Effect of temperature, growth rate, and nutrient limitation on the yield and composition of three bacterial isolates from an arctic soil grown in continuous culture

• Published in: Canadian Journal of Microbiology
• Main Author: Nelson, Louise M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1978
• Subjects: Genetics; Molecular Biology; Applied Microbiology and Biotechnology; General Medicine; Immunology; Microbiology; Arctic
• Online Access: http://dx.doi.org/10.1139/m78-234; http://www.nrcresearchpress.com/doi/pdf/10.1139/m78-234

Three bacterial isolates from an arctic meadow soil, Pseudomonas M216, Bacillus M153, and Arthrobacter M51, were grown continuously in carbon-and nitrogen-limiting media at 15 and 5 °C at three dilution rates from 0.04 to 0.01 h −1 . Measurements of yield, viability, endogenous oxygen-uptake rate, and cell composition indicated that in general, these isolates were well adapted for growth at low rates and low temperature under nutrient limitation. Changes in cell composition with temperature, growth rate, and nutrient limitation followed patterns similar to those observed in organisms studied in other laboratories. Yields were higher at 15 than at 5 °C in Pseudomonas M216 and Arthrobacter M51 and the endogenous respiration rate tended to decrease with decreasing dilution rate. Substrate affinity (K s ) and μ max varied with temperature, and Pseudomonas M216 exhibited the lowest K s for carbon and nitrogen and highest μ max under the growth conditions studied, except at 15 °C under carbon limitation where Arthrobacter M51 exhibited the lowest K s . Only Bacillus M153 exhibited a significant loss in viability at low dilution rates and a detectable specific maintenance rate (0.0077 h −1 ), factors which may contribute to the low isolation frequency of the genus at the meadow site.