Dynamics of microbial populations and metabolites of fermenting saps throughout tapping process of ron and oil palm trees in Côte d'Ivoire.

Palm wine fermentation is a complex microbial process that evolves with tapping times. The dynamics in microbiota and metabolites throughout palm wine tapping days is still not established, which are critical for the distinctive characteristics of palm wine taste and quality, and thus the mastery of the daily quality fluctuation during tapping. We analyzed the changes in microbial community structure by amplicon sequencing of bacterial 16S rRNA gene and fungal internal transcribed spacer (ITS) region, and metabolite profile changes using mass spectrometry in palm wine collected over 25-30 days tapping of ron (Borassus aethiopum) and oil palms (Elaeis guineensis) from Côte d'Ivoire. The stage-wise collected palm wine samples showed distinct changes in microbial diversity and pH, supporting microbial community dynamics during palm wine tapping. Results highlighted the dominance of Saccharomyces cerevisiae in early stages and the emergence of non-Saccharomyces yeasts, particularly Hanseniaspora spp. in the later stages of oil palm wine tapping, vice versa in the case of ron palm wine tapping, with a unique presence of Saccharomycodes in the later stages (15-30 days). Fructophilic lactic acid bacteria (FLAB), mainly Fructobacillus and Leuconostoc, encountered in both types of palm wine tapping showed a decline at later stages of oil palm wine tapping. In this type of palm wine, acetic acid bacteria with genera Acetobacter and Glucanoacetobacter, by surpassing Lactobacillus in the last stage become dominant, whereas Lactobacillus remained dominant in ron palm wine throughout tapping days. The decline in the relative abundance of gevotroline and essential amino acids during the later stages of palm wine tapping (15-25 days) supports the difference in the health benefits of the palm wine obtained from different days of tapping, indicating that early stages of tapping is more nutritional and healthy than the later stages. The microbial dynamics may be a potential indicator of metabolite changes during palm sap fermentation, thus contributing to establish particular features of palm wines in different stages of tapping. This understanding of microbial ecology and chemical composition changes during palm wine tapping can be used as biomarkers to assess palm wine's quality and help to design an optimum starter culture.

Rothia santali sp. nov., endophytic bacteria isolated from sandalwood (Santalum album L.) seedling.

A novel, mustard yellow-pigmented aerobic bacterial strain designated AR01T was isolated from hypocotyl tissue of a sandalwood seedling from Bangalore, India. The 16S rRNA gene of strain AR01T had the highest 98.97% sequence similarity with Rothia halotolerans YIM 90716T (KCTC 19172) followed by Rothia kristinae PM 129T (NBRC 15354T) (97.31%) and Rothia koreensis P31T (JCM 15915) (97.11%), respectively. The strain AR01T was coccoid-shaped, non-motile, non-spore forming, oxidase negative and catalase positive. The strain AR01T has a genome size of 3.31 Mb containing 2993 protein-coding genes including 48 tRNA and 10 rRNAs spread across 84 contigs. The genomic DNA G + C content was 71.77 mol%. The calculated dDDH was 31.10% and the OrthoANI value was 85.27% when compared with its closest related type strain Rothia halotolerans YIM 90716T. The predominant cellular fatty acids were C16:0 iso, C15:0 anteiso and C17:0 anteiso. The strain AR01T contains major polar lipids including diphosphatidylglycerol and phosphatidylglycerol. The distinct physiological, biochemical characteristics and genotypic relatedness indicated that AR01T represents a novel species of the genus Rothia, for which the name Rothia santali sp. nov. (Type strain AR01T = MCC 4800T = JCM 35593T) is proposed.

High-Throughput Illumina MiSeq Amplicon Sequencing of Yeast Communities Associated With Indigenous Dairy Products From Republics of Benin and Niger.

Traditional Wagashi cheese and fermented cow milk are among the most popular dairy products appreciated by people from Benin, Niger, and the neighboring region. These products are the main source of protein in the diet of the low-income population in the region. The fermented milk is prepared by spontaneous fermentation without back-slopping. Whereas, the leaf extract of Calotropis procera is used for curdling the milk to prepare the soft Wagashi cheese. The present study aims to provide in-depth analysis of yeast communities associated with these traditional milk products by high-throughput Illumina MiSeq amplicon sequencing of internal transcribed spacer (ITS) region of fungal rRNA genes. A total of 60 samples, 20 samples of fermented milk each from Benin and Niger, and 20 samples of Wagashi cheese from Benin were used for analysis. The metagenomic investigation revealed that Kluyveromyces marxianus, Saccharomyces cerevisiae, Candida parapsilosis, and Sagenomella keratitidis were the predominant yeast species present in the traditional milk products. Furthermore, we noticed a high presence of K. marxianus (61.1% relative abundance) in the Wagashi cheese and S. cerevisiae (28.4% relative abundance) in the fermented milk of Niger. The presence of potential pathogenic yeast C. parapsilosis and S. keratitidis in these African milk products calls for further investigation to assess their safety. The predominant yeast K. marxianus and S. cerevisiae, recognized with generally regarded as safe (GRAS) status, could be further selected as starter culture along with lactic acid bacteria for developing controlled fermentation processes with enhanced product quality and safety.

Toxigenic and pathogenic potential of enteric bacterial pathogens prevalent in the traditional fermented foods marketed in the Northeast region of India.

The microbial risk involved with natural food fermentation is largely unknown. Here, we report the prevalence of enteric bacterial pathogens in the traditional fermented foods marketed in Northeast region of India. A total of 682 samples of 39 food types (broadly categorized into fermented soybean, bamboo shoot, fish, milk and pork products) collected over four different seasons from seven states of India were analyzed in this study. Cultivation-independent analysis by MiSeq amplicon sequencing of V4-V5 region of the 16S rRNA gene showed the bacterial community structure in the foods. Among the WHO prioritized foodborne bacterial pathogens, we detected the prevalence of phylotypes related to Clostridium botulinum, Bacillus cereus, Staphylococcus aureus, Clostridium perfringens, Listeria monocytogenes, and Escherichia coli in these ethnic foods. We also observed the occurrence of other well known human enteric pathogens like Proteus mirabilis, Clostridium difficile, and Yersinia enterocolitica. Further pathogen-specific qPCR assays confirmed a higher population (>107 cells/g) of B. cereus, P. mirabilis, and a C. botulinum related phylotype in the fermented soybean, fish, and pork products. We noticed a general trend of higher pathogen occurrence during the colder months without any seasonal variation of total bacterial load in the fermented foods. Further qPCR analysis on toxigenic and pathogenic potential, and toxins production by immunoassays showed that all the soybean samples and the isolated B. cereus cultures were positive for diarrheal toxins (Nhe and Hb1), and nearly half of the samples were positive for emetic toxin (cereulide). Similarly, the food samples and associated swarming P. mirabilis cultures were positive with the pathogenic factors like hemolysin (hpm), urease (ure) and multidrug resistance. However, we could not confirm the presence of botulinum neurotoxin (toxins A, B, E, and F) in the C. botulinum positive food samples. This is the first baseline data of the enteric bacterial pathogens prevalent in the traditional fermented foods of India, which will support the sustained effort of WHO to estimate the global foodborne disease burden. The unusual presence of P. mirabilis in the fermented foods marketed in the Indian region with high incidence of urolithiasis cases is a concern. Our study emphasizes the need of the hour to have a coordinated action to control and prevent the spread of enteric bacterial pathogens through fermented foods marketed in India. Moreover, replacing the indigenous process with a defined starter culture based controlled fermentation will enhance the safety of Indian fermented foods.

Comparative analysis of the gut microbiota in centenarians and young adults shows a common signature across genotypically non-related populations.

Gut microbiota is among the factors that may be involved in healthy aging. Broader and geographically spread studies on gut microbiota of centenarians can help in identifying a common signature of longevity. We identified an endogamous Indian population with high centenarian prevalence. Here, we compared the gut microbiota composition and fecal metabolites of a centenarians group (˜100 years) with young people (25-45 years) of the region with the high centenarian prevalence and the nearby region of low centenarian prevalence to decipher microbial-related longevity signatures. Also, we compared our results with publicly available datasets of similar groups including 125 centenarians from three countries (Italy, Japan, China). Our comparative analysis resulted in higher biodiversity within Ruminococcaceae in centenarians, with respect to younger adults, irrespective of their nationality. We observed bacterial signatures that are common among extremely old people of different nationality. Comparative metabolites profiling identified the fecal metabolic signature of extreme aging in the Indian study population. Our analysis of the co-occurrence network and bimodal distribution of several taxa suggested the establishment of a pervasive change in the gut ecology during extreme aging. Our study might pave the way to develop gut microbiota based biomarkers for healthy aging.