Improved bioethanol production from cocoa agro-industrial waste optimization based on reaction rate rules

BACKGROUND

Bioethanol production was enhanced from cocoa agro-industrial wastes by optimizing the reaction rate. A lab-scale set-up allowed us to show the proof of concept, in which agro-industrial wastes were fermented by Candida krusei. The goal was to show how a simple equation, based on Euler–Lagrange theory, has a feedback structure to command online from the measured variables related to cell growth and metabolism. The online correction involved computation of the feeding rate F_in from the derived equation.

RESULTS

The proposed improvement resulted in increased bioethanol production. Bioethanol production from exponential and pulse strategies was 61 and 75 g L⁻¹, respectively, but reached 85 g L⁻¹ with the proposed improvement. The initial glucose concentration for the proof of concept was 60 g L⁻¹. The results show that the proposed optimization enhanced bioethanol production by about 24% and 36% with respect to exponential and pulse strategies, respectively. Thus, the Euler–Lagrange theory improves bioethanol production through F_in by optimizing the reaction rate with a very simple real-time implementation.

CONCLUSION

This contribution provides a solid basis for potential industrial implementation with only the inflow profile as the unique measured variable to produce bioethanol as fuel from agro-industrial wastes. Thus, the proposed optimization might provide long-term benefits for economical bioethanol production via industrial ecology in terms of a carbon-neutral circular economy. © 2025 Society of Chemical Industry (SCI).