Bio-based and cost effective method for phenolic compounds removal using cross-linked enzyme aggregates

• Published in: Journal of hazardous materials 2021-02, Vol.403, p.124021-124021, Article 124021
• Main Authors: Sellami, Kheireddine, Couvert, Annabelle, Nasrallah, Noureddine, Maachi, Rachida, Tandjaoui, Nassima, Abouseoud, Mahmoud, Amrane, Abdeltif
• Format: Article
• Language: English
• Subjects: Chemical Sciences; CLEAs; Cost-Benefit Analysis; Cross-Linking Reagents; Enzymatic transformation; Enzyme Stability; Enzymes, Immobilized - metabolism; Glutaral; Green process; Hydrogen-Ion Concentration; Peroxidase immobilization; Phenols; Temperature
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.124021

This work aimed at presenting a green method using a new source of peroxidase isolated from Raphanus sativus var. niger (RSVNP) in immobilized form, for the treatment of wastewater. To ensure stability and enzymatic activity in the biodegradation process, RSVNP was immobilized as a cross-linked enzyme aggregate (CLEAs). With more than 29% of recovered activity and 85% aggregation yield, acetone was selected as the best precipitating agent. The formed protein aggregates required 2% (v/v) of glutaraldehyde (GA) concentration and a ratio of 9:1 (v/v) enzyme (E) amount to cross-linker (E/GA). Compared to the free enzyme, RSVNP-CLEAs were found more chemically and thermally stable and exhibited good storage stability for more than 8 weeks. In addition, RSVNP-CLEAs were evaluated for their ability to remove phenol and p-cresol from aqueous solution by varying several operating conditions. A maximal yield (98%) of p-cresol conversion was recorded after 40 min; while 92% of phenol was degraded after 1 h duration time. The reusability of RSVNP-CLEAs was tested, displaying 71% degradation of phenol in the third batch carried out and more than 54% was achieved for p-cresol after four successive reuses in the presence of hydrogen peroxide at 2 mM concentration. [Display omitted] •A new source of peroxidase was immobilized for phenolic compounds treatments. •Crosslinked peroxidase showed better physical and thermal stability compared to the free enzyme. •Immobilized peroxidase retained 100% activity after storage at 4 °C for 8 weeks. •RSVNP-CLEAs were able to remove 92% of phenol and 98% of p-cresol. •More than 71% degradation of phenols was achieved after 3 successive reuses.