Affiliations 

  • 1 Universiti Putra Malaysia
  • 2 Universiti Malaysia Perlis
MyJurnal

Abstract

The pollution of heavy metals and toxic xenobiotics has become a central issue worldwide.
Bioremediation of these toxicants are being constantly carried out using novel microbes.
Molybdenum reduction to molybdenum blue is a detoxification process and mathematical
modelling of the reduction process can reveal important parameters such as specific reduction
rate, theoretical maximum reduction and whether reduction at high molybdenum concentration
affected the lag period of reduction. The used of linearization method through the use of natural
logarithm transformation, although popular, is inaccurate and can only give an approximate
value for the sole parameter measured; the specific growth rate. In this work, a variety of
models for such as logistic, Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy,
Buchanan three-phase and more recently Huang were utilized for the first time to obtain values
for the above parameters or constants. The modified Gompertz model was the best model in
modelling the Mo-blue production curve from Serratia marcescens strain DR.Y10 based on
statistical tests such as root-mean-square error (RMSE), adjusted coefficient of determination
(R2), bias factor (BF), accuracy factor (AF) and corrected AICc (Akaike Information Criterion).
Parameters obtained from the fitting exercise were maximum Mo-blue production rate (μm), lag
time (l) and maximal Mo-blue production (Ymax) of X (h-1), Y (h) and Z (nmole Mo-blue),
respectively. The application of primary population growth models in modelling the Moblue
production rate from this bacterium has become a successful undertaking. The model
may also be used in other heavy metals detoxification processes. The parameters
constants extracted from this work will be a substantial help for the future development
of further secondary models.