Valorization of banana frond juice for bioethanol production: Process efficiency and circular economy implications

Abstract

This investigation evaluates the microbial conversion capacity of banana frond juice (BFJ) as an accessible lignocellulosic feedstock through Saccharomyces cerevisiae fermentation under the best possible operation conditions. Mechanical pressing of fresh banana fronds produced juice with a yield average of 0.33 ± 0.02 L/kg along with an initial total sugar content of 76.4 ± 2.8 g/L. The bioconversion of clarified BFJ occurred under batch fermentation conditions at pH 5.6 and 36°C using 10% v/v yeast inoculum for 120 hours while measuring ethanol production together with sugar consumption at 24-hour intervals. The fermentation process achieved total sugar depletion at 96 hours, resulting in an ethanol production of 45.75 ± 1.1 g/L, which delivered a yield of 0.33 g/g sugar and an efficiency of 64.7% compared to theoretical maximums. During the fermentation process, researchers achieved an average volumetric ethanol productivity level of 0.38 g/L·h. The yield results of BFJ fall within competition when compared to sugarcane juice, oil palm frond juice, and banana pseudostem hydrolysates, while also requiring few processing steps without enzymatic or chemical pretreatment (Legodi et al., 2021). Statistical data showed that sugar consumption is directly linked to ethanol production through a correlation level of R² = 0.987 (p < 0.01). Biofuel production benefits from the Flush rejects/consumes BFJ as a promising and inexpensive raw material. The incorporation of banana fruit juice as a sustainable biofuel feedstock becomes viable due to its simple preprocessing demands combined with advantageous fermentation behaviour and circular bioeconomic alignment.