Characterization of Saccharomyces cerevisiae Strains from Palm Wine for Baking Leaven Production in Republic of Congo

Abstract

This study was carried out to select the autochthon yeast strains from the palm wine. The work aims to wildly isolate, characterize and identify Saccharomyces cerevisiae in order to locally and safely produce a bio-leaven and to assess their ability to ferment wheat flour dough used for the bread making and other products. Palm wine samples have been bought in the village around Brazzaville. Samples have been collected in sterile glass bottles then stored under refrigeration condition at 4°C until they were processed. Yeasts were enumerated and isolated on Dichloran Rose Bengal Chloramphenicol agar medium at 37°C. Molecular identification was carried out by a PCR-based method using species-specific primer pairs to Saccharomyces genus without sequencing stage. The results showed that palm wine contains about 3.3106 CFUmL-1. Fifty-one isolates were obtained with a percentage of 13% corresponding to Saccharomyces cerevisiae. This identity was confirmed by the molecular characterization. Five yeast strains showed high ability to ferment wheat flour dough analogous of the control. The better growth of isolates was between 28 and 37°C. However, the near neutral pH gives the higher growth. High concentration of NaCl and glucose in medium has a strong negative impact on the growth of isolates.