Abstract: The biotransformation of four naturally occurring acetylenic thiophenes; 5-(3-buten-l-nyl)-2, 2¹-bithienyl (I), alpha-terthienyl (II); 5-(4-acetoxy-1-butinyl)-2, 2¹-bithienyl (III); and 5-(4-hydroxy-1-butinyl)-2, 2¹-bithienyl (IV) isolated from the root of Tagetes Patula nana (African marigold) by the microflora in fermenting cassava substrate was investigated. One of the thiophenes, 5-(4-acetoxy-1-butinyl)-2, 2¹-bithienyl (III) was successfully hydrolised after 7 days of fermentation.