Temperature profiles and alginate synthesis in mucoid and non-mucoid variants of Pseudomonas aeruginosa

Alginate-producing Pseudomonas aeruginosa 8821 spontaneously produced low- and high-alginate-producing variants that had low and high specific activities of GDP-mannose dehydrogenase and high and low specific growth rates, respectively. The optimal temperature for alginate production was 10°C below that for growth in the case of the high-producer but they were the same for the low-producer. In short duration thermal death experiments, alginate protected cells against lethal temperatures, although the maximal temperature for growth of the mucoid variants (43°C) was lower than that for the non-mucoid strain (44°C). The temperature profiles were associative and above 37°C growth concurred with thermal death.