Influence of Triton X-100 on growth of Pseudomonas putida No. 69-3, an n-heptanol-tolerant variant of an organic solvent-sensitive bacterium, Pseudomonas putida No. 69

 When Pseudomonas putida No. 69-3 cells, changed as an organic solvent-resistant variant from an organic solvent-sensitive parent, Pseudomonas putida No. 69, were cultivated with 0.01% surfactants, Triton X-100 provided the highest cell growth in the presence of 10% n-heptanol. When strain No. 69-3 was cultivated in a medium containing 10% n-heptanol and various concentrations of Triton X-100, 0.01% Triton X-100 gave the most improved cell growth. Hydrophobicity of the cell membrane did not change in the presence or absence of Triton X-100. However, when strain No. 69-3 was cultivated in a medium containing 0.01% Triton X-100 or without Triton X-100 and the culture broth was centrifuged at 500×g, the decrease in optical density of the supernatant was smaller when the cells were cultivated in a medium containing 0.01% Triton X-100 than when cultivated without Triton X-100. This result suggests that Triton X-100 decreased the degree of aggregation and improved growth. Received: 15 May 1998 / Accepted: 30 September 1998