DefinePK

Abstract

A dynamic relationship exists between environmental conditions and the growth pattern of filamentous fungi. Growth kinetics such as the relationship between specific growth rate and the concentration of a substrate is one of the basic tools in microbiology. In such cases, a direct monitoring of the cell morphology and biomass distribution in the culture medium is potential. Hence the present work attempt to study the nutrient uptake and cell growth kinetics of a non-pathogenic fungus Aspergillus oryzae possessing the ability of bioremediation in the wasteful industrial rubber effluent. Four different models of Monod, Contois, Verhulst, and Tessier were used to investigate the cell growth kinetics in batch submerged fermentation process carried out in shake flasks. The compatibility of the experimental data fitted with Contois, Verhulst and Tessier models with the regression values are 0.65, 0.80, 0.21 and 0.84 respectively. Although Verhulst and Contois are the most suitable kinetic models to describe substrate utilization and cell growth behavior of filamentous fungi in submerged culture, the Tessier model was found best fitted with the experimental data. In the case of Monod, the maximum specific growth rate, µm and the half saturation constant, Ks were determined as 2.3 day-1 and 4.84 g/l respectively. For Verhulst, the maximum specific growth rate, µm and maximum biomass, Xm in terms of cell dry weight were determined as 0.9 day-1 and -1.5 g/L respectively. For Contois, µm was 3.4 day-1 and Ks was obtained as 4.04 g/L. However, in Tessier model, µm was determined to be 1.1 day-1 while the Ks was 54.05 g/l.