Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas (ICB), Universidade Federal de Minas Gerais (UFMG), Campus Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
EBTT - Informática, Instituto Federal do Amazonas (IFAM), São Gabriel da Cachoeira, Brazil.
Int Microbiol. 2024 Jun;27(3):807-818. doi: 10.1007/s10123-023-00431-4. Epub 2023 Sep 28.
The present study compared bacterial and fungal diversity of kefir beverages produced using milk (MK) or sugared water (WK) as propagation matrices and grains from the cities of Curitiba (CU) or Salvador (SA), Brazil, by sequencing the complete set of RNA transcripts produced in four products. In Brazil, milk and sugared water are used as matrices to propagate kefir grains. In all beverages, the bacterial community was composed of Lactobacillaceae and Acetobacteraceae. Saccharomycetaceae was the yeast family more abundant in WK, and Dipodascaceae and Pichiaceae in MK. Regarding KEGG mapping of functional orthologs, the four kefir samples shared 70% of KO entries of yeast genes but only 36% of bacterial genes. Concerning main metabolic processes, the relative abundance of transcripts associated with metabolism (energy metabolism) and environmental information processing (membrane transport) had the highest water/milk kefir ratio observed in Firmicutes. In contrast, transcripts associated with genetic information processing (protein translation, folding, sorting, and degradation) oppositely had the lowest water/milk ratios. Concluding, milk and water kefir have quite different communities of microorganisms. Still, the main mapped functional processes are similar, with only quantitative variation in membrane transport and energy acquisition in the water kefir and protein synthesis and turnover in the milk kefir.
本研究比较了使用牛奶（MK）或糖水（WK）作为繁殖基质以及来自巴西库里提巴（CU）或萨尔瓦多（SA）城市的谷物生产的克菲尔饮料的细菌和真菌多样性，通过对四个产品中产生的整套 RNA 转录本进行测序。在巴西，牛奶和糖水被用作繁殖克菲尔颗粒的基质。在所有饮料中，细菌群落由乳杆菌科和醋杆菌科组成。WK 中 Saccharomycetaceae 是最丰富的酵母科，而 MK 中则是 Dipodascaceae 和 Pichiaceae。关于功能直系同源物的 KEGG 映射，四个克菲尔样品共享 70%的酵母基因 KO 条目，但只有 36%的细菌基因。关于主要代谢过程，与代谢（能量代谢）和环境信息处理（膜转运）相关的转录物的相对丰度在厚壁菌门中观察到水/奶克菲尔比例最高。相比之下，与遗传信息处理（蛋白质翻译、折叠、分类和降解）相关的转录物的水/奶比例最低。总之，牛奶和水克菲尔具有非常不同的微生物群落。尽管如此，主要映射的功能过程是相似的，只有水克菲尔中的膜转运和能量获取以及牛奶克菲尔中的蛋白质合成和周转存在定量变化。
