4. Discussion
Bio-pigments are a special group of natural pigment, which
include coloring agents produced by microorganisms, especially
by Monascus spp. However, composition of pigments varies significantly
depending on the types of nutrients available, such as
nitrogen sources as well as the specific strains used [14]. The
working strain of M. purpureus could produce a range of pigments
(yellow, orange, and red) and dominated by red under suitable
conditions (pH 6.0 and temperature 30 ◦C). The red pigment with
relatively high maximum absorption, along with orange-yellow
pigments of lowermaximumabsorption spectra was observed [17].
The present study indicates the influence of pH for quality
of pigment production. In higher pH, consolidation of red pigment
production was observed. Quality of pigment production by
Monascus spp. was found to be reversible in acidic and towards
alkaline pH [18]. It appeared that the product reacts with ammoniumion
or free amino groups to transform to red amine derivatives
towards neutrality and beyond [19].
In the present study the growth of cells and pigment production
were found to be influenced by temperature. Earlier also it was
reported that temperature plays a pivotal role in cell metabolism,
thus influencing pigment production [4]. In this study, the experiment
was carried out within the range of 25–40 ◦C to minimize
the scope of transformation of pigments at higher temperature as
reported earlier [17]. It was found in this study that glucose at 18 g/L
was optimum for red pigment production. Lowering of the pigment
production was observed above this concentration, perhaps due to
respire-fermentative metabolism. This finding was in contrary to
the positive relationship of pigment to carbon [14].
Pigment production could notably vary with nitrogen supplementation
in Monascus [20]. The production of red pigment
dominated when medium was supplemented with monosodium
glutamate (MSG). The pigment production recorded maximum
(72 U/g dry cell mass) by supplementing 0.3% MSG which conforms
the finding of Miyake et al. [14]. They recorded enhanced
yellow pigment production with addition of 0.5% MSG whereas
another report [12] suggested ammonium and peptones superior
for growth and pigment concentration.
The pigment produced in fermentation broth was extracellular.
Various solvent systems were used for extraction and purification
4. DiscussionBio-pigments are a special group of natural pigment, whichinclude coloring agents produced by microorganisms, especiallyby Monascus spp. However, composition of pigments varies significantlydepending on the types of nutrients available, such asnitrogen sources as well as the specific strains used [14]. Theworking strain of M. purpureus could produce a range of pigments(yellow, orange, and red) and dominated by red under suitableconditions (pH 6.0 and temperature 30 ◦C). The red pigment withrelatively high maximum absorption, along with orange-yellowpigments of lowermaximumabsorption spectra was observed [17].The present study indicates the influence of pH for qualityof pigment production. In higher pH, consolidation of red pigmentproduction was observed. Quality of pigment production byMonascus spp. was found to be reversible in acidic and towardsalkaline pH [18]. It appeared that the product reacts with ammoniumionor free amino groups to transform to red amine derivativestowards neutrality and beyond [19].In the present study the growth of cells and pigment productionwere found to be influenced by temperature. Earlier also it wasreported that temperature plays a pivotal role in cell metabolism,thus influencing pigment production [4]. In this study, the experimentwas carried out within the range of 25–40 ◦C to minimizethe scope of transformation of pigments at higher temperature asreported earlier [17]. It was found in this study that glucose at 18 g/Lwas optimum for red pigment production. Lowering of the pigmentproduction was observed above this concentration, perhaps due torespire-fermentative metabolism. This finding was in contrary tothe positive relationship of pigment to carbon [14].Pigment production could notably vary with nitrogen supplementationin Monascus [20]. The production of red pigmentdominated when medium was supplemented with monosodiumglutamate (MSG). The pigment production recorded maximum(72 U/g dry cell mass) by supplementing 0.3% MSG which conformsthe finding of Miyake et al. [14]. They recorded enhancedyellow pigment production with addition of 0.5% MSG whereasanother report [12] suggested ammonium and peptones superiorfor growth and pigment concentration.The pigment produced in fermentation broth was extracellular.Various solvent systems were used for extraction and purification
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