Continuous ethanol production from pineapple cannery waste using immobilized yeast cells

Area of Science:

• Biotechnology and Bioengineering
• Industrial Microbiology
• Renewable Energy

Background:

• Pineapple cannery waste presents a significant lignocellulosic feedstock for bioconversion.
• Efficient ethanol production requires robust microbial systems and optimized reactor configurations.
• Immobilization techniques can enhance microbial performance and process stability.

Purpose of the Study:

• To evaluate the efficacy of immobilized Saccharomyces cerevisiae for ethanol production from pineapple cannery waste.
• To determine optimal operating conditions and assess the long-term performance of an immobilized cell reactor.

Main Methods:

• Immobilization of Saccharomyces cerevisiae ATCC 24553 cells within a k-carrageenan matrix.
• Utilizing a tapered glass column reactor for continuous ethanol fermentation.
• Operating the reactor at controlled temperature (30°C) and pH (4.5) with varying dilution rates.

Main Results:

• Maximum volumetric ethanol productivity reached 42.8 g ethanol L⁻¹ h⁻¹ at a dilution rate of 1.5 h⁻¹.
• Immobilized cells exhibited approximately 11.5 times higher volumetric productivity compared to free cells.
• The reactor maintained stable immobilized cell activity for 87 days at a dilution rate of 1.0 h⁻¹.

Conclusions:

• k-Carrageenan immobilization of Saccharomyces cerevisiae is a highly effective strategy for enhancing ethanol production from pineapple waste.
• The developed immobilized cell reactor demonstrates superior productivity and operational stability, suitable for industrial biofuel applications.
• This approach offers a promising avenue for valorizing food industry by-products into valuable biofuels.