MICROORGANISMS
THAT PRODUCE PIGMENT Bacteria, yeasts, and fungi are the main microorganisms capable of producing natural pigments (Celedón & Díaz, 2021). In the case of fungi, multiple pigments have been described and have been used for years as taxonomic identifiers. Some of them are commercially available for cell staining and protein detection as well as being used as replacements for the production of synthetic dyes in the textile industry. The benefits of using bacteria for pigment production over other natural dyes such as fungi are that bacteria have a short life cycle and ease of genetic modification. The problem with bacterial dyes is that most bacterial pigments are still at the research and development stages, unlike fungal dyes. Like fungi, bacteria produce pigments such as violacein (purple), melanin (dark brown), carotenoids (orange), prodigiosin (red), and pyocyanin (blue) (Narsing Rao et al., 2017). Bacteria produce pigments for multiple reasons, mainly due to morphological characteristics, cellular activities, pathogenesis, protection
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and survival. Some of the bacteria that produce green pigments, such as autotrophic cyanobacteria, have chlorophyll (similar to plants), which is needed to carry out photosynthesis. Other pigments are produced by bacteria to absorb UV radiation or to quench oxygen free radicals. In some cases, bacterial pigment is needed for cell protection. Other pigments serve as antibiotics against phytopathogenic fungi, other bacteria and yeasts, or heavy metals resistance. Pigments may also maintain cell membrane integrity and stability (Bhawsar, 2011). This shows that the pigment occurs naturally by the bacteria for its own functions within its environment. Table 1 shows a list of all bacterial pigments, their biological activities and reported genera of pigment producers. The reported producers with an * at the end are currently being explored in the lab to obtain their pigments on textiles for the fashion collection mentioned in the introduction.
