Biodegradation of dual phenolic substrates in simulated wastewater by Gliomastix indicus MTCC 3869

• Substrate degradation with incorporation of maintenance energy expenditure has been modeled.
• The biodegradation dynamics has been modeled in the two dual substrate systems.
• Quantitative assessment of interaction parameters in two dual substrate systems.
• p-Cresol degradation is difficult in presence of phenol whereas resorcinol shows reverse effect.

The biodegradation of phenol, resorcinol, and p-cresol by Gliomastix indicus was carried out by conducting batch experiments in single and the dual substrate systems: phenol–p-cresol, and phenol–resorcinol, at various initial concentrations in simulated aqueous solution. The growth kinetic model was selected and interaction parameters were estimated. Competitive inhibition type of substrate interaction was involved in this dual substrate systems. The interaction parameter values were found as Ia,1 = 0.044,  Ia,2 = 1.17 for phenol–p-cresol, and Ia,1 = 1.09, Ia,2 = 0.052 for phenol–resorcinol system. The variation in maintenance energy expenditure with specific growth rate was incorporated to model specific degradation rate. A linear model for specific degradation rate was developed for single substrate system, while a non linear model was developed for dual substrate system. A set of model equations was proposed and solved to describe the biodegradation dynamics of substrates in the two dual substrate systems. The simulation results were found to be consistent with the experimental data.