The marula and elephant intoxication myth: assessing the biodiversity of fermenting yeasts associated with marula fruits (Sclerocarya birrea)

Abstract

The inebriation of wild African ele phants fr om eating the ripened and rotting fruit of the marula tree is a persistent myth in Southern Africa. How ever, the y easts r esponsib le for alcoholic fermentation to intoxicate the elephants remain poorly documented. In this study, we consider ed Botsw ana, a countr y with the world's largest population of wild elephants, and where the marula tree is indigenous, a bundant and pr otected, to assess the occurr ence and biodi v ersity of yeasts with a potential to ferment and subsequently inebriate the wild elephants. We collected marula fruits from over a stretch of 800 km in Botswana and isolated 106 yeast strains r e pr esenting 24 yeast species. Over 93% of these isolates, typically known to ferment simple sugars and produce ethanol comprising of high ethanol producers belonging to Sacchar om yces , Br ettanom yces , and Pichia, and intermediate ethanol producers Wickerhamom yces , Zygotorulaspora, Candida, Hanseniaspora , and Kluyver om yces . Fermentation of marula juice r ev ealed convincing fermentati v e and ar omatic bouquet credentials to suggest the potential to influence foraging behaviour and inebriate elephants in nature. There is insufficient evidence to refute the aforementioned myth. This work serves as the first work to war ds understanding the biodi v ersity marula associated yeasts to debunk the myth or appr ov e the facts.