Abstract:
Achromobacter xylosoxidans is one of the bacterial strains that have the capability to degrade butyric acid which
significantly contribute to malodours from pit latrines emissions. There is an increasing interest in being able
to predict the consequences of its growth on butyric acid degradation for remediation of malodour emissions
from pit latrines. The objective of this work was to elucidate the effect of temperature on butyric acid degradation
by A.xylosoxidans and to estimate microbiologically relevant parameters at dissimilar isothermal conditions
under batch conditions. The experiments were carried out by inoculating 1 mL of bacterial culture into 150 mL
each of MSM supplemented with 1,000 mgL-1 of butyric acid as a sole carbon source in a sterile 250
mL Erlenmeyer volumetric flask in triplicates. The temperatures were set at 25, 30, 35 and 40 oC with initial
medium pH of 7 and at agitation rate of 110 rpm. The values of microbiological parameters were obtained by
the application of modified Gompertz and modified Logistic sigmoidal models. It was found that the bacterial
strain was able to utilise butyric acid as a sole source of carbon at a wide range of temperatures. Both models
fitted described most of the experimental data sufficiently to each individual growth curve. The values of the
maximum growth rate () and lag time () obtained using the modified logistic model were higher than the
modified Gompertz model. In the cases investigated, the modified logistic model was statistically sufficient to
describe the growth data of A. xylosoxidans and its application was easy.
