Investigating bacterial population structure and dynamics in traditional koumiss from Inner Mongolia using single molecule real-time sequencing.

Koumiss is considered as a complete dairy product high in nutrients and with medicinal properties. The bacterial communities involved in production of koumiss play a crucial role in the fermentation cycle. To reveal bacterial biodiversity in koumiss and the dynamics of succession in bacterial populations during fermentation, 22 samples were collected from 5 sampling sites and the full length of the 16S ribosomal RNA genes sequenced using single molecule real-time sequencing technology. One hundred forty-eight species were identified from 82 bacterial genera and 8 phyla. These results suggested that the structural difference in the bacterial community could be attributed to geographical location. The most significant difference in bacterial composition occurred in samples from group D compared with other groups. The sampling location of group D was distant from the city and maintained the primitive local nomadic life. The dynamics of succession in bacterial communities showed that Lactobacillus helveticus increased in abundance from 0 to 9h and reached its peak at 9h and then decreased. In contrast, Enterococcus faecalis, Enterococcus durans, and Enterococcus casseliflavus increased gradually throughout the fermentation process, and reached a maximum after 24h.

Assessment of the bacterial and fungal diversity in home-made yoghurts of Xinjiang, China by pyrosequencing.

BACKGROUND: The aim of this study was to gain a deeper knowledge of the bacterial and fungal community diversity in local home-made yoghurts from Zhaosu and Tekesi counties, Xinjiang, China, where a relatively high proportion of the ethnic minority population resides. RESULTS: The bacterial and fungal community diversity in 22 home-made yoghurt samples was analyzed by pyrosequencing. This approach revealed the presence of six bacterial and two fungal phyla, comprising 69 bacterial and 20 fungal genera respectively, among all samples. Firmicutes and Ascomycota were the dominant phyla and Lactobacillus and Saccharomyces the predominant genera of bacteria and fungi respectively. Based on redundancy analysis, the bacterial diversity in samples from the two counties differed mainly because of eight responsive operational taxonomic units of Lactobacillus. However, no obvious difference existed in the fungal population of samples from the two counties. CONCLUSION: The results indicated that the microbial community of home-made yoghurts varied with their geographical origin and manufacturing process. The study showed that pyrosequencing could provide a better understanding of microbiological diversity as well as useful information for future studies on the selection of starter cultures for yoghurts.

Bacterial composition and function during fermentation of Mongolia koumiss.

Koumiss is a fermented mare's milk beverage that has attracted increasing attention due to its nutritional richness and important economic value. Bacteria in koumiss play a major role in pH decreasing and reducing spoilage through bacterial inhibition. The dynamic changes in nutritional content were determined firstly during fermentation, and then the metagenomics sequencing technology was applied to profile koumiss core microbiota at the species level. We also clarified the function and effect of the bacteria on the nutritional content of the final product. We also investigated active microbial function by comparing the metagenomics of representative samples collected at different time points during the fermentation process. This study dynamically revealed the bacterial composition and function of traditional koumiss during its making process. Twenty-three major functional categories related to amino acid and fat synthesis, metabolism, and so on were identified. Functional category L (represented replication-, recombination-, and repair-related functions) was one of the most important categories with the highest relative abundance in all of the 23 major functional categories. CoG category having a significant correlation with Lactococcus piscium was the most abundant. The change in metabolic activity of bacteria at different fermentation time points showed that the metabolic activity was more active in the first 24 hr and then began to stabilize. LAB play the major role in the koumiss pH decreasing and quality improvement. The functional genes of related metabolic activity of lactic acid bacteria were more active in the first 24 hr of koumiss fermentation and then began to stabilize.

454 pyrosequencing reveals changes in the faecal microbiota of adults consuming Lactobacillus casei Zhang.

Probiotics are believed to help to maintain a healthy balance of the human gut microbiota. Lactobacillus casei Zhang (LcZ) is a novel potential probiotic isolated from the naturally fermented food koumiss. To better understand the impact of this potential probiotic on human intestinal microbiota, 24 subjects were randomly recruited for a longitudinal study: the subjects were required to consume LcZ for 28 days, and faecal samples were collected prior to, during and after the LcZ consumption phase. Alterations in the gut microbiota were monitored using 454 pyrosequencing and quantitative polymerase chain reaction(q-PCR) technologies. We found that the consumption of LcZ significantly altered the composition of intestinal microbiota (P < 0.001) and the gut microbiota diversity. Further analysis at the genus level revealed a positive correlation between LcZ and Prevotella, Lactobacillus, Faecalibacterium, Propionibacterium, Bifidobacterium and an unidentified genus from Bacteroidaceae and Lachnospiraceae and a negative correlation between LcZ administration and the presence of Clostridium, Phascolarctobacterium, Serratia, Enterococcus, Shigella and Shewanella. Furthermore, these changes were confirmed by q-PCR data.

Characterization of fecal microbiota across seven Chinese ethnic groups by quantitative polymerase chain reaction.

The human gut microbiota consists of complex microbial communities, which possibly play crucial roles in physiological functioning and health maintenance. China has evolved into a multicultural society consisting of the major ethnic group, Han, and 55 official ethnic minority groups. Nowadays, these minority groups inhabit in different Chinese provinces and some of them still keep their unique culture and lifestyle. Currently, only limited data are available on the gut microbiota of these Chinese ethnic groups. In this study, 10 major fecal bacterial groups of 314 healthy individuals from 7 Chinese ethnic origins were enumerated by quantitative polymerase chain reaction. Our data confirmed that the selected bacterial groups were common to all 7 surveyed ethnicities, but the amount of the individual bacterial groups varied to different degree. By principal component and canonical variate analyses of the 314 individuals or the 91 Han subjects, no distinct group clustering pattern was observed. Nevertheless, weak differences were noted between the Han and Zhuang from other ethnic minority groups, and between the Heilongjiang Hans from those of the other provinces. Thus, our results suggest that the ethnic origin may contribute to shaping the human gut microbiota.