Identification of Bacillus species occurring in Kantong, an acid fermented seed condiment produced in Ghana

Abstract

Kantong is a condiment produced in Ghana by the spontaneous fermentation of kapok tree (Ceiba pentandra) seeds with cassava flour as an additive. Fermentation is over a 48h period followed by a drying and a kneading process. Although lactic acid bacteria (LAB) have previously been identified other micro-organisms may also be involved in the fermentation process. In this study we examined the occurrence of aerobic endospore-forming bacteria (AEB) in raw materials, during fermentation and in the final product at 2 production sites in Northern Ghana. Total aerobic mesophilic bacterial counts increased from 5.4±0.1log10CFU/g in the raw materials to 8.9±0.1log10CFU/g in the final products, with the AEB accounting for between 23% and 80% of the total aerobic mesophilic (TAM) counts. A total of 196 AEB were identified at a species/subspecies level by the use of phenotypic tests and genotypic methods including M13-PCR typing, 16S rRNA and gyrA gene sequencing. Bacillus subtilis subsp. subtilis (63% of the AEB), Bacillus safensis (26% of the AEB) and Bacillus amyloliquefaciens subsp. plantarum/Bacillus methylotrophicus (9% of the AEB) were the predominant Bacillus species during fermentation and in the final products. B. amyloliquefaciens/B. methylotrophicus originated from cassava flour, B. safensis from seeds and cassava flour, while the origin of B. subtilis was less clear. Brevibacillus agri and Peanibacillus spp. occurred sporadically. Further investigations are required to elucidate the role of AEB occurring in high numbers, in the fermentation of Kantong.