Isolation and Molecular Characterization of Pigment Producing Bacteria from Soil of Different Locality of Assam

Pigment is the most attractive attribute and integral part of human life. The source of the pigment used for different applications is chemically synthesised. However, pigment produced from natural sources (such as plants and microorganisms) can also be applied as a coloring agent. In addition to being colorants, many natural pigments are also fascinating bioactive substances with possible health benefits. Agrochemicals, food, medicine, pharmacology, cosmetics, and numerous other industries use these compounds. In this study, a total of 7 pigmented colonies were isolated from the soil samples of different areas of Assam. Out of 7 pigmented colonies, 3 colonies showed orange color and 4 colonies showed yellow color. Based on the similarity of growth pattern and high intensity of pigmentation one colony from each pigment was picked for further studies. The isolated orange and yellow pigments were denoted as S1 and S2, respectively. With the help of Bergey’s Manual of Determinative Bacteriology the isolated pigmented strains were preliminary identified based on their morphological, microscopic, and biochemical characteristics and after that 16S rRNA gene sequencing helped to identify the bacteria at the species level and the strains were identified as (S1) Micrococcus aloeverae ON377368 and (S2) Exiguobacterium aestuarii ON377409. The identified strains Micrococcus aloeverae and Exiguobacterium aestuarii showed a high pigment production rate at specific optimized conditions such as at temperature 37°C, pH 6, and NaCl concentrations at 1.5-2% and strains also showed a good characteristic growth pattern at a specific time interval. Therefore, the present study may be a helpful step towards the large-scale manufacture of pigments and the extraction, purification, and characterization of the pigment extracted from these strains will lead to provide a potent eco-friendly natural dye in the industrial sector.