Faculty Advisor

Dilorio, Alexander A.


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.


Worcester Polytechnic Institute

Date Accepted

January 2001



Project Type

Major Qualifying Project


Restricted-WPI community only

Advisor Department

Biology and Biotechnology