A continuous culture study of an obligately psychrophilic Pseudomonas species

✍ Scribed by Harder, W. ;Veldkamp, H.

• Book ID: 104760567
• Publisher: Springer-Verlag
• Year: 1967
• Weight: 435 KB
• Volume: 59
• Category: Article
• ISSN: 0003-9276
• DOI: 10.1007/bf00406323

✦ Synopsis

The optimum temperatures for growth and respiration of an obligately psychrophilic Pseudomonas spec. were 14~ and 23 ~ C, respectively. The maximum temperature for growth was between 19 and 20 ~ C. When cells were grown in a chemostat with lactate as the growth-limiting substrate at a specific growth rate of 0.05 hr -1 over a temperature range of 5--19 ~ C, it was found that RNA concentration was lowest at 14 ~ C. At lower temperatures the cells compensated the decrease of reaction rates by increasing the concentration of RNA and of respiratory enzymes. A temperature raise above 14 ~ C also increased cellular RNA, which probably counteracted an impairment of protein synthesis. Above 18 ~ C the RNA increase ceased, resulting in a rapid decrease of protein synthesis, until between 19 and 20 ~ C growth ceased entirely. Cells grown at 14 ~ C showed a linear increase of RNA content and Qo~ values with growth rate, when this was varied from 0.025 to the maximum value of 0.2 hr -1.