Characteristics of a novel acid-resistant phenol-degrading bacterium Acinetobacter pittii Hly3: Adaptability, kinetics, degradation pathway and long-term performance

Abstract

The high concentration of phenol in wastewater significantly restrains bioremediation efficiency; intricate environmental conditions further increase the difficulty, constraining further application. In this work, a novel phenol-degrading Acinetobacter pittii Hly3, was isolated and its ability to degrade phenol, environmental adaptability, kinetics and application potential were studied. Strain Hly3 possessed a strong capability on the degradation of phenol (1700 mg L⁻¹ in 56 h) and could remove phenol at a wide range of pH, temperature, and NaCl concentrations, as well as the tolerance of metal ions. Particularly, the Hly3 showed stable cyclic performance. Mass balance and stoichiometric analysis revealed 0.7935 g g⁻¹ conversions of phenol to biomass. Simultaneously, the growth and phenol degradation aligned well with the Haldane model. The degradation pathway demonstrated that phenol hydroxylase (PH) and 2,3-dioxygenase (C23O) were the key enzymes for phenol degradation. In addition, seed germination indicated that the degradation of phenol by Hly3 was an effective detoxification process, which reduced the biological accumulation of phenol in mung bean plants. Therefore, the highly tolerant strain Hly3 could be utilized to treat high-phenol wastewater in high-salt and acidic environments and this study has enriched the knowledge related to Acinetobacter pittii in managing phenol-contaminated environments.