# Integrating enzymatic hydrolysis and nanoparticle catalysis for sustainable bioethanol production from pumpkin and dragon fruit pomace by non-conventional yeasts based fermentation prosesses

## TL;DR

This study explores using pumpkin and dragon fruit waste with special yeasts and nanoparticles to produce more bioethanol efficiently.

## Contribution

The integration of nanoparticle-assisted hydrolysis and fermentation significantly boosts bioethanol yield from agricultural waste.

## Key findings

- Pumpkin pomace at 150 g/L produced the highest ethanol concentrations.
- NiO nanoparticles increased ethanol concentration by 95.8% when added to pumpkin pomace.
- Optimized enzymatic hydrolysis and nanoparticle use improved fermentation efficiency.

## Abstract

This study investigated the effects of metal oxide nanoparticles on bioethanol production from lignocellulosic wastes—dragon fruit pomace, and pumpkin pomace—using yeast strains Saccharomyces cerevisiae, Kluyveromyces marxianus, and Candida boidinii. Among the tested substrates, pumpkin pomace yielded the highest ethanol concentrations, particularly at the highest biomass loading (150 g/L). Enzymatic hydrolysis with cellulase was optimized, with 60 FPU/g substrate identified as the most cost-effective loading for maximizing sugar release and ethanol yield. The application of metal oxide nanoparticles (ZnO, Fe2O3, and NiO) was explored to enhance fermentation efficiency. NiO nanoparticles at 20 mg/100 mL significantly improved bioethanol production. Without supplementation, 21.93 g/L of bioethanol (YP/S max: 0.24 g/g, Qp max: 0.18 g/L.h) was obtained from 150 g/L PP. However, when 20 mg/100 mL NiO nanoparticles were added to a 150 g/L pumpkin pomace medium, and the enzyme loading was adjusted to 60 FPU/g substrate, the ethanol concentration increased by 95.8% to 42.64 g/L. YP/S max and Qp max were found to be 0.40 g/g and 0.89 g/L.h, respectively, in these conditions. These results demonstrate that integrating nanoparticle-assisted hydrolysis and fermentation is an effective, cost-saving approach to enhance bioethanol production from low-value agricultural residues, providing a promising approach for sustainable biofuel generation.