TITLE:
Waste Cashew Apple (Anacardium occidentale) as Feedstock for Simultaneous Production of Two Main Ecofriendly Fuels
AUTHORS:
Delphine N’guessan, Micaël Bedikou, Verdier Abouo, Lamine Samagaci, Charlotte Ehon, Camara Yacouba, Eric Akpa
KEYWORDS:
Cashew Waste Valorization, Bioalcohol Production, Renewable Energy, Isobutanol, Ethanol
JOURNAL NAME:
Journal of Power and Energy Engineering,
Vol.11 No.8,
August
21,
2023
ABSTRACT: The present work investigated an effective low-cost production of
bioethanol by the use of rejected cashew apples (CAs) in
Ivorian plantations. Fresh CAs were
cut into 8-10 mm slices and submitted to a drying cycle of two periods (for the sake
of easing their rehydration) in an oven with forced air convection. Temperature
was first set at 30˚C for 3 hours, and then
raised at 50˚C until constant weight. Drying brought about 82% weight loss, and
the dried slices were rehydrated in a ratio
of 1:4 (w/v) in warm distilled water to reconstitute a 10 Brix degree
(˚B) juice with 1.042 g/cm3 density. The sugar content of the juice was increased to 20˚B (syrup) by
thermal evaporation. The process was optimized using a response surface
methodology (RSM) by applying a central composite plan in order to minimize
heat-sensitive compound degradation. The optimal operating conditions for
temperature and time of heating were precisely 68,239˚C and 83,314 min,
respectively. The commercial baker’s yeast Saccharomyces cerevisiae was used to seed the 20˚B cashew
apple syrup following a batch fermentation at 30˚C. The total alcohol content
recorded after 24 hours was 8.24% ±
0.11% made up of almost 97% of ethanol and isobutanol (a higher alcohol).
Analysis of alcoholic profiles by flam ionization detector-gas chromatography
(GC-FID) showed an ethanol content of 3.92% and an almost similar but higher
quantity of isobutanol (4.05%) with the latter being a by-product. As bio-based
isobutanol attracts more and more attention due to its wide application and
excellent fuel performance as compared to ethanol, it emerged from this study
that neglected cashew apples can be
successfully employed as valuable raw material for the simultaneous production of both biofuels currently used as sustainable sources of
renewable energy.