S22 - Session O2 - The Hunter Shirt: The role of Acacia nilotica in fermentative textile dyeing

Authors: Laurence Douny *, Regine Hengge, José Ignacio Hernandez Lobato, Salif Sawadogo

For centuries, across West Africa, plants have been used extensively not only in traditional medicine but also for dyeing cloth. Examples are the use of the bark of Lannea microcarpa , the root of Cochlopermum tinctoria and the pod of Acacia nilotica , which together form the basis of a complex natural colorant produced by the hunters of the Marka-Dafing community in north-western Burkina Faso. This colorant is used by the hunters to dye their ceremonial donso dileke (hunter shirt). The dye, known as vouwa , is prepared by macerating plants in water containing the earth of a termite mound and minerals. The tinctorial plants then undergo a long process of fermentation, whereby an essential role is played by certain bacteria present in the mud. This paper examines the use of extracts of the pods of A. nilotica to counteract certain unwanted bacteria that under non-optimal conditions may overgrow the dyeing jar by forming thick biofilms. Besides showing some previously studied antibacterial activity, extracts of A. nilotica pods have also been found to interfere efficiently with the biofilm formation of these unwanted bacteria. By suppressing the disruptive bacteria, A. nilotica seems to support the proliferation and desired activity of the bacteria that contribute to the colouring of the textile (mainly anaerobic producers of iron sulfide). While extensive research has been carried out on the phytochemistry of traditional medicinal plants, in this ongoing study, the authors investigate the role of A. nilotica in traditional fermentative cloth dyeing by looking into aspects of the microbiome that develops during the dyeing of the hunter shirt. This interdisciplinary approach to the complex roles of natural dyes combines extensive field research conducted from the perspective of anthropology with science-based research using methods of classical and molecular microbiology.