Evaluation of the Bioethanol Potential of Nauclea Latifolia (Sm.) Fruit Juice

Abstract

Commonly called African peach tree, the Nauclea latifolia (Sm.) of Rubiaceae family gives fruits twice a year. It is also a well known plant in sub-Saharan Africa in the traditional pharmacopoeia. The fruits of the African peach tree are one of the countless fruits of this continent which, in lethal period, are left in the nature where they rot, thus causing a big shortage to the farmers of our country and those of the sub-region West Africa. This is why the objective of this study is to promote the fruits of Nauclea latifolia (Sm.) through the bioconversion of their juice by fermentation into ethanol as biofuel. For this, different initial concentrations (1, 2, 3, 4 and 5g/l) of Saccharomyces carlsbergensis and three strains of Saccharomyces cerevisiae reference were used on the juice formulated to the proportion of 1.5L of distilled water per kilogram (1kg) of fruit. The monitoring of the parameters (pH, density and brix degree) of 4g/l urea-enriched juices, not only enriched revealed the performance of Saccharomyces carlsbergensis and Saccharomyces cerevisiae strains in the alcoholic fermentation of the Nauclea latifolia (Sm.) fruit juice. From this work, it appears that the best efficiencies of bioethanol productivity of 122.4±0.4, 119.4±0.3 and 119.2±0.2ml/kg of fruit were obtained respectively from the enriched mashes with Thermal-tolerant alcohol (2 and 3g/l) and non-enriched must to Angel super alcohol (2g/l). This study shows that Saccharomyces cerevisiae's Thermal-tolerant alcohol and Angel super alcohol are more effective in the fermentation of Nauclea latifolia (Sm.) fruit juice into bioethanol.