Bioethanol, a renewable energy source, holds significant promise for reducing fossil fuel dependence. A recent study explored a hybrid pathway for producing bioethanol using lignocellulosic biomass, specifically empty fruit bunches (EFB) co-gasified with charcoal. This process, optimized using response surface methodology (RSM), presents a novel approach to syngas fermentation and bioethanol production within an integrated biorefinery framework.
The research focused on synthesizing syngas through the co-gasification of EFB and charcoal mixtures in a 75:25 ratio. The optimal ratio of these components was identified via central composite design, a statistical technique that facilitates efficient experimentation. This methodology enabled researchers to fine-tune the gasification process, ensuring maximum syngas yield, which is crucial for subsequent fermentation steps.
Two microorganisms, Saccharomyces cerevisiae and Clostridium butyricum, were employed to ferment the syngas. Their individual performances, along with their co-fermentation capabilities, were evaluated based on colony-forming units (CFU), pH, total organic carbon (TOC), and syngas flow rate. This comprehensive investigation aimed to determine the most effective fermentation strategy for bioethanol production.
Field emission scanning electron microscopy (FESEM) was utilized to characterize the morphological features of the microorganisms during syngas fermentation. This advanced imaging technique provided detailed insights into the structural adaptations of the microbes, which are essential for optimizing fermentation conditions and enhancing bioethanol yields. The morphological analysis revealed distinct differences in microbial structures under various fermentation conditions, indicating the adaptability and resilience of these microorganisms in syngas environments.
The study’s findings revealed that co-fermentation of S. cerevisiae and C. butyricum resulted in the highest bioethanol concentration, reaching 31.20 mmol. This was significantly higher than the yields from single-inoculum fermentations. The results underscored the synergistic benefits of using multiple microorganisms in the fermentation process, as they can utilize different components of the syngas more efficiently. Co-fermentation not only enhanced bioethanol yield but also improved the overall robustness and stability of the fermentation process.
Additionally, increasing the syngas flow rate from 50 mL/min to 1000 mL/min led to a significant improvement in bioethanol productivity, with a 3.08% increase. This highlights the importance of optimizing operational parameters, such as syngas flow rate, to maximize bioethanol production. The study demonstrated that higher flow rates facilitated better gas-liquid mass transfer, enhancing microbial activity and fermentation efficiency.
In conclusion, this study demonstrates that microbial co-fermentation, combined with optimized gasification processes, can significantly enhance bioethanol production from lignocellulosic biomass. By employing a hybrid pathway and leveraging the unique capabilities of different microorganisms, researchers can develop more efficient and sustainable methods for bioethanol production. This innovative approach not only advances the field of biofuel research but also contributes to the broader goal of developing renewable energy sources. The integration of gasification and fermentation processes represents a significant step forward in the pursuit of sustainable and economically viable biofuel production technologies.
Reference
Link: https://doi.org/10.1080/17597269.2024.2371240
Author: Tofan Agung Eka Prasetya, S.Kep., M.KKK., Ph.D.
Hybrid pathway of bio-ethanol production employing empty fruit bunches co-gasified with charcoal and mixed culture fermentation: Optimization using response surface methodology. Biofuels.
