Isolation and screening of microorganisms from a gari fermentation process for starter culture development

Cassava (Manihot esculenta Crantz), is used for the production of a variety of West African foods and ranks fourth in the list of major crops in developing countries after rice, wheat and maize. Gari is one of the most popular foods produced from cassava. Cassava may contain high levels of linamarin, a cyanogenic glucoside, which in its natural state is toxic to man. Therefore, some processing methods that can enhance the  detoxification of cassava and lead to the improvement of the quality and hygienic safety of the food are vitally important for less toxic products to be obtained. Quality, safety and acceptability of traditional fermented  foods may be improved through the use of starter cultures. There has been a trend recently to isolate wild-type strains from traditional products for use as starter cultures in food fermentation. A total of 74 bacterial strains and 21 yeast strains were isolated from a cassava mash fermentation process in a rural village in Benin, West Africa. These strains were assessed, together with 26 strains isolated at the Council for Scientific and  Industrial Research (CSIR) from cassava samples sent from Benin previously, for phenotypic and  technological properties. 24 presumptive lactic acid bacteria (LAB) were selected for further phenotypic,  genotypic and technological characterization.Key words: Lactic acid bacteria, gari, cassava, fermentation

Streptococcus rubneri sp. nov., isolated from the human throat

Novel, Gram-positive, ovoid lactic acid bacterial isolates LMG 27205, LMG 27206, LMG 27207T and MRI-F 18 were obtained from throat samples of healthy humans. 16S rRNA gene sequence analyses indicated that these isolates belong to the genus Streptococcus, specifically the Streptococcus mitis group, with Streptococcus australis and Streptococcus mitis as nearest neighbours (99.45% and 98.56% 16S rRNA gene sequence similarity, respectively). Genotypic fingerprinting by AFLP and PFGE, DNA-DNA hybridisations, comparative sequence analysis of pheS, rpoA, atpA and physiological and biochemical tests revealed that these bacteria formed a taxon well-separated from its nearest neighbours and other established Streptococcus species and therefore represent a new species, for which the name Streptococcus rubneri sp. nov. is proposed (with LMG 27207T = DSM 26920T) as type strain

Halomonas nigrificans sp. nov., isolated from cheese

A Gram-stain-negative, rod-shaped Proteobacteria isolate, MBT G8648(T), was obtained from an acid curd cheese called Quargel. The isolate was moderately salt tolerant and motile, with numerous peritrichous flagella. The 16S rRNA gene sequence analysis indicated that the strain belongs to the genus Halomonas, with 98.42% 16S rRNA gene sequence similarity with Halomonas titanicae BH1(T) as nearest related neighbour. Further comparative sequence analysis of secA and gyrB genes, as well as physiological and biochemical tests, revealed that this bacterium formed a taxon well-separated from its nearest neighbours and other established Halomonas species. Thus, the strain represents a new species, for which the name Halomonas nigrificans sp. nov. is proposed, with strain MBT G8648(T) (= LMG 29097(T) = DSM 105749(T)) as type strain

Scripture and reform

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