An Exploratory Study of Hydrochar as a Matrix for Biotechnological Applications.

Area of Science:

• Biomass Conversion and Biorefining
• Materials Science
• Biocatalysis

Background:

• Hydrothermal carbonization (HTC) offers a pathway for biomass valorization into hydrochar.
• Protein separation and enzyme immobilization are critical steps in biorefinery processes.
• Enzyme deactivation is a major limitation in cellulose-to-sugar bioconversions.

Purpose of the Study:

• To investigate hydrochar's potential for protein adsorption and enzyme immobilization.
• To evaluate the performance of immobilized enzymes in a biorefinery context.
• To explore non-energy applications of HTC-derived hydrochar.

Main Methods:

• Hydrochar production from silver fir via HTC followed by KOH activation.
• Adsorption experiments with bovine serum albumin (BSA) to determine protein-hydrochar interactions.
• Immobilization of β-glucosidase onto hydrochar and assessment of its enzymatic activity and stability.
• Kinetic analysis using Sip's isotherms for protein adsorption.

Main Results:

• Hydrochar demonstrated high adsorption capacity for BSA (≤3300 mg/g), well-fitted by Sip's isotherms.
• Hydrochar successfully immobilized β-glucosidase (≤26 w/w%), significantly enhancing operational stability (24x).
• The immobilized enzyme system showed improved stability compared to soluble enzymes, addressing a key bioconversion bottleneck.

Conclusions:

• Hydrochar is a promising material for protein separation and enzyme immobilization in biorefineries.
• HTC-derived hydrochar can enhance the efficiency and stability of biocatalytic processes.
• This study supports integrated process schemes combining HTC with industrial bioconversions.