Aims: To examine isolates of Bacillus subtilis and B. pumilus predominant in Soumbala for their ability to degrade African locust bean proteins (ALBP). Methods and Results: Agar diffusion test in casein and ALBP agar was used for screening of isolates. The profiles of water-soluble proteins and free amino acids (FAA) during the fermentation of ALBP by the Bacillus isolates were studied by SDS-PAGE and cation exchange chromatography. The profile of soluble proteins changed with the fermentation time and varied depending on the isolate. The quantity of total FAA and essential FAA such as lysine was increased sharply between 24 and 48 h of fermentation and differed among the isolates. Simultaneously, a pH increase was observed. Cysteine, methionine, leucine, isoleucine, tyrosine and phenylalaline appeared during fermentation. Conclusion: The Bacillus isolates studied degraded ALBP leading to a profile of soluble proteins and FAA specific for each isolate. Significance and Impact of the Study: This study contributes to the selection of Bacillus strains to be used as starter cultures for controlled production of Soumbala.

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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.

Aims: To investigate predominant isolates of Bacillus subtilis and B. pumilus in soumbala, a fermented African locust bean condiment, for their ability to degrade African locust bean oil (ALBO). Methods and Results: Agar diffusion test in tributyrin and ALBO agar was used for screening of the isolates for esterase and lipase activity, respectively. The quantity and the profile of free fatty acids (FFA) during 72 h of degradation of ALBO by the Bacillus isolates were studied by titration and gas chromatography. The degradation of tributyrin and ALBO was variable among the isolates. Two strains of B. subtilis and two strains of B. pumilus showed significantly higher esterase and lipolytic activities than the others. The degradation ALBO was most pronounced in enriched nutrient agar except for one isolate of B. pumilus degrading ALBO to the same extent regardless of the enrichment. The quantity of FFA released from ALBO by the most lipolytic strains of Bacillus increased mainly between 0 and 24 h and differed among the isolates. The profile of FFA was similar for the Bacillus isolates with oleic acid (C18:2) occurring as the major FFA in all the samples except in samples incubated with B. subtilis B9 where stearic acid (C18) was dominant. Conclusion: Bacillus isolates from soumbala showed high strain dependent lipolytic activity against ALBO. Significance and Impact of the Study: This study contributes to the selection of Bacillus strains to be used as starter cultures for controlled production of soumbala.

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