Aim: To investigate physicochemical characteristics and especially genotypic diversity of the main culturable micro-organisms involved in fermentation of sap from Borassus akeassii, a newly identified palm tree from West Africa. Methods and Results: Physicochemical characterization was performed using conventional methods. Identification of micro-organisms included phenotyping and sequencing of: 26S rRNA gene for yeasts, 16S rRNA and gyrB genes for lactic acid bacteria (LAB) and acetic acid bacteria (AAB). Interspecies and intraspecies genotypic diversities of the micro-organisms were screened respectively by amplification of the ITS1-5.8S rDNA-ITS2/16S-23S rDNA ITS regions and repetitive sequence-based PCR (rep-PCR). The physicochemical characteristics of samples were: pH: 3Á48-4Á12, titratable acidity: 1Á67-3Á50 mg KOH g À1 , acetic acid: 0Á16-0Á37%, alcohol content: 0Á30-2Á73%, sugars (degrees Brix): 2Á70-8Á50. Yeast included mainly Saccharomyces cerevisiae and species of the genera Arthroascus, Issatchenkia, Candida, Trichosporon, Hanseniaspora, Kodamaea, Schizosaccharomyces, Trigonopsis and Galactomyces. Lactobacillus plantarum was the predominant LAB species. Three other species of Lactobacillus were also identified as well as isolates of Leuconostoc mesenteroides, Fructobacillus durionis and Streptococcus mitis. Acetic acid bacteria included nine species of the genus Acetobacter with Acetobacter indonesiensis as predominant species. In addition, isolates of Gluconobacter oxydans and Gluconacetobacter saccharivorans were also identified. Intraspecies diversity was observed for some species of micro-organisms including four genotypes for Acet. indonesiensis, three for Candida tropicalis and Lactobacillus fermentum and two each for S. cerevisiae, Trichosporon asahii, Candida pararugosa and Acetobacter tropicalis. Conclusion: fermentation of palm sap from B. akeassii involved multi-yeast-LAB-AAB cultures at genus, species and intraspecies level. Significance and Impact of the Study: First study describing microbiological and physicochemical characteristics of palm wine from B. akeassii. Genotypic diversity of palm wine LAB and AAB not reported before is demonstrated and this constitutes valuable information for better understanding of the fermentation which can be used to improve the product quality and develop added value by-products.

Aim: To quantify and identify the predominant lactic acid bacteria (LAB) in dolo and pito wort processing, and to examine their biodiversity at strain level. Materials and Results:The processing of dolo and pito wort was studied at four production sites in Burkina Faso and Ghana. The succession of dominant micro-organisms, pH and titratable acidity were determined from sorghum malt through mashing and acidification to final wort. In the sorghum malt and during mashing, the LAB counts were 5AE7-7AE5 log CFU g )1 . Similar levels of yeasts and gram-negative, catalase-positive bacteria were observed. These levels decreased to 3AE7-4AE5 log CFU g )1 and £2-3 log CFU g )1 , respectively, at the end of mashing, including a mild heat treatment. During acidification at ambient temperature (30-33°C) lasting for 12-16 h, LAB counts increased to 8AE8-9AE9 log CFU g )1 , pH decreased from 5AE55 ± 0AE12 to 3AE72 ± 0AE24, and the titratable acidity calculated as lactic acid, increased from 0AE13% to 0AE61%. The gram-negative, catalase-positive bacteria and yeasts observed in the malt and during mashing were no longer detected. A total of 556 strains of LAB were isolated and purified. The LAB isolates were characterized and identified by a polyphasic approach based on phenotypic and genotypic methods, such as carbohydrate fermentation patterns using API 50 CHL, intergenic transcribed spacers-polymerase chain reaction ⁄ restriction fragment length polymorphism (ITS-PCR ⁄ RFLP), pulsed-field gel electrophoresis (PFGE) and 16S rRNA gene sequencing. Lactobacillus fermentum was identified as the dominant LAB species in the malt during mashing and during acidification. The other species observed during acidification were Lactobacillus delbrueckii ssp. delbrueckii, Lact. delbrueckii ssp. bulgaricus and Pediococcus acidilactici. These bacteria comprised a minor fraction of the bacterial population and no distinct microbial succession was observed for the LAB. At species level, the LAB profiles were similar for the four production sites; however, a pronounced diversity was observed at strain level. For one site, which had implemented a cleaning procedure between batches only, Lact. fermentum was found. Conclusion: Lact. fermentum was found to be the dominant LAB species throughout the entire process to final dolo and pito wort, including the acidification. Lact. delbrueckii ssp. delbrueckii, Lact. delbrueckii ssp. bulgaricus and P. acidilactici occurred in low numbers. At strain level, a high diversity based on PFGE-RFLP was observed for Lact. fermentum within and between sites.

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Fermented foods play a major role in the diet of people in Africa, where a wide variety of raw materials are fermented. Understanding the microbial populations of these products would help in the design of specific starter cultures to produce standardized and safer foods. In this study, the bacterial diversity of African fermented foods produced from several raw materials (cereals, milk, cassava, honey, palm sap, and locust beans) under different conditions (household, small commercial producers or laboratory) in 8 African countries was analysed by 16S rRNA gene amplicon sequencing during the Workshop “Analysis of the Microbiomes of Naturally Fermented Foods Training Course”. Results show that lactobacilli were less abundant in fermentations performed under laboratory conditions compared to artisanal or commercial fermentations. Excluding the samples produced under laboratory conditions, lactobacilli is one of the dominant groups in all the remaining samples. Genera within the order Lactobacillales dominated dairy, cereal and cassava fermentations. Genera within the order Lactobacillales, and genera Zymomonas and Bacillus were predominant in alcoholic beverages, whereas Bacillus and Lactobacillus were the dominant genera in the locust bean sample. The genus Zymomonas was reported for the first time in dairy, cereal, cassava and locust bean fermentations.

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