Chapter · January 016 doi: 10. 1515/9783110412789-008 citation reads 46 authors

6.2 Microbial sources of natural color

Two primary sources of natural pigments are plants and microorganisms. However, vegetal 

pigments have disadvantages (low water solubility, instability to light, heat or adverse pH) 

being only available in some seasons (Reviewed by Darshan and Manonmani, 2015). In con-

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 6 Microbial Pigments

trast, microbial pigments present more pigment stability in addition to their easily cultiva-

tion (Parekh et al., 2000). Moreover, fast grow microorganisms can be cultivated in cheap 

culture medium, and can produce different shades of colours (Reviewed by Darshan and 

Manonmani, 2015). Thus, the industrial production of natural food colorants by microbial 

has a pivotal role in the world presently.

Microorganisms produce a diversity of antibiotics, enzymes and pigments being a hopeful 

source for natural colors. Pigments are present in plants, bacteria, fungi and most organ-

isms (Tab. 6.1) providing attractive colors which gratify human beings. A huge collection of 

colorants obtained from natural sources such as animals (and especially insects), plants and 

microorganisms have been examined in order to obtain different compounds (Shahid et al., 

2013). For a review of background and history of pigments and production technologies see 

Venil et al. (2013).

Most microorganisms can be isolated and purified from different environmental sources 

such as water bodies, soil, plants, insects and animals. Some food colorants pigments are 

particularly studied (Delgado-Vargas et al., 2000). Pagano and Dhar (2014) reviewed recent 

reports on fungal pigments focusing on their potential use and significance for human 

benefit. They highlighted the importance of research on fungal pigments both for humans 

and natural systems. Additionally, there is enormous demand for coloring agents in indus-

tries like textile, plastic, paint, paper and printing (Tuli et al., 2014). Much interest was dedi-

cated to specific pigments, such as natural blue or red colorant for food industries; however, 

novel chemical classes from pigment produced by marine fungi are also investigated (Dufossé 

et al., 2014). Moreover, there is increasing interest to improve the bioactivity and produc-

tion of microbial pigments for their commercial use in pharmacological and medical fields 

(Reviewed by Tuli et al., 2014).

With regard to Bacteria, red-pigmented compounds, named Prodigiosins, synthezised by 

both Gram-negative and Gram-positive bacteria have potential applications as therapeutic 

drugs against cancer with little or no toxicity to organism (Darshan and Manonmani, 2015). 

However, the biological role of these pigments in the microbe itself remains unclear. 

A recent review by Babitha (2009) (Tab. 6.2) focused on fungal microorganisms of the 

genus Monascus, which produce red pigments, used for foods and named “Monascus pig-

ments”. Tuli et al. (2014) revised the microbial pigments as natural color sources highlight-

ing the potential of pigment producing microorganisms. They compiled sources of microbial 

pigments and their biological and clinical properties (antimicrobial, antioxidant, anticancer 

and anti inflammatory). Additionally, they showed a list of pigment producing microorgan-

isms together with anticipated bioactivity.

The technology for microbial pigment production at industrial scale is costly. However, low 

cost processes are increasingly investigated (Babitha, 2009). Efforts are being made to reduce 

the production cost of fermentation based microbial pigments. In order to assess the produc-

tion cost, economic comparison has been drawn between natural and synthetic pigments (Tuli 

et al., 2014). Cheaper substrates are necessary for the growth of selected microorganisms. Addi-

tionally, researchers demand for studies on chemical structure, mechanism of action and activ-

ity of microbial pigments in order to rethink strategies of terminal diseases (Tuli et al., 2014). 

In this regard, filamentous fungi have high potential for the production of food pigments 

due to their chemical and color diversity in their pigments and simple large scale cultivation.  

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6.3 Microbial pigments in natural sites