Screening and evaluation of phenol utilization and growth in Acinetobacter baumannii W29 of wastewater

Phenols are ubiquitous pollutants, mainly from industrial effluent, causing pollution of natural water resources. The research focused on screening efficient phenol-degrading bacteria and kinetic modelling of phenol biodegradation and growth. Membrane filtration was used for the isolation of bacteria from the wastewater sample. The screening of phenol-degrading bacteria was based on the efficiency of phenol utilization. The strain with efficient phenol degradation capacity was characterized by 16S rDNA sequencing and designated Acinetobacter baumannii W29. Biomass growth and phenol utilization rate of the strain were evaluated at different initial phenol concentrations (100-800 mgL-1). Specific growth rate data were fitted to five models, i.e. Monod, Haldane, Aiba, Teisser, and Webb model. The yield coefficient at different initial phenol concentrations was calculated from the slope of the specific growth rate (μ) versus the specific phenol utilization rate (q). The strain showed complete phenol degradation potential up to 1000 mgL-1. The maximal growth rate was achieved at 400 mgL-1 , which coincided with the maximum substrate utilization rate at the same concentration. The specific growth rate showed the best fit with the Haldane model. The strain had a yield coefficient of 0.70 (mg cell mg-1 phenol). The value of µ and Ks revealed the affinity of the strain for high-concentration phenol and the its ability to withstand high phenol concentrations. The kinetic growth behaviour of the strain fitted well with the Haldane model. The findings of the study could be applied to wastewater treatment with a high phenol load.