Identification of acetic acid bacteria isolated from Tunisian palm sap

Abstract

Date palm sap (Phoenix dactylifera L.), called Lagmi, is a sugary substrate that readily ferments through the activity of native microflora that consists mainly of yeasts, lactic acid bacteria and acetic acid bacteria (AAB). The aim of this work was to perform a preliminary step in the isolation and identification of AAB species from different samples of palm sap collected in Southern Tunisia, in order to use them as a starter in vinegar production. AAB were isolated on GEY agar from the fresh palm sap (day (D) 0) and following spontaneous fermentation at room temperature after 3 (D3) and 7 days (D7). A preliminary phenotypic identification of 18 isolates was made by means of Gram, catalase, oxidase and ethanol oxidation to acetic acid, and then further to CO 2 and H 2 O. Subsequently, genotypic identification was conducted by sequencing the gene coding for 16SrRNA and a phylogenetic analysis was obtained based on 16S rRNA sequences. Isolates were identified as Acetobacter tropicalis (11 strains), Acetobacter pasteurianus (3 strains), Acetobacter senegalensis (1 strain), Acetobacter indonesiensis (1 strain), Acetobacter cerevisiaie (1 strain), and Gluconacetobacter liquefacienes (1 strain). The application of selected strains as pure starter cultures for the production of vinegar from palm sap is under investigation in our laboratory.

The forgotten wine: understanding the ecology and composition of palm wine fermentation

“…Palm species can contribute to the regionality of palm wine characters, which are also attributed into a traditional name. In Burkina Faso and Cote d’Ivoire, palm wine is widely known as Bandji (37,38); Mimbo in Cameroon (20,39); Akpeteshie in Ghana (40); Toddy in India (41); Tuak in Indonesia (12,42); Taberna or Tavern in Mexico (11,43); Ogogoro in Nigeria (44); Lambanog in Philippines (45); Ra in Sri lanka (20); Songkhla in Thailand (24); Lagmi in Tunisia (46).…”

“…The traditional names of palm wine vary across the world. In Burkina Faso and Cote d'Ivoire, palm wine is widely known as Bandji (Karamoko et al, 2012;Ouoba et al, 2012); Mimbo in Cameroon (Ciani et al, 2012;Jespersen, 2003); Akpeteshie in Ghana (Amoa-Awua et al, 2007); Toddy in India (Tamang, 2022); Tuak in Indonesia (Hermansyah et al, 2015;Wijaya et al, 2024); Taberna or Tavern in Mexico (Coutiño et al, 2020;Santiago-Urbina & Ruíz-Terán, 2014); Ogogoro in Nigeria (Ikeh et al, 2021); Tuba in Philippines (Gregorio, 2023); Ra in Sri lanka (Ciani et al, 2012); Songkhla in Thailand (Naknean et al, 2010); Lagmi in Tunisia (Malek et al, 2017).…”