Study on the effect of pH and temperature on growth of Pseudomonas sp. in the presence heavy metals
By: Naseem Kausar, Samina Qamer
Key Words: Heavy metal, Temperature, pH, Growth, Pseudomonas.
Int. J. Biosci. 9(6), 204-212, December 2016.
The Purpose of present study was to investigate the effect of Cr+2 and Pb+2 on heavy metal tolerant species of Pseudomonas at different pH and temperature for varying incubation periods.It was found that growth of Pseudomonas sp. increased in acidic medium (5.0-6.0) in presence of both metals (Cr+2 and Pb+2). In presence of chromium metal, Pseudomonas sp. showed maximum growth at pH 6.0. At pH 7.0, bacterial growth was gradually declined in Chromium enriched medium while accelerated up to maximum point in presence of Lead. Therefore, 6.0 and 7.0 were considered optimum pH values for highest bacterial growth in Chromium and Lead containing media respectively. In case of temperature, Pseudomonas sp. exhibited increase in growth only at 50°C in presence of Chromium and remained suppressed at all other selected temperatures (20ºC, 25ºC, 37ºC and 45º). In presence of Lead, Pseudomonas sp. showed significant growth at all selected temperatures (25ºC, 37ºC, 45ºC and 50ºC) except 20ºC. Optimum temperature values found for bacterial growth in Chromium and Lead medium were50ºC and 37ºC, respectively.Under optimum conditions, highest growth of pseudomonas sp. was observed within three days (72 hours) of incubation for both metals.