ABSTRACT
AIMS: To identify the dominant micro-organisms involved in the production of gowé, a fermented beverage, and to select the most appropriate species for starter culture development. METHODS AND RESULTS: Samples of sorghum gowé produced twice at three different production sites were taken at different fermentation times. DNA amplification by internal transcribed spacer-polymerase chain reaction of 288 lactic acid bacteria (LAB) isolates and 16S rRNA gene sequencing of selected strains revealed that the dominant LAB responsible for gowé fermentation were Lactobacillus fermentum, Weissella confusa, Lactobacillus mucosae, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella kimchii. DNA from 200 strains of yeasts was amplified and the D1/D2 domain of the 26S rRNA gene was sequenced for selected isolates, revealing that the yeasts species were Kluyveromyces marxianus, Pichia anomala, Candida krusei and Candida tropicalis. CONCLUSIONS: Gowé processing is characterized by a mixed fermentation dominated by Lact. fermentum, W. confusa and Ped. acidilactici for the LAB and by K. marxianus, P. anomala and C. krusei for the yeasts. SIGNIFICANCE AND IMPACT OF THE STUDY: The diversity of the LAB and yeasts identified offers new opportunities for technology upgrading and products development in gowé production. The identified species can be used as possible starter for a controlled fermentation of gowé.
Subject(s)
Beverages/microbiology , Gram-Positive Bacteria/isolation & purification , Sorghum/microbiology , Yeasts/isolation & purification , Benin , Candida/genetics , Candida/isolation & purification , Colony Count, Microbial/methods , DNA, Bacterial/genetics , DNA, Fungal/genetics , DNA, Intergenic/genetics , Fermentation , Gram-Positive Bacteria/genetics , Hydrogen-Ion Concentration , Kluyveromyces/genetics , Kluyveromyces/isolation & purification , Lactic Acid/analysis , Lactobacillus/genetics , Lactobacillus/isolation & purification , Pediococcus/genetics , Pediococcus/isolation & purification , Pichia/genetics , Pichia/isolation & purification , Polymerase Chain Reaction/methods , Polymorphism, Restriction Fragment Length/genetics , Yeasts/geneticsABSTRACT
Lactic acid bacteria increased from 3.2 × 10(6) and 1.6 × 10(7) c.f.u./g (wet wt) to 2 × 10(9) and 1.6 × 10(9) c.f.u./g after 12 to 24 h of fermentation of home-produced mawè (a dough produced from dehulled maize) and commercial mawè, respectively. In commercial mawè, the yeast count increased from 1.3 × 10(5) to 2.5 × 10(7) c.f.u./g after 48 h of fermentation before decreasing, whereas in the home-produced mawè it increased from 2.5 × 10(4) to 3.2 × 10(7) c.f.u./g after 72 h of fermentation; the dominant yeasts were mainly Candida krusei, although C. kefyr, C. glabrata and Saccharomyces cerevisiae were also present. Enterobacteriaceae counts increased slightly during the initial stage ofthe fermentation, but decreased below the detection level after 24 to 48 h. Enterobacter cloacae was mostly found in commercial mawè and Escherichia coli mostly in homeproduced mawè.
ABSTRACT
Lactic acid bacteria involved in the natural fermentation of both home-produced and commercial mawè were investigated during a 72 h fermentation period. Lactobacillus spp. constitute the majority (94%) of the strains of the lactic acid bacteria isolated, among which 89% represent the Betabacterium group. They include L. fermentum (biotype cellobiosus) (41%), L. fermentum or L. reuteri (19%), L. brevis (26%), L. confusus (less than 2%), L. curvatus (less than 1%) and L. buchneri (less than 1%). Other isolated lactic acid bacteria were L. salivarius, Lactococcus lactis, Pediococcus pentosaceus, Pediococcus acidilactici and Leuconostoc mesenteroides. Several species were detected at the early stage of fermentation, but the final stage was dominated by L. fermentum (biotype cellobiosus) and L. fermentum or L. reuteri totalling 90% of the isolated strains. The trend was the same for both home-produced and commercial mawè. No strains of L. plantarum, generally reported as dominating lactic acid bacteria at the final stage of fermentation of most plant foods, were isolated.
