATTC 9945A is a strain of bacteria capable of overproducing the anionic polymer poly--glutamic acid (PGA). The inability to obtain reproducible polymer production limits the usefulness of the production system in industrial processes. This project focuses on culture instability through multiple generations and the effect of growth phase prior to cryopreservation as one possible cause of this variation. Ten generations of cells, at three different phases of growth, were grown and stored at -80?C. These generations were then studied to identify variation in such key indicators as cell mass, viable cell and spore counts, degree of polymer yield, and molecular weight to determine whether the degree of passage has an effect on the cells ability to produce PGA. The data obtained through these studies showed a decline in the number of viable cells remaining at the end of each growth phase as the number of generations increased. Results also showed a significant difference in the production capabilities of the three growth phases.

  • This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.
  • 01E004M
  • 2001
Date created
  • 2001-01-01
Resource type
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