Immobilized enzyme with sustainable chestnut biochar to remediate polycyclic aromatic hydrocarbons contaminated soils

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) contaminated soil severely and are difficult to remediate. In this study, acid-modified chestnut inner shell biochar with abundant pore channels was used as the main raw materials for the immobilization of white-rot fungal crude enzyme. The maximum immobilization rate of crude enzymes (97.25%±6.20%) could be achieved under the optimal conditions of 24 h immobilization of 10 U/mL crude enzymes by 1 g biochar at 25℃ and pH = 5. Meanwhile, immobilization improved the stability of the crude enzyme. The relative activity of the immobilized crude enzyme increased by 59.32% and 49.73% (compared to the free crude enzymes) after 5 weeks of storage at 4°C and 25°C, respectively. It has been verified that chestnut-based immobilized crude enzyme can degrade 37% of benzo[a]pyrene in 10 days for PAHs-contaminated soils. An efficient, feasible, and low-cost remediation method for PAHs-contaminated soils was explored, which provides technical support for the application of crude enzymes in organic contaminated soils.

GRAPHICAL ABSTRACT

KEYWORDS:

• White rot fungus
• immobilized crude enzymes
• chestnut-based biochar
• polycyclic aromatic hydrocarbons
• benzo[a]pyrene

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics approval

Not applicable. This manuscript does not involve researching about humans or animals.

Additional information

Funding

The authors gratefully acknowledge the financial supports by the National Key R & D Program of the Science and Technology of China [grant no 2020YFC1808801].