African Journal of Biotechnology Vol. 4 (7), pp. 646-656, July 2005          
ISSN 1684–5315 © 2005 Academic Journals

Full Length Research Paper

Identification and typing of the yeast strains isolated from bili bili, a traditional sorghum beer of Chad

Nanadoum MAOURA¹*, Mbailao MBAIGUINAM¹ Huu Vang NGUYEN², Claude GAILLARDIN² and Jacques POURQUIE².

¹Laboratoire de Recherche sur les Substances Naturelles - Faculté des Sciences Exactes et Appliquées BP 1027 N’djaména Tchad 

²Laboratoire de Microbiologie et de Génétique Moléculaire. INA-PG INRA  CBAI BP 01, 78 850 Thiverval Grignon France.

*Corresponding author.E-Mail: nanadoum@yahoo.com. Fax: 00 (235) 51 40 33. Phone: (235) 27 11 38.

Accepted 14 April 2005

Seventy six yeast strains isolated form bili bili and others sample were identified and typed in purpose of selecting appropriate starter culture. Identification techniques included conventional phenetic method, PCR/RFLP of NTS2 rDNA region, partial sequencing of the D1/D2 region of 26S rDNA and karyotyping using contour clamped homogenous electric field (CHEF) technique. The Saccharomyces cereviseiae strains were also compared to industrial strains according to their fermentation profiles on maltose in the presence of 2-deoxy-D-glucose and to their karyotypes. We observed that the fermentation of bili bili was carried out by an indigenous natural flora predominantly represented by highly polymorphic S. cerevisiae strains whereas early steps in the process were carried out mainly  by Kluyveromyces maxianus strains. All of the S. cerevisiae strains which were used in trial fermentation gave a good rate of fermentation suggesting that they may be used as starter cultures.

Key words: Sorghum beer, bili bili, yeast flora, Saccharomyces cerevisiae, Kluyveromyces marxianus, PCR/RFLP of the NTS2-rDNA; karyotyping, fermentation.