Phenol biodegradation by plant growth promoting bacterium, S. odorifera: kinetic modeling and process optimization

Area of Science:

• Environmental microbiology
• Bioremediation
• Bacterial physiology

Background:

• Phenol is a significant organic pollutant from industrial activities.
• Bioremediation using microorganisms offers a sustainable solution for phenol-contaminated environments.
• Plant growth-promoting bacteria (PGPB) can enhance soil health and plant resilience.

Purpose of the Study:

• To investigate the phenol biodegradation kinetics of a newly isolated PGPB, Serratia odorifera.
• To determine the growth kinetics parameters of S. odorifera under phenol stress.
• To propose a phenol biodegradation pathway for S. odorifera and explore its potential in soil remediation.

Main Methods:

• Isolation and identification of Serratia odorifera from arable soil.
• Cultivation of S. odorifera in minimal medium with phenol as the sole carbon source.
• Application of the Haldane inhibition model to determine growth kinetics parameters (μmax, Ks, Ki).
• Fitting biodegradation data using the modified Gombertz model.
• Optimization of incubation temperature and pH for phenol biodegradation.

Main Results:

• S. odorifera exhibited significant phenol biodegradation capabilities.
• Key growth kinetics parameters were determined: μmax = 0.469 h⁻¹, Ks = 26.6 mgL⁻¹, Ki = 292 mgL⁻¹.
• Phenol concentration influenced biodegradation rate and lag time, with optimal conditions at 28°C and pH 7.0.
• A novel phenol biodegradation pathway for S. odorifera was proposed.

Conclusions:

• Serratia odorifera is a promising candidate for the bioremediation of phenol-contaminated soils.
• The study provides insights into the synchronization of phenol biodegradation and plant growth promotion by PGPB.
• This PGPB can mitigate plant stress in contaminated environments while enhancing soil quality.