الفهرس 
Production of melanin pigment.
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Abstract
In the current study, detection of melanin - producing Streptomyces sp
and Aspergillus niger for producing high quantities of brown (Mel1), and black
(Mel2) melanin pigments, in order to achieve the productive efficiency and
tolerance under biosorption capacity of the selected strains against lead and
cadmium ions stress. Evaluation and estimation of the protective action of
microbial Mel pigments against Escherichia coli infection in Swiss albino
mice were discussed.
A comparison of the description of the selected strain with the
descriptions of Streptomyces showed that the selected actinomycete strain had
chemotaxonomic properties, cultural and morphological characteristics that
were consistent with the genus Streptomyces. Spirals spore chain, produce Mel
pigment and a Knobby spore surface. The mol % G + C of the DNA was 71.0,
negative gram stain, acid fast negative, phospholipids was PII, no diagnostic
sugar in the whole cell, and the cell wall chemotype I contain L-DAP acid. The
molecular identification of Streptomyces sp revealed 99% similarity with other
strains of Streptomyces sp accessed from GenBank to Streptomyces
longisporoflavus NRRL ISP-5165 (Accession NO: NR043826). The mycelial
and conidia morphology of Aspergillus niger were performed as a smooth and
colorless conidiophores and spores. Aspergillus niger recorded the highest
multi heavy metals resistance was identified and revealed 99.9% similarity
with other strains of A. niger as accessed from GenBank (Accession NO:
MT355517).
The most significant factors affecting on Mel1 production and S.
longisporoflavus NR043926 growth were darkness, starch nitrate media, initial
pH 7.0, 10 days of incubation at 30ºC, while Sabouraud’s medium, initial pH 7.0, 21 days of incubation at 30ºC for Mel2 production and A. niger
MT355517 growth.