L-Pyroglutamate (PGA) is naturally occurring from L-glutamate solution with accelerated formation rate under high temperature and
low pH. Even though PGA has been identified as a neurotoxic agent on brain cells, the effect of PGA on the growth of microorganisms is
rarely known. Here various kinds of microorganisms differing in their optimal growth temperature, pH, phylogeny, and isolated biotope
were investigated for the effect of PGA. We found that growth of thermoacidophiles, including both archaea and bacteria, was seriously
inhibited by the presence of PGA, and the extent of the inhibitory effect was closely related with growth temperature and pH.
Interestingly, only microbes that grow at high temperature and low pH are inhibited by PGA, while this compound may stimulate growth
rates of organisms that live at neutral pH and low temperature.
6 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.