Cashew tree is produced today mainly for its nut; the apple to which the nut is attached is neglected despite its richness in secondary metabolites and isn't consumed because of its astringency due to tannins presence. Indeed, its richness in fermentable sugars and in mineral elements and vitamins, makes it a substrate of choice in agro-resources bioconversion into bioethanol by fermentation. The present study aims to convert cashew apples residues into bioethanol by fermentative way in the presence of the yeasts: Saccharomyces carlsbergensis and Saccharomyces cerevisiae. The pressing residues of the cashew apples collected in the Center of Benin underwent an enzymatic hydrolysis. Monitoring the release of sugars, phenolic compounds and the Brix degree, as well as some optimization parameters, made it possible to better assess the efficiency of the processes. From results obtained, the hydrolyzate A1 presented a high content of total sugars (28.84g/L) and a high alcohol degree of (28.28 ± 1.03%) for a first distillation after fermentation. The best performance in ethanolic bioconversion was recorded in the presence of Saccharomyces carlsbergensis yeast. These investigations made it possible to highlight the potential use of these agro-industrial residues to produce bioethanol fuel.

Nutritional requirements in the fermentation process are key parameters for optimal yeast development and ethanol production. Natural nutritional supplements rich in nitrogen, phosphorus, sulfur, and micro-elements can improve the performance of yeasts and offer a sustainable, cost-effective, and environmentally friendly alternative to synthetic chemicals. This study aimed at investigating the effect of a natural yeast nutrient (fermented Parkia biglobosa seeds) on bioethanol production from cashew apple juice by Saccharomyces cerevisiae. The proximate and mineral compositions of fermented seeds were evaluated. Their powder was added to yeast medium at a concentration of 4–12 g/L. The behavior of two yeast strains (Angel brand super alcohol (S1) and Angel brand thermal-tolerant alcohol (S2)) was inspected. Titratable acidity, pH, °Brix, and density were evaluated during 144 h of fermentation. Sugar consumption was maximal after 72 and 48 h of fermentation for S1 and S2 yeast strains, respectively. The best ethanol yields of 0.19 and 0.22 g/g were obtained with S1 and S2 yeast strains, respectively, using 12 g/L of nutrients for the first and without nutrient supplementation for the second (control sample). The non-conventional nutrients from fermented P. biglobosa seeds seem to be favorablefor ethanol production using only S1 yeast strain.

Water, potential source of life, must undergo various physico-chemical and bacteriological analyzes that will define its quality for human consumption in order to avoid the risk of water-borne diseases to consumers. Physico-chemical and bacteriological quality of an Ouega-Fandji's drilling water, use as drinking water, were investigated. Two (02) samples are constituted for the two analyzes' types. Twenty physico-chemical parameters (