Prediction of growth kinetics of Bacillus tequilensis in nutrient broth under isothermal and non-isothermal conditions

Abstract

The main objective of the present study was to develop and validate a new alternative modelling method to predict Bacillus tequilensis count in nutrient broth under iso-thermal and non-isothermal conditions. The bacterial growth data of Bacillus tequilensis was obtained experimentally in aerobically-kept nutrient broth medium and described with two-step and one-step modelling approaches by different primary models (the modified Gompertz, logistic, Baranyi and Huang models) under isothermal temperatures. Temperature-dependent kinetic parameter (maximum specific growth rate ‘µ_max’) was described as a function of temperature via the Ratkowsky model integrated with each primary model. The Huang model based on the one-step modelling approach yielded the best fitting results (RMSE = 0.143 and adjusted-R² = 0.977) for all isothermal conditions. Therefore, the Huang model was also used to check it’s prediction capability under non-isothermal conditions. The differential form of the Huang model provided satisfactorily statistical indexes (B_f = 1.07 and A_f = 1.08) indicating reliably being able to use to describe the growth behaviour of Bacillus tequilensis in broth subjected to non-isothermal conditions.

Keywords:
dynamic condition; microbiological quality; Bacillus tequilensis; growth kinetic; predictive microbiology