Textile industry wastewater leads to significant environmental and public health challenges due to the presence of hazardous synthetic dye molecules, thereby demanding effective and innovative remediation strategies. Herein, the potential of novel, thermostable cellulases from Myceliophthora thermophila for the production of cellulose nanofibers (CNFs), a high-value biomaterial using sugarcane bagasse, is presented for the first time. The average diameter of CNFs was calculated to be 20.77 ± 1.11 nm. The CNFs were a stable suspension as indicated by the zeta potential value of − 27.2 mV. The obtained CNFs exhibited a thermal degradation onset temperature of ∼ 205 °C and a crystallinity degree value of ∼ 50.78%. The CNF film demonstrated high tensile strength and BET-specific surface area of 134.603 MPa and 7.5816 m2 g−1, respectively. The CNFs were successfully demonstrated as a nanoadsorbent for Congo red (CR) dye adsorption from the aqueous solution with a maximum removal percentage of 95.98% at nanoadsorbent dose = 175 mg, initial dye concentration = 116.54 mg L−1, pH = 3, contact time = 35 min and temperature = 29 °C using central composite design in response surface methodology. The adsorption equilibrium data was found to fit best with the Langmuir isotherm model. The maximum monolayer adsorption capacity was calculated to be 80.84 mg g−1 which was in good agreement with the experimental value. The adsorption kinetic data was found to be described by a pseudo-second-order kinetics model (R2 = 1). The adsorption process was endothermic and spontaneous according to the thermodynamic parameters. Based on our findings, the proposed mechanisms of adsorption include electrostatic interactions between positively charged CNF surface and negatively charged CR dye, hydrogen bonding, chemisorption, and physisorption. The synthesized CNF nanoadsorbent also demonstrated high CR removal efficiency of up to 90.45% and 84.68% in Yamuna River water and textile effluent real water samples. The synthesized CNF nanoadsorbent exhibited more than 90% recyclability during seven consecutive adsorption–desorption cycles. Additionally, the dye-adsorbed CNF nanoadsorbent was also successfully demonstrated as a pH monitoring strip. Hence, the present study represents waste-to-wealth innovation by turning agricultural waste into low-cost, high-value CNFs and reusing dye-adsorbed CNF nanoadsorbent for pH monitoring in various applications. Additionally, the present study also enables the sustainable integration of the production of nanocellulose and biofuels by these thermostable enzymes, which provide significant benefits as compared to conventional separate production methods.

Cellulose nanofiber production using novel thermostable cellulases and response surface modeling for optimization of Congo red dye removal

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发表日期：

2025年6月17日

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Twinkle Gupta,
Shilpa Sharma

摘要

Textile industry wastewater leads to significant environmental and public health challenges due to the presence of hazardous synthetic dye molecules, thereby demanding effective and innovative remediation strategies. Herein, the potential of novel, thermostable cellulases from Myceliophthora thermophila for the production of cellulose nanofibers (CNFs), a high-value biomaterial using sugarcane bagasse, is presented for the first time. The average diameter of CNFs was calculated to be 20.77 ± 1.11 nm. The CNFs were a stable suspension as indicated by the zeta potential value of − 27.2 mV. The obtained CNFs exhibited a thermal degradation onset temperature of ∼ 205 °C and a crystallinity degree value of ∼ 50.78%. The CNF film demonstrated high tensile strength and BET-specific surface area of 134.603 MPa and 7.5816 m² g⁻¹, respectively. The CNFs were successfully demonstrated as a nanoadsorbent for Congo red (CR) dye adsorption from the aqueous solution with a maximum removal percentage of 95.98% at nanoadsorbent dose = 175 mg, initial dye concentration = 116.54 mg L⁻¹, pH = 3, contact time = 35 min and temperature = 29 °C using central composite design in response surface methodology. The adsorption equilibrium data was found to fit best with the Langmuir isotherm model. The maximum monolayer adsorption capacity was calculated to be 80.84 mg g⁻¹ which was in good agreement with the experimental value. The adsorption kinetic data was found to be described by a pseudo-second-order kinetics model (R² = 1). The adsorption process was endothermic and spontaneous according to the thermodynamic parameters. Based on our findings, the proposed mechanisms of adsorption include electrostatic interactions between positively charged CNF surface and negatively charged CR dye, hydrogen bonding, chemisorption, and physisorption. The synthesized CNF nanoadsorbent also demonstrated high CR removal efficiency of up to 90.45% and 84.68% in Yamuna River water and textile effluent real water samples. The synthesized CNF nanoadsorbent exhibited more than 90% recyclability during seven consecutive adsorption–desorption cycles. Additionally, the dye-adsorbed CNF nanoadsorbent was also successfully demonstrated as a pH monitoring strip. Hence, the present study represents waste-to-wealth innovation by turning agricultural waste into low-cost, high-value CNFs and reusing dye-adsorbed CNF nanoadsorbent for pH monitoring in various applications. Additionally, the present study also enables the sustainable integration of the production of nanocellulose and biofuels by these thermostable enzymes, which provide significant benefits as compared to conventional separate production methods.