Download Chapter-2 Review of Literature

Chapter-2
Review of Literature
REVIEW OF LITERATURE
Pigments are chemical compounds that absorb light in the wavelength range of the UV
region. When the microbial cells are used to produce colors the term refers to microbial
pigments (Delgado-Vargas et al., 2000). Colors often provide an easy way of identifying
certain microbes; they are often used in names of species. For example, Rosenbach in
1884 named the golden-colored pathogen Staphylococcus aureus (Latin, ‘‘golden’’) to
distinguish it from non pigmented Staphylococci of the resident skin microflora that he
named Staphylococcus alba (Latin, ‘‘white’’). Mostly synthetic colors are not human
friendly. To counter the ill effect of
synthetic colorants, there is worldwide interest in
process development for the production of pigments from natural sources. To meet the
growing demands in the pharmaceutical industry, it is necessary to improve the
performance of the system and thus increase the yield. The growth and natural product
production of an organism are strongly influenced by medium composition, thus
optimization of media components and cultural parameters is the primary task in a
biological process. Microbial production of natural products is a promising alternative
with several advantages (Becker and Wittmann, 2011).
Pigments can be classified by their origin as natural, synthetic, organic or inorganic.
Natural pigments are produced by living organisms such as plants, animals and
microorganisms. Some naturally occurring pigments are: Riboflavin, β-carotene,
Canthaxanthin, Carotenoids, Prodigiosin, Phycocyanin, Violacein and Astaxanthin
(Malik et al., 2012). Riboflavin is a yellow water-soluble vitamin produced by many
micro-organisms. Traditional chemical synthesis of riboflavin is now being replaced by
commercially competitive biotechnological processes using ascomycetes Ashbyagossypii,
filamentous fungi Candida famata, or bacterium Bacillus subtilis (Stahmann et al., 2000).
It is used in baby foods, breakfast cereals, pastas, sauces, processed cheese, fruit drinks,
vitamin-enriched milk products, and some energy drinks. β-carotene: Phycomyces and
Mucor circinelloides (wild type) are a potential source of
β -carotene. The European
Union Committee considers that beta-carotene produced by fermentation of Blakeslea
trispora is equivalent to the chemically synthesized material used as food colorant and is
therefore acceptable for use as a coloring agent in foodstuffs (European Commission,
2000). Canthaxanthin is produced as the major carotenoid pigment by orange and dark
pink pigmented bacteriochlorophyll containing bradyrhizobium (photosynthetic) strains
isolated from stem nodules of Aeschynomene species and Halobacterium spp.
Canthaxanthins are potent antioxidants and inhibit the oxidation of lipids in liposomes.
Carotenoids are yellow to orange-red pigments that are ubiquitous in nature. A number of
microorganisms produce this pigment such as Serratia and Streptomyces. Carotenoids are
effective antioxidants and are widely used as food colorants. Majority of microbes
reported produce carotenoids belonging to Myxococcus (Browning et al., 2003),
Streptomyces (Takano et al., 2005), Mycobacterium, Agrobacterium (Yokoyama et al.,
1994) and Sulfolobus (Kull and Pfander, 1997). Prodigiosin is a multipurpose red
pigment, produced by various microorganisms such as Serratia marcescens, Vibrio
psychoerythrus,
Rugamonas
rubra,
actinomycetes,
such
as
Streptoverticillium
rubrireticuli and other eubacteria (Khanafari et al., 2006). It is known to have
antibacterial, anti-malarial, antineoplastic and antibiotic activity. Phycocyanin is a blue
pigment, produced by cyanobacteria which contain chlorophyll a. The blue colorant is
produced by the name spirulina (blue green alga), which is also the name of a dietary
supplement rich in proteins and consists of dried cyanobacteria. Violacein is a versatile
pigment from a bacterium Chromobacterium violaceum that exhibits several biological
activities. It has gained increasing importance in industrial markets, such as in medicine,
cosmetics, food and textiles (Malik et al., 2012).
2.1. Pigment producing microorganisms
Some of the most important natural pigments are cartenoids, flavonoids, tetrapirroles and
some xanthophylls as astaxanthin. The pigment most commonly used in industries is
beta-carotene which is obtained from some microalgae and cyanobacteria. Astaxanthin
(3, 3’-dihydroxy-b, b-carotene-4, 4’- dione) is a orange- red pigment and produced by
microorganisms such as red basidiomycetous yeast Xanthophyllomyces dendrorhous
(Golubev, 1995), green algae Heamatococcus pluvialis, Agrobacterium aurantiacum and
Xanthophyllomyces dendrorhous. Micro-organisms which have the ability to produce
pigments in high yields include species of Monascus, Paecilomyces, Serratia, Cordyceps,
Streptomyces and yellow-red and blue compounds produced by Penicillium herquei and
Penicillium atrovenetum, Rhodotorula, Sarcina, Cryptococcus, Monascus purpureus,
Phaffia rhodozyma, Bacillus sp., Achromobacter, Yarrowia and Phaffia also produce a
large number of pigments (Table 1). Monascus species, fungi which produce monascus
pigments, have long been used in production of traditional East Asian foods such as red
rice wine and red bean curd (Mohankumari et al., 2009).
Various species of fungi belonging to Phycomycetes, order mucorales in particular are
the prominent sources of beta-carotene. Actinomycetes had known to be produced
various kinds of antibiotics and moreover these antibiotics include many pigments.
Production of pigments by actinomycetes has been utilized as an important cultural
characteristic in describing the organisms. The global interest and demand in application
of the fungal pigments such as carotenoids, flavonoids, betalains, quinones and some
tetrapyrroles in dyeing of cotton, silk and wool has been reported in several studies and
increased due to the toxicity problems caused by those of the synthetic origin. The
production and evaluation of microbial pigments as textile colorants is currently being
investigated. Fungi are more ecological interesting source of pigments, since some fungal
species are rich in stable colorants such as anthraquinone. Several algae (Dunaliella,
Dictyococcus and Haematococcus), bacteria (many species of eubacteria in addition to
halobacteria in archaebacteria), some filamentous fungi (belong to lower fungi and
Ascomycetes),
yeasts
(Cryptococcus,
Phaffia,
Rhodosporidium,
Rhodotorula,
Sporidiobolus, and Sporobolomyces) are reported to produce carotenoids. Serratia is a
Gram negative bacterium and belongs to Enterobacteriacea family. Serratia marcescens
was differentiated from other enteric bacteria due to its characteristic red pigmentation.
However many species of Serratia are non-pigmented or vary widely in pigmentation.
Other well-known species include S. odorifera, S. liquifaciens, S. rubidaea, S. ficaria, S.
pymuthica and S. fonticola. Serratia marcescens produces a cell-associated pigment
called prodigiosin, which gives it the appearance of tiny blood red droplets on suitable
growth media. Much yeast Rhodotorula, Yarrowia lipolytica, Cryptococcus sp., Phaffia
rhodozyma are good source of microbial pigments. Astaxanthin is a red pigment, is found
in animals but rarely found in micro-organisms like P. rhodozyma. Algae produce a
number of pigments Dunaliella salina, which occurs singly in marine environment and
belongs to class chlorophyta, produced beta-carotene. Rhodophyta contains red pigment,
phycocyanin and phycoerythrins apart from the main pigment chlorophyll, which are red
or blue and also present in the species Cyanophyta and Cryptophyta. Microbes that have
been isolated from the marine environment are estimated less than 1-2% as a pure
culture, whereas 98-99% has not succeeded in any culturing techniques. Similarly, the
data on diversity of bacterial symbionts in the sea grass is also still very limited. It has
been reported that there are micro organisms associated with marine organisms is also
suspected to synthesize secondary metabolites similar to their host. Microbes isolated
from plants, which produce bioactive substances have been found to have greater activity,
even greater activity than the activity of the host plants. Pigments like carotenoids,
anthoquinone and chlorophyll have been produced from yeast, fungi, bacteria and algae.
In fungi Monascus species are known to produce well-known azaphilone pigments like
monascorubrin, rubropunctatin and more recently, monascus ones from a yellow
Monascus mutant have been identified. Monascorubrin and rubropunctatin have a unique
structure responsible for their high-affinity for compounds with primary amino groups
(Dikshit et al., 2011).
Table 1: Pigment producing micro-organisms (Malik et al., 2012)
Microoganism
Bacteria
Agrobacterium aurantiacum
Agrobacterium auranticum
Paracoccus carotinifaciens
Bradyrhizobium sp.
Flavobacterium sp., paracoccus
Corynbacterium insidiosum
Rugamonasrubra
Streptoverticillium rubrireticuli
Vibrio gaogenes
Xanthophyllomyces dendrorhous
Holoferax alexandrines
Staphylococcus aureus
Chromobacterium violaceum
Serratia marcenes
Pseudomonas aeruginosa
Xanthomonas oryzae
Janithinobacterium lividum
Algae
Haematococcus
Pigment/Molecule
Color/Appearance
Astaxanthin
Astaxanthin
Canthaxanthin
Zeaxanthin
Indigoidine
Prodigiosin
Prodigiosin
Prodigiosin
Astaxanthin
Canthaxanthin
Staphloxanthin, Zeaxanthin
Violacein
Prodigiosin
Prodigiosin
Pycocyanin
Xanthomonadin
Violacein
Pink-red
Pink-red
Dark-red
Yellow
Blue
Red
Red
Red
Pink-red
Dark-red
Golden-yellow
Purple
Red
Red
Blue-green
Yellow
Purple
Astaxanthin
Red
Monascus sp.
Monascorubramin,
Rubropunctatin
Monascus purpureus
Monascein, Ankaflavin
Monascus roseus
Canthaxanthin
Monascus sp.
Ankaflavin
Pencillium oxalicum
Anthraquinone
Blakeslea trispora
Lycopene
Cordyceps unilateralis
Naphthoquinone
Ashbyagossypi
Riboflavin
Mucor circinelloides, Neurospora β-carotene
crassa
and
Phycomyces
blakesleeanus
Pacilomyces farinosus
Anthraquinone
Yeast
Phaffia rhodozyma
Astaxanthin
Rhodotorula sp. Rhodotorula Torularhodin
glutins
Actinomycetes
Streptoverticillium rubrireticuli
Prodigiosin
Red-orange
Red-yellow
Orange-pink
Yellow
Red
Red
Deep blood red
Yellow
Yellow-Orange
Red
Pink-red
Orange-red
Red
2.2. Applications of pigments
Synthetic dyes have some limitations, primarily (i) their production process requires
hazardous chemicals, creating worker safety concerns, (ii) they may generate hazardous
wastes, and (iii) these dyes are not environment friendly (Venil et al., 2013). The
currently used colorants are almost exclusively made from non-renewable resources such
as fossil oil. Currently pigments of various kinds and forms have been used as additives
or supplements in the food industry, cosmetics, pharmaceuticals, livestock feed and other
applications. However, because of the problems of the synthetic pigments that cause
toxicity and carcinogenicity in the human body, their use is gradually decreased.
Therefore interest in natural pigments that can replace synthetic dyes is increasing.
Recently in response to this trend, the tendency to use natural pigments as adding natural
materials in the natural dyeing, healthy functional foods, cosmetic products for human
health and safety have been gradually expanded.
a.) Applications as food colorant:
The development of foods with an attractive appearance is an important goal in the food
industry. Increasingly, food producers are turning to natural food colors, since certain
artificial color additives have demonstrated negative health issues following their
consumption. Due to the lack of availability of natural food colorants, its demand is much
sought especially in the food industry. Though many natural colors are available,
microbial colorants play a significant role as food coloring agent, because of its
production and easy down streaming process. A fungus strain Penicillium oxalicum with
the properties to produce a red colorant can be applied in food and cosmetic industries
(Sardaryan et al., 2004). These natural colorants are used in baby foods, breakfast cereals,
pastas, sauces, processed cheese, fruit drinks, vitamin-enriched milk products and some
energy drinks. Thus, natural colors in addition to being environment friendly, can also
serve the dual need for visually appealing colors and probiotic health benefits in food
products (Nagpal et al., 2011). The carotenoids are molecules formed by isoprenoids
units and the most important used as colorant are the alpha and beta carotene which are
precursors of vitamin A, and some xantophylls as astaxanthin. The pigment more used in
the industry is the beta-carotene which is obtained from some microalgae and
cyanobacteria (Yokoyama et al., 1994). Monascus sp., a filamentous fungus has been
used to make rice wine, soybean cheese and anka (red rice) in many Asian countries
(especially Japan and China) for centuries. Strains of Monascus species are known to
produce several polyketide bio-pigments (Watanabe et al., 1997).
Microorganisms are associated with all the foods that we eat and are responsible for the
formation of certain food products by the process of fermentation and can also be used as
a source of food in the form of single cell proteins and food supplements in the form of
pigments, amino acids, vitamins, organic acids, and enzymes. In this way the pigments
from microbial sources are a good alternative. It can also help to overcome the growing
public concern over the adverse health effects of addition of synthetic colors in food
products. Furthermore, natural colorants will not only be beneficial to the health of
human beings, but it will be a boon for the preservation of biodiversity as harmful
chemicals released into the environment while producing synthetic colorants could be
stopped.
b.) Applications in textile industry:
The textile industry produces and uses approximately 1.3 million tons of dyes, pigments
and dye precursors, valued at around U$23 billion, almost all of which is manufactured
synthetically. However, synthetic dyes have some limitations. These dyes are not
environment friendly. Practically, fermentation of microorganisms such as fungi and
bacteria could be a valuable source of manufacturing colorants.
Ahmad et al. (2012) characterized the red pigment prodigiosin (Serratia marcescens) and
violet pigment violacein (Chromobacterium violaceum) and tested its dyeing efficiency
in different fabrics i.e., pure cotton, pure silk, pure rayon, jacquard rayon, acrylic, cotton,
silk satin and polyester. Their results suggested that prodigiosin could be used to dye
acrylic and for violacein intense colorations was observed in pure rayon, jacquard rayon
and silk satin. Anthraquinone compounds have shown remarkable antibacterial activity in
addition to providing bright colors (Frandsen et al., 2006), which could serve as
functional dyes in producing colored antimicrobial textiles. Biosynthesis of pigments
through fermentation processes can serve as major chromophores for further chemical
modifications, which could lead to colorants with a broad spectrum of colors. Natural
dyes are non-toxic, non-polluting and less hazardous. Moreover, their antioxidant and
antimicrobial nature further adds positive effects (Hobson and Wales, 1998).
c.) Applications in pharmaceutical industry:
Most studies investigating micro-organisms have shown the efficacy and the potential
clinical applications of pigmented secondary metabolites in treating several diseases and
they also have certain properties like antibiotic, anticancer and immune-suppressive
compounds. Bacteria possess huge ability in producing biopigments that are synthesized
for producing medicinally important products. Xanthophylls, such as adonirubin and
astaxanthin may also act as nutraceuticals that prevent carcinogenesis through antioxidative, anti-free radical or other mechanisms (Cho et al., 2012). The beneficial
nutraceutical functions of the carotenes and xanthophylls extend to the prevention of
heart attacks and strokes (Long, 2004). Astaxanthin, another important carotenoid is a red
pigment of great commercial value, and it is used in the pharmaceutical feed.
Prodigiosins are strong therapeutic molecules especially for their immunosuppressive
properties and anticancer properties. The immunosuppressive properties were also carried
earlier by Han et al (1998).The pigment from Hahella chejuensis was also studied as
immunosuppressant and antitumor agent (Kim et al., 2008).
Significant progress has been achieved in this field, and investigations of bioactive
compounds produced by these microbes are rapidly increasing. As such, the number of
compounds isolated from bacteria is increasing faster when compared with other sources.
Violacein exhibits significant biological activities such as strong inhibition of several
tumor cell lines as well as antibacterial and trypanocidal activities. Carotenoids can
inhibit various types of cancer and it enhances the immune response (Guerin et al., 2003).
Anthocyanins are involved in a wide range of biological activities (Kong et al., 2003) that
affect positively the health properties and decrease the risk of cancer, reduce
inflammatory insult (Youdim et al., 2002) and modulate immune response (Wang et al,
2002). Pyocyanin is Blue-green pigment produced by Chromobacterium violaceum,
Janthinobacterium lividum has important role in oxidative metabolism, reducing local
inflammation. Carotenoids have attracted superior attention as compared to synthetic
pigments due to the beneficial role on human health. These pigments are capable of
quenching photo sensitizers; interacting with singlet oxygen (Krinsky et al., 1994) and
scavenging proxy radicals (Conn et al., 1992). They play an important role in protection
of macular region of the retina and hence prevents of cataracts and increases levels of
iron absorption (Mares et al., 2002). Carotenoids also play important roles for health and
human survival. Carotenoids are believed to improve the better immune responses,
protection from cancer (Temple and Basu, 1988), function as an antioxidant (Santamaría
et al., 1988)
and also used in the treatment of diseases that are sensitive to light
(Mathews, 1964).
d.) Applications in other aspects:
Ahmad et al. (2012) evaluated the potential of prodigiosin in coloring candles, paper,
soap and pencil case pouch and also tested the potential of prodigiosin and violacein as
ink in ball point pen and high lighter pen. Microbial colors are in use in the fish industry
already, for example to enhance the pink color of farmed salmon. Xanthan gum is a
microbial exopolysaccharide produced by the phytopathogenic bacterium Xanthomonas
campestris. It is widely used as a food ingredient and as one of the main components in
water-based drilling fluids in petroleum industries. In addition, due to its unique
rheological and other physicochemical properties, it plays various roles in a broad range
of industries such as toiletries, cosmetics, water-based paints, textile, ceramics etc.
Zeaxanthin is yellow pigment produced by Flavobacterium sp., Paracoccus
zeaxanthinifaciens, Staphylococcus aureus and Xanthomonas oryzae used as an additive
in poultry feed, strengthen yellow color of skin of animals and accentuate the color of
yolk of eggs. Phenanzine pigments are known from several bacterial genera in more than
50 varieties, each of which contains a substituted phenazine ring system, and together
they represent every color of the visible spectrum. Phenazines are derived from the
shikimic acid pathway via phenazine-1, 6-dicarboxylicacid and seem to be precursors for
further metabolism or are used as redox systems (Venil et al., 2013).The
phycobilliproteins obtained from cyanobacteria and some group of algae, have recently
been increased on the food industries. In the last years, it has been used
as fluorescent marker in biochemical assays.
Table 2: Applications of Microbial pigments
Pigment
Riboflavin
Beta carotene
Colour
Yellow
Yelloworange
Applications
Baby foods,
breakfast cereals,
pastas, sauces,
processed cheese,
fruit drinks,
vitamin-enriched
milk products and
some energy
drinks
Coloring agent in
foodstuffs
References
(Stahmann et al.,
2000)
(European
Commission,
2000).
Canthaxanthin
Orange
Antioxidants and
inhibit the
oxidation of lipids
in liposomes
Browning et al.,
2003, Takano et
al., 2005),
(Yokoyama et
al., 1994) and
Sulfolobus(Kull
and Pfander,
1997).
Golubev, 1995
Astaxanthin
Red
Feed,
pharmaceutical
and aquaculture
industries
Carotenoids
YellowOrange-red
Antioxidants and
are widely used
as food colorants
Prodigiosin
Red
Antibacterial,
anti-malarial,
antineoplastic and
antibiotic activity
Phycocyanin
Blue
Dietary
supplement rich
in proteins
Malik et al.,
2012
Violacein
Purple
Medicine,
cosmetics, food
and textiles
Malik et al.,
2000
(Browning et al.,
2003) (Takano
et al., 2005),
(Yokoyama et
al., 1994) and
Sulfolobus(Kull
and Pfander,
1997).
Khanafari et al.,
2006
2.2. Future perspectives:
Use of microbial pigments in processed food is promising with large economic potential.
Biosynthesis of colorants for textile applications has attracted increased interest in recent
years. Nature produces many biocolorants from various resources including plants,
animals, and microorganisms, which are possible alternatives to synthetic dyes and
pigments currently employed. (Mapari et al, 2005). Alihosseini et al, (2008)
characterized the bright red pigment prodigiosin from Vibrio sp. and suggested that it
could be used to dye many fibers including wool, nylon, acrylics and silk. There is an
urgent need for alternative colorants that are natural, cost effective and easily degradable
and without production of recalcitrant intermediates when they enter the ecosystem.
There is an increasing interest involving microorganisms as a possible alternate source of
colorants used in food industry. In this direction, biotechnology may play a crucial role
for large fermentation of natural biocolorants.