Bio-pigmentation and Biotechnological Implementations

Biological pigments are naturally occurring chemical compounds which appear as color and serve a variety of functional purposes such as absorbing ultra violet (UV) light in order to promote photosynthesis, desorbing certain UV wavelengths to protect organisms from photo damage, or to oblige as an attraction to other organisms in order to promote mating or pollination. The visual character of pigmentation also serves to be an indicator of quality. Color based evaluation is essential as it indicates fertility, nutritional value, flavor, toxicity, or spoilage in food. Human society has incorporated this knowledge of the instinctive perception of color into marketing by increasing the appeal of food items, pharmaceuticals, and cosmetics.

Both artificial food colors (AFCs) or synthetic pigments and natural pigments are used as color additives to augment or correct imperfections of a food’s natural color, indicate artificially flavored foods and medicines, or serve as decorative purpose. The color additives are being used to provide color to foods whose natural color would potentially degrade through shipment and storage when exposed to UV light, extreme changes in temperature or humidity. In these cases, artificial color additives whose chemical structures are stable and do not degrade under various conditions can be preferable for marketing purposes.

However, the quandary lies directly in the advantage of chemically stable compounds. Naturally occurring pigments are biological derivatives of organic compounds, which can be metabolically or chemically broken down because they serve to synchronize with organismal demands (Shindo and Misawa 2013; Oren, 2013). Whereas the artificial chemical colors are the derivatives of coal-tar and petroleum, which cannot be degraded completely. Therefore artificial pigments are potentially perilous to life because such chemical behaviors are asynchronous with biological function. Studies have shown how various AFCs are being linked to biological and neurological effects, such as contributing to attention deficit hyperactivity (ADHD) behaviors in children, affecting nutrient absorption and metabolism, and cancer (Arnold et al., 2012; Kobylewski and  Jacobson 2012; Sonuga-Barke et al., 2013; Lok et al., 2013; Smith et al., 2015; Vojdani and Vojdani, 2015).

The United States Food and Drug Administration’s (US FDA) under FD&C Act,” (Food, Drugs and Cosmetics Act), Title 21 of the Code of Federal Regulations (CFR) has approved use of color additives in food, and regarded as “GRAS” (Generally Recognized as Safe) (//www.fda.gov/ForIndustry/ColorAdditives/default.htm;
//www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/). The “safe” amount of an artificial color known as the acceptable daily intake (ADI), measured in parts per million (ppm) that industries are legally permitted to use in products. However, if organisms, specifically humans and animals, cannot metabolize artificial chemical compounds how much of a dose considered as “safe” for consumption remains questionable.

As the development and creation of new technologies continues to thrive and be advantageous to comprehensive human society, the increasing demand for natural alternatives of artificial coloring can be fulfilled. The biological pigments such as carotenoids, xanthophylls (i.e. b-carotene, lycopene, lutein, canthaxanthine, rhodoxanthin, astaxanthin, zeaxanthin, phycocyanin, monascin), violacein, and melanins for industrial applications in the food, pharmaceutical, and cosmetic industries are gaining great attention (Mata-Gomez et al, 2014; Bhosale and Bernstein, 2005; Stahl and Sies, 2005). Chromobacterium violaceum is a Gram-negative proteobacteria found in the soil and water in tropical and subtropical environments. The bacterium is able to live under anaerobic and aerobic conditions but violacein as pigment only occurs in aerobic condition. Violacein is a secondary metabolite and has great potential for pharmacological applications such as antibacterial, anti-trypanocidal, anit-ulcerogenic, and anticancer drug (Hoshino, 2011; Vaishnav and Demain, 2011; Duran et al., 2010;  Duran et al., 2007). Another well-studied bacterial pigment is prodigiosin, a bright red colored bacterial pigment produced by wide variety of bacterial taxa, including Gram-negative rods such as S. rubidaea, Vibrio gazogenes, Alteromonas rubra, Rugamonas rubra, and Gram-positive actinomycetes, such as Streptoverticillium rubrireticuli and Streptomyces longisporus. Prodigiosin has been proved to be effective as anti-microbial, anti-malarial, anti-cancer and immunosuppressive pigment. In vitro, prodigiosins have been shown to primarily target the cancer cells independently of the p53 status while little or no effect has been observed on normal cells. In addition, prodigiosins are effective in cancer cells with multidrug resistance phenotype and defects in the apoptotic pathways (Pandey et al., 2009; Vaishnav and Demain, 2011; Chang et al., 2011).

The unique microbial metabolic pathways in which bio-pigments are being synthesized could be the most appropriate methodologies to develop as safest form of natural pigmentation in industries. Understanding the genetic sequences for the biosynthetic metabolites provides further insight as to how genes can be manipulated in microorganisms to obtain higher yields of specific biological pigments.The broader impact of bio-pigments from microorganisms will implement these compounds into food science, pharmacology, and biomedical practices.

This project aims to introduce the basics and advancements made thus far in the biochemistry and bioprocessing of various bio-pigmentation from microorganisms (i.e. bacteria and fungi) as well as their implementation in biotechnology and therapeutics. The main aims are to (a) introduce readers to the wide variety of microorganisms (i.e. bacteria and fungi) and their capability of pigment production, (b) provide an overview of the methodologies applied to screen and identify the pigment producing microorganisms, (c) provide a literature review on diversity of pigment producing microorganisms, (d) discuss the molecular mechanism of pigment biochemistry in microorganisms, (e) discuss the use of bio-pigments in food feed and pharmaceutical industries, (f) discuss the regulations, challenges and implications of enforcements from regulatory agencies. These aims will be organized by invited research/ review articles from renowned researchers exploring bio-pigmentation among variety of microorganisms (i.e. bacteria and fungi), and differ in length and number of chapters, with the literature review section containing the bulk of the text.

The reader should first be enticed to read this book because of the extensive use of colors in food and related products as well as their usage in pharmaceutical industries (e.g. antibacterial, anti-trypanocidal, anti-ulcerogenic, and anticancer drug). There are positive and negative aspects of food alteration in relation to the artificial coloring. Among positives, seafood such as salmon fish and dairy product such as cheese, yogurt is being tied with human consumption; whereas negative aspects are seen in the color stabilization and accumulation in the environment. The biochemical pathways in which several derivatives of carotenoids and/or prodigiosin including other pigments being observed are equally important to address towards strengthen the promises of stable coloration in microbial factories.

The second section introduces the methodologies to explore the diversity of microorganisms from variety of sources including soil, plants and animals. The role of microbial adaptability under extreme conditions has been reported to reveal specific coloration in various microorganisms intra and extra-cellularly. The concept of this section will address to compare the different methodologies for color production and extraction. These methodologies may provide a common ground towards a feasible approach of coloration in food, feed, and pharmaceuticals.

The third section will review the literature based historical perspectives of color producing microorganisms making emphasis of established research into open market field of food and medical industries.

Food, feed and pharmaceutical coloration acts as a major source of wealth creation around the globe. Together with the third, fourth section will review the basic and current aspects of literature. The fourth section will rely on the information obtained from different methodologies and its interpretation of microorganisms and health initiatives. This section will be the longest as this section will have details of tools and methods adapted to screen and isolate variety of microorganisms, and discover new/ ideal ways to secure the food, feed and pharmaceutical coloration using bio-pigments. To enhance the color formation within microbial cells, the data interpretation towards translative research for industrial implication will further assist providing the clues of microbial metabolism in variety of growth medium under varying environmental conditions.

Systematic tools of systems biology (i.e. Genomics, Proteomics, and Metabolomics) are useful ways to identify how microorganisms respond to certain environmental factors. Understanding of stress responsive factors may reveal changes in the microbial metabolic networks as well as cellular responses (via gene and protein expression) among color producing microorganisms. In the fifth section, the interpretation of genomics and proteomics data, which has better capabilities, would significantly impact the core interest of this book. Further, the fifth section will also introduce the desired microbial traits and cloning of advantageous trait for microbial color production.

As regarded above, the US FDA under FD&C Act has approved use of color additives in food, feed and pharmaceuticals under GRAS category. The FDA names approved straight colors by FD&C prefix followed by a number. Some of these colors include FD&C Blue No.1, FD&C Blue No. 2, FD&C Green No.3, FD&C Red No.3, FD&C Red No.40, FD&C Yellow No. 5, and FD&C Yellow No. 6. Other color additives, such as Orange B an Citrus No. 40, are only approved for specific uses, such as enhancing the color of sausage casings and orange rinds, respectively. The interpretations of FDA’s stand on color additives will be discussed in the sixth section of this book exploring color regulations in the USA comparing to globally for safety of human and animal consumptions.