Fagbemigun Olakunle, Cho Gyu-Sung, Rösch Niels, Brinks Erik, Schrader Katrin, Bockelmann Wilhelm, Oguntoyinbo Folarin A, Franz Charles M A P
Department of Microbiology, Faculty of Science, University of Lagos, Akoka, 100213 Lagos, Nigeria.
Department of Microbiology and Biotechnology, Max Rubner-Institut, Hermann-Weigmann-Straße 1, 24103 Kiel, Germany.
Microorganisms. 2021 Mar 19;9(3):640. doi: 10.3390/microorganisms9030640.
, an important traditional fermented dairy food produced from cow's milk in Nigeria, was studied for microbial diversity and for starter culture development for industrial production. On the basis of a polyphasic approach, including phenotypic and genotypic methods such as 16S rRNA gene sequencing, repetitive element PCR (rep-PCR) fingerprinting metagenomics, and whole genome sequencing, we identified () , , , and () as predominant bacterial species involved with milk fermentation during traditional production in Nigeria, while the predominant yeast species in was identified as . Using metagenomics, and potential pathogens such as enterobacteria were detected at low levels of abundance. Strains of the predominant lactic acid bacteria (LAB) were selected for starter cultures combination on the basis of their capacities for rapid growth in milk and reduction of pH below 4.5 and their gelling characteristic, which was demonstrated noticeably only by the strains. Whole genome sequence analysis of selected bacterial strains showed the largest assembled genome size to be 2,169,635 bp in 314, while the smallest genome size was 1,785,639 bp in 328M. Genes encoding bacteriocins were not detected in all the strains, but all the LAB possessed genes potentially involved in diacetyl production and citrate metabolism. These bacteria isolated from can thus be used to improve the microbial safety quality of in Nigeria, in addition to improving technological parameters such as gelling viscosity, palatability, and product consistency.
在尼日利亚,一种由牛奶制成的重要传统发酵乳制品被用于研究微生物多样性以及开发用于工业生产的发酵剂培养物。基于多相方法,包括表型和基因型方法,如16S rRNA基因测序、重复元件PCR(rep-PCR)指纹图谱宏基因组学和全基因组测序,我们鉴定出在尼日利亚传统生产过程中参与牛奶发酵的主要细菌种类为()、、、和(),而中主要的酵母种类被鉴定为。使用宏基因组学,检测到了和诸如肠杆菌等潜在病原体,但其丰度较低。基于主要乳酸菌(LAB)菌株在牛奶中快速生长以及将pH值降低至4.5以下的能力及其凝胶化特性(仅菌株表现明显),选择这些菌株用于发酵剂培养物组合。对选定细菌菌株的全基因组序列分析表明,组装的最大基因组大小在314中为2,169,635 bp,而最小基因组大小在328M中为1,785,639 bp。并非在所有菌株中都检测到编码细菌素的基因,但所有LAB都拥有可能参与双乙酰生产和柠檬酸盐代谢的基因。因此,从分离出的这些细菌除了可改善诸如凝胶粘度、适口性和产品一致性等技术参数外,还可用于提高尼日利亚的微生物安全质量。