Pigments are compounds that are widely used in industries that come in a wide variety of colors, some of which are water-soluble. Nontoxic nature of pigment produced by a number of microorganisms make them environmentally friendly for utilization in dye, foodstuff, pharmacy, cosmetics and other industrial purposes. Moreover natural pigments produced from biological origin have medicinal importance as been used as antioxidant, antimicrobial, additives, color intensifiers, and anticancer as well as economically friendly. Some of Bacteria capable of producing pigment with different varieties of colors are Agrobacterium aurantiacum, Staphylococcus aureus, Chromobacterium violaceum, Serratia marcescens, Bacillus Spp, Flavobacterium sp, etc. colors are Pink-red, Golden Yellow, Purple, red, Creamy and yellow respectively. Industrial production of natural food colorants by microbial fermentation has several advantages such as cheaper production, easier extraction, higher yields through strain improvement, no lack of raw materials and no seasonal. Therefore the present study aimed at reviewing pigment produced by bacteria and its significance.

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The recovery of metagenome-assembled genomes is biased towards the most abundant species in a given community. To improve the identification of species, even if only dominant species are recovered, we investigated the integration of flow cytometry cell sorting with bioinformatics tools to recover metagenome-assembled genomes. We used a cell culture of a wastewater microbial community as our model system. Cells were separated based on fluorescence signals via flow cytometry cell sorting into sub-communities: dominant gates, low abundant gates, and outer gates into subsets of the original community. Metagenome sequencing was performed for all groups. The unsorted community was used as control. We recovered a total of 24 metagenome-assembled genomes (MAGs) representing 11 species-level genome operational taxonomic units (gOTUs). In addition, 57 ribosomal operational taxonomic units (rOTUs) affiliated with 29 taxa at species level were reconstructed from metagenomic libraries. Our approach suggests a two-fold increase in the resolution when comparing sorted and unsorted communities. Our results also indicate that species abundance is one determinant of genome recovery from metagenomes as we can recover taxa in the sorted libraries that are not present in the unsorted community. In conclusion, a combination of cell sorting and metagenomics allows the recovery of MAGs undetected without cell sorting.

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