Optimization Of Ph, Time, Yeast Substrate Ratio And Temperature For Production Of Bioethanol From Sweet Potato (Ipomoea Batatas) Peels
Date
2025Author
Opiyo, Sylvia Awino
Osewe, Elly Tetty
Vitalis, Osumba Onyango
Metadata
Show full item recordAbstract
Introduction: The growing demand for renewable energy has led to increased interest in bioethanol production
from non-food biomass. Sweet potato (Ipomoea batatas) peels, an agro-industrial waste, present a viable
feedstock for bioethanol production using Saccharomyces cerevisiae. This study aimed to optimize fermentation
conditions, specifically pH, temperature, fermentation time, and yeast-substrate ratio, to maximize bioethanol
yield.
Methodology: Sweet potato peels were collected, dried, and then hydrolyzed using 0.5M, 1.0M, 1.5M and
2.0MHCl to release fermentable sugars. The fermentation process was carried out using Saccharomyces
cerevisiae, with pH levels adjusted to 4.5, 5.0, 5.5, and 6.0. The effect of different fermentation conditions on
bioethanol yield was assessed. ANOVA was used to determine the significance of independent factors and their
interactions, and a regression model was developed to predict bioethanol yield.
Results: The optimized conditions for bioethanol production were temperature: 30°C, pH: 7.0, fermentation time:
72 minutes, and yeast amount: 0.35 g/50mL, yielding 0.0655 mol of bioethanol. ANOVA results indicated that pH
and yeast amount significantly influenced bioethanol yield independently, while temperature and time were only
significant in interaction with other factors. The quadratic effect of pH was strong, suggesting an optimal range
for bioethanol production. The interaction of temperature with pH and temperature with yeast amount
significantly influenced bioethanol yield. The regression model demonstrated high accuracy (R² = 99.42%) in
predicting bioethanol production.
Conclusion and Recommendations: pH and yeast amount have a significant independent effect on bioethanol
yield, while temperature and time are only significant when considered in interaction with other factors.
Quadratic effects show that pH has a strong curvature, suggesting an optimal range for bioethanol production,
while time has a borderline effect. Interaction analysis reveals that temperature combined with pH, as well as
temperature combined with yeast amount, significantly influence bioethanol yield. The study recommends that
the optimized parameters should be tested at a pilot scale before full-scale implementation so as to assess
feasibility for bioethanol production from sweet potato peels.
Collections
- Journal Articles (PAS) [301]
