Masters Theses

Date of Award

3-1984

Degree Type

Thesis

Degree Name

Master of Science

Major

Chemical Engineering

Major Professor

George C. Frazier

Abstract

The purpose of this study was to determine the effects of temperature and pH on the degradation rate of phenanthrene by a Beijerinckia sp.

Batch experiments were employed for the experimentation with a growth medium consisting of basic mineral salts, yeast extract (0.5 grams/liter), phosphate buffer (0.1 molar) and approximately 1.29 ppm phenanthrene.

The effects of temperature at a pH of 7.0 on the specific growth rate of the Beijerinckia was Arrhenius in form exhibiting an "activation energy" of growth of approximately 16 kilocalories/ gram-mole. The effect of temperature on phenanthrene degradation rate was non-Arrhenius, with phenanthrene degradation commencing at a temperature of approximately 19 °C and increasing rapidly to a temperature of approximately 25 °C. Between the temperatures of 25 °C and 29 °C the degradation rate remained essentially constant, and once the temperature was greater than 29 °C, the degradation rate declined rapidly. The maximum cell specific growth rate of 0.730 (hours)-1 occurred at 30 °C ± 2 °C and a pH of 7.0 ± 0.20. The maximum phenanthrene degradation rate of 3.59 x 10-11 milligrams of phenanthrene/cell hour occurred at 26 °C ± 2 °C and a pH of 7.0 ± 0.20.

The pH behavior of the experimental system at 25 °C exhibited a sharp maximum in terms of both specific growth rate and iv phenanthrene degradation rate. The optimum pH for growth and phenanthrene degradation was 7.0 ± 0.2.

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