Food Microbiology and Mushroom Research Division, CSIR-Food Research Institute, Accra, Ghana.
Department of Nutrition and Food Science, University of Ghana, Accra, Ghana.
BMC Microbiol. 2024 May 14;24(1):163. doi: 10.1186/s12866-024-03317-1.
Spontaneous fermentation of cereals like millet involves a diverse population of microbes from various sources, including raw materials, processing equipment, fermenting receptacles, and the environment. Here, we present data on the predominant microbial species and their succession at each stage of the Hausa koko production process from five regions of Ghana. The isolates were enumerated using selective media, purified, and phenotypically characterised. The LAB isolates were further characterised by 16S rRNA Sanger sequencing, typed using (GTG) repetitive-PCR, and whole genome sequencing, while 28S rRNA Sanger sequencing was performed for yeast identification. The pH of the millet grains ranged from mean values of 6.02-6.53 to 3.51-3.99 in the final product, depending on the processors. The mean LAB and yeast counts increased during fermentation then fell to final counts of log 2.77-3.95 CFU/g for LAB and log 2.10-2.98 CFU/g for yeast in Hausa koko samples. At the various processing stages, the counts of LAB and yeast revealed significant variations (p < 0.0001). The species of LAB identified in this study were Limosilactobacillus pontis, Pediococcus acidilactici, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Pediococcus pentosaceus, Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Schleiferilactobacillus harbinensis, and Weissella confusa. The yeasts were Saccharomyces cf. cerevisiae/paradoxus, Saccharomyces cerevisiae, Pichia kudriavzevii, Clavispora lusitaniae and Candida tropicalis. The identification and sequencing of these novel isolates and how they change during the fermentation process will pave the way for future controlled fermentation, safer starter cultures, and identifying optimal stages for starter culture addition or nutritional interventions. These LAB and yeast species are linked to many indigenous African fermented foods, potentially acting as probiotics in some cases. This result serves as the basis for further studies into the technological and probiotic potential of these Hausa koko microorganisms.
谷物(如小米)的自然发酵涉及来自不同来源的多种微生物,包括原材料、加工设备、发酵容器和环境。在这里,我们展示了来自加纳五个地区 Hausa koko 生产过程每个阶段的主要微生物种类及其演替的数据。使用选择性培养基对分离物进行计数、纯化和表型表征。使用 16S rRNA Sanger 测序对 LAB 分离物进行进一步表征,使用(GTG)重复-PCR 进行分型,并进行全基因组测序,同时对酵母进行 28S rRNA Sanger 测序。小米谷物的 pH 值范围从加工者的平均值 6.02-6.53 到最终产品的 3.51-3.99。在发酵过程中,LAB 和酵母的平均计数增加,然后下降到 Hausa koko 样品中 LAB 的最终计数为 log 2.77-3.95 CFU/g 和酵母的最终计数为 log 2.10-2.98 CFU/g。在各个加工阶段,LAB 和酵母的计数显示出显著差异(p<0.0001)。本研究中鉴定的 LAB 物种为 Limosilactobacillus pontis、Pediococcus acidilactici、Limosilactobacillus fermentum、Limosilactobacillus reuteri、Pediococcus pentosaceus、Lacticaseibacillus paracasei、Lactiplantibacillus plantarum、Schleiferilactobacillus harbinensis 和 Weissella confusa。酵母为 Saccharomyces cf. cerevisiae/paradoxus、Saccharomyces cerevisiae、Pichia kudriavzevii、Clavispora lusitaniae 和 Candida tropicalis。这些新分离物的鉴定和测序以及它们在发酵过程中的变化将为未来的受控发酵、更安全的起始培养物以及确定起始培养物添加或营养干预的最佳阶段铺平道路。这些 LAB 和酵母物种与许多非洲本土发酵食品有关,在某些情况下可能具有益生菌作用。该结果为进一步研究 Hausa koko 微生物的技术和益生菌潜力提供了基础。