Kinetic evaluation and modeling for batch degradation of 2-hydroxybiphenyl and 2,2′-dihydroxybiphenyl by Corynebacterium variabilis Sh42

abstract

This study evaluated the biodegradation kinetics of 2-hydroxybiphenyl (2-HBP) and 2,2′-dihydroxybiphenyl (2,2′-DHBP) with different initial concentrations range S₀ (5–50 mg/L) using suspended cultures of Corynebacterium variabilis Sh42 with fixed initial biomass concentration X₀ (315.8 mg/L) in a series of batch experiments. The cultures followed substrate inhibition kinetics. By fitting specific growth rates μ (h⁻¹) on suitable substrate inhibition models, biokinetic constants that are necessary to understand the kinetics of biodegradation process were evaluated by POLYMATH 6.1 software. Although Haldane and Yano and Koga (2) biokinetic equations for substrate inhibition seem to be the best adequate expressions for specific growth rates on 2-HBP and 2,2′-DHBP, respectively, an evident disagreement was observed between experimental and simulated profiles for bacterial growth X (mg/L) and substrate concentration S (mg/L). Correlation and simulation studies using a new proposed model based on modified Haldane equation gave better results.

Keywords:

• Corynebacterium variabilis
• Biodegradation
• 2-Hydroxybiphenyl
• 2,2′-Dihydroxybiphenyl
• Kinetics
• Modeling