Electrospun Cellulase Nanofibers for Continuous Hydrolysis of Bermuda Grass for Biofuels

Abstract

The increasing demand for stable biocatalysts in lignocellulose hydrolysis highlights the potential of onsite-produced fungal enzyme cocktails. Immobilization of these enzymes can improve their stability, enable reusability, and reduce costs, making them a viable option for sustainable industrial processes. The present study explored the direct encapsulation of the partially purified cellulase obtained from Trichoderma harzianum BPGF1 with polyvinyl alcohol (PVA) into nanofibers through electrospinning. The optimized solution composition for membrane synthesis was determined to be 13% (w/v) PVA and 25% (v/v) of the enzyme. The scanning electron microscopy confirmed the encapsulated enzymes in the nanofiber. The wettability of the electrospun enzyme nanofiber (ENF) was found to be 37.78°, which indicates the hydrophilicity. Young’s modulus of ENF was found to be 28.39 MPa, indicating reliable tensile strength. The effects of pH and temperature were studied on the ENF, and the maximum enzyme activity was observed at pH 7.0 and 70 °C, respectively, when compared with the free enzyme. The kinetic parameters were determined using Michaelis–Menten kinetics. The ENF was tested in the hydrolysis of pretreated Cynodon dactylon grass into fermentable sugars to produce biofuels. The ENF retained 50% of its initial enzyme activity even after 20 cycles, promising its application in continuous hydrolysis.