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The landfill is a cheap way of solid waste management in developing countries. The majority of landfills are non-sanitary and work as open garbage dumping sites and pose threats to public and environmental health. Therefore, an indepth understanding of the chemistry and microbiology of landfills is imperative to develop the right policies for landfill management. In the current study, we investigated the chemistry and microbiology of three Indian landfill sites using culture-based and culture-independent molecular approaches. Our data indicate that the nature of landfills varies from site to site in terms of chemistry, pollutants, and pathogens. We also enriched and cultivated three methanogens using an optimized medium and constructed two high-quality draft genomes from enriched microbiomes using metagenome-assembled genome approaches. The phylogenomic study of one draft genome showed the highest 93% sequence similarity with members of Methanomassiliicoccaceae and was always enriched with Acholoplasma and Anaerohalosphaera lusitana. Despite all the efforts, we did not isolate it in pure culture and hypothesized that for the cultivation of some not-yet-cultured methanogen, the presence of other organisms plays an important role, and their syntrophic interaction must be discerned for its successful cultivation in the future. Co-cultivation of amino acid-degrading organisms indicates that their co-culture can assist in boosting the growth of methanogens. In addition, our data indicated that landfill leachate contains a heavy load of pollutants and treatment is a must before discharge in nature or use in irrigation or biofertilizer. [ABSTRACT FROM AUTHOR]

Weissella confusa and Weissella cibaria strains isolated from the human‐ gut are considered as potential probiotics, but remain under‐explored owing to their ambiguous taxonomic assignment. The present study assesses the taxonomic resolution of 11 strains belonging to W. confusa and W. cibaria species and highlights the inter‐ and intraspecies variations using an array of phenetic and molecular methods. Remarkable genomic variability among the strains was observed by phylogenetic analysis using concatenated housekeeping genes (pheS, gyrB, and dnaA) along with 16S rRNA gene sequence, suggesting intraspecies variations; which is also supported by the phenetic data. Analysis showed that 16S rRNA gene sequence alone could not resolve the variation, and among the tested marker genes, signals from pheS gene provide better taxonomic resolution. The biochemical and antibiotic susceptibility tests also showed considerable variations among the isolates. Additionally, 'quick' identification using mass spectroscopy‐based matrix‐assisted laser desorption/ionization‐time of flight mass spectra was accurate up to genus only, and not species level, for the Weissella group. The study highlights need for inclusion of functional, phenetic, and multigene phylogenetic analysis in addition to 16S rRNA gene‐based identification for the Weissella group, to provide better resolution in taxonomic assignments, which is often a prerequisite for the selection of potential strains with biotechnological applications. [ABSTRACT FROM AUTHOR]

A growing interest in culturable diversity has required microbiologists to think seriously about microbial preservation. In addition to the isolation and cultivation of pure strains, adequate preservation without changes in morphological, physiological and genetic traits is necessary. This review consolidates different methods used for preservation of microorganisms with an emphasis on cryopreservation and lyophilization. The critical points of cryopreservation and lyophilization are highlighted to explain how several extrinsic and intrinsic factors affect the cell survival and recovery during the process of long-term preservation. Factors responsible for alteration in genotypic and phenotypic integrity of cultures during preservation and methods used for their evaluation have been incorporated. We emphasize the importance of depositories and highlight their current funding status. Future areas for preservation research, including cell dormancy, ecosystem and community level preservation and the effects of the viable but non-culturable state on post-preservation recovery of the cells are also discussed. [ABSTRACT FROM AUTHOR]