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Triclocarban (TCC), an antibacterial agent commonly used in personal care products, is one of the top ten contaminants of emerging concern in various environmental media, including soil and contaminated water in vadose zone. This study aimed to investigate TCC-contaminated water remediation using biochar-immobilized bacterial cells. Pseudomonas fluorescens strain MC46 (MC46), an efficient TCC-degrading isolate, was chosen, whereas agro-industrial carbonized waste as biochar was directly used as a sustainable cell immobilization carrier. According to the long-term TCC removal performance results (160 d), the biochar-immobilized cells consistently exhibited high TCC removal efficiencies (84–97%), whereas the free MC46 removed TCC for 76–94%. At 100 days, the detachment of the MC46 cells from the immobilized cell column was observed. The micro-Fourier-transform infrared spectroscopy results indicated that extracellular polymeric substance (EPS) was produced, but polysaccharide and protein fractions were washed out of the column. The lipid fraction of EPS adhered to the biochar, promoting TCC sorption for long-term treatment. The shortening of MC46 cells improved the tolerance of TCC toxicity. The TCC-contaminated water was successfully detoxified by the biochar-immobilized MC46 cells. Overall, the waste-derived biochar-immobilized cell system proposed in this study for the removal of emerging contaminants, including TCC, is efficient, economical, and aligned with the sustainable development concept of value-added utilization of waste. [Display omitted] • Long-term triclocarban (TCC) removal by the biochar-immobilized cells was 84–97%. • TCC degradation by free Pseudomonas fluorescens strain MC46 (MC46) was 76–94%. • MC46 produced extracellular polymeric substance (EPS) and promoted TCC adsorption. • Lipid from EPS coated on biochar, while polysaccharide and protein washed out. • Cell shrinkage enhanced TCC resistance, leading to the water detoxification. [ABSTRACT FROM AUTHOR]

Triclocarban (TCC) is a widely used antimicrobial agent and has been identified as a subsurface contaminant. This study demonstrates enhanced TCC remediation using biochar-immobilized cells. The influence of operating and environmental parameters (including initial TCC concentration, pH, cell loading, and co-carbon source concentration) on TCC removal was investigated using one-factor-at-a-time (OFAT) and response surface methodology (RSM) analyses to determine the TCC removal performance. Pseudomonas fluorescens strain MC46 (MC46) was selected and supported on biochar from carbonized residue of wood vinegar production. The OFAT and RSM of the operating and environmental parameters resulted in TCC removal efficiencies of between 30% and 83%. The initial TCC concentration (5 ̶ 20 mg L−1) significantly affected the removal rate (0.06 ̶ 9.23 mg L−1 d−1). The self-substrate inhibition kinetics followed a modified Edwards model with K i of 599.65 mg L−1. Compared to previous work, higher K i (less inhibition) were observed in this study and was due to the integration of biodegradation by MC46 and adsorption on the biochar-immobilized MC46. The biochar-immobilized cell technology is an efficient, sustainable, and economical method for future contaminant removal. [Display omitted] • Initial triclocarban (TCC) concentration influenced TCC removal rates. • The biochar-immobilized cells removed up to 96% of TCC. • The self-substrate inhibition kinetics followed a modified Edwards model. • Less inhibition was due to degradation and adsorption on biochar-immobilized MC46. [ABSTRACT FROM AUTHOR]

Triclocarban (TCC), an emerging endocrine disruptor, has been commonly found in municipal treated wastewater. Pseudomonas fluorescens MC46 (MC46), an effective TCC-degrading bacterium, could be applied to remove TCC from wastewater. In addition, application of a cell immobilization technique could possibly enhance its removal performance. This study examined microbial cells immobilized on waste biochar (from wood vinegar production) as a highly effective advanced wastewater treatment unit for TCC removal. TCC removal was investigated from real wastewater samples using the following treatments: biochar only, cell-immobilized biochar, and free cell systems in batch (short-term) and semi-batch (long-term) modes. The TCC adsorption capacities of original and potassium hydroxide-modified biochars (no cells) were 8.43 and 9.17 mg/g, respectively. During the batch experiment, the cell-immobilized modified biochar exhibited the highest TCC removal, 79.80%, in the model TCC solution. Five-cycle semi-batch experiments were utilized to investigate the reusability and performance of the treatment systems. After five cycles, the cell-immobilized modified biochar still achieved stable TCC removal (52%) due to the integration of adsorption and biodegradation. Free MC46 cells and biochars (no MC46 cells) only removed 32% and 2% of TCC, respectively, due to cell washout/death and sorbent exhaustion. This important work clearly demonstrates the significant potential for the future utilization of cell-immobilized biochars in a sustainable wastewater treatment system. Furthermore, the use of renewable agro-industrial wastes aid in the development of a strong circular bio-based economy. [Display omitted] • Real wastewater promoted TCC degradation by Pseudomonas fluorescens MC46 (MC46). • In semi-batch, cell-immobilized biochars had high TCC removal (up to 65%). • Reused cell-immobilized biochars gave more stable removal than biochars and MC46. • Cell-immobilized biochars detoxified TCC-contaminated treated wastewater. [ABSTRACT FROM AUTHOR]