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Melanin pigment was attracted significant interest as a photo-protecting natural polymer which applied in different fields like nanotechnology, food processing and biomedicine. Streptomyces cyaneus is used for melanin biosynthesis after optimizing its medium requirements. Tellurium dioxide nanoparticles (TeO2 NPs) were biosynthesized by the optimized melanin and gamma rays at room temperature. TeO2 NPs were characterized by UV–Vis., XRD, FTIR, HRTEM, DLS, EDX, and SEM mapping analysis. Antimicrobial activity of TeO2 NPs was tested against some pathogenic fungi and bacteria. The non-controlled free radicals produced from gamma rays were stopped by the natural melanin (stabilizing and capping agent). A proposed reaction mechanism for TeO2 NPs production was investigated. Data received from HRTEM and DLS analysis were calculated the average particles size of the spherical TeO2NPs and were found to be 75.0 nm. TeO2 NPs possesses a promising antifungal potential towards Aspergillus flavus, Aspergillus niger, and Aspergillus fumigatus (30.0, 20.0, and 19.0 mm ZOI, respectively). As well, they have antibacterial potential against Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumoniae (25.0, 18.0, and 15.0 mm ZOI, respectively). Based on TeO2 NPs characteristics as an encourage antimicrobial agent, it may be conducted as active ingredients in biomedicine, food processing and packaging and cosmetics. [ABSTRACT FROM AUTHOR]

Abstract Laccases are used for the conversion of biomass into fermentable sugars but it is difficult to produce high yields of active laccases in heterologous expression systems. We overcame this challenge by expressing Streptomyces cyaneus CECT 3335 laccase in Escherichia coli (ScLac) and we achieved a yield of up to 104 mg L−1 following purification by one-step affinity chromatography. Stability and activity assays using simple lignin model substrates showed that the purified enzyme preparation was active over a broad pH range and at high temperatures, suggesting it would be suitable for biomass degradation. The reusability of ScLac was also demonstrated by immobilizing the enzyme on agarose beads with a binding yield of 33%, and by the synthesis of cross-linked enzyme aggregates with an initial activity recovery of 72%.

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Melanin pigment is witnessed to be widely used in medicine, food, cosmetic preparations with strong hydrophobicity. Streptomyces cyaneus is utilized for the synthesis of melanin by optimizing culture conditions through screening of critical factors, by Response Surface Methodology as Plackett-Burman design (P-BD), while further statistical optimization was applied using Central Composite Design (CCD) for maximizing yield. Moreover, the impacts of gamma radiation and alternative frugal l-tyrosine, natural sources were studied as it predicted for remarkable rising in the pigment concentration. Herein unprecedented achievement was realized for melanin pigment production, (9.898 mg/ml) was obtaining by optimized culture condition. Also, 2.0% fava bean's seed peel maximized melanin (9.953 mg/ml) and hence super-yield (11.113 mg/ml) was produced by a stimulus from gamma irradiation (2.5 kGy). The extracted melanin was confirmed chemically, UV-Vis, and FT-IR analysis. Copper oxide nanoparticles (CuONPs) were synthesized by radiolytic reactions of gamma radiation (30.0 kGy) in the presence of melanin as a capping agent. CuONPs were characterized by UV-Vis, DLS, XRD, and FT-IR. TEM analysis revealed the morphology of monodispersed CuONPs with a mean diameter 29.82 nm. CuONPs exhibited excellent antimicrobial activity against food born Gram-positive, Gram-negative bacteria, and fungi; they can find potential applications for the food packaging approach. [ABSTRACT FROM AUTHOR]

Laccases are used for the conversion of biomass into fermentable sugars but it is difficult to produce high yields of active laccases in heterologous expression systems. We overcame this challenge by expressing Streptomyces cyaneus CECT 3335 laccase in Escherichia coli ( ScLac) and we achieved a yield of up to 104 mg L following purification by one-step affinity chromatography. Stability and activity assays using simple lignin model substrates showed that the purified enzyme preparation was active over a broad pH range and at high temperatures, suggesting it would be suitable for biomass degradation. The reusability of ScLac was also demonstrated by immobilizing the enzyme on agarose beads with a binding yield of 33%, and by the synthesis of cross-linked enzyme aggregates with an initial activity recovery of 72%. [ABSTRACT FROM AUTHOR]

Abstract: The ability of a laccase (EC 1.10.3.2) produced by Streptomyces cyaneus CECT 3335 to decolourise and detoxify azo dyes was assessed. Results showed that a colour loss of 90% was achieved only in the presence of acetosyringone (0.1mM) acting as a redox mediator for the laccase. Toxicological analysis of the decolourised dyes revealed that there was no direct correlation between decolouration and detoxification; in fact, in the case of the dyes Methyl Orange and Orange II, a significant increase in toxicity was produced after the treatment. In contrast, a significant decrease in toxicity was observed after the decolouration of New Coccine and Chromotrope 2R. Finally, HPLC analysis of the dyes after treatment revealed the complete disappearance of both dyes and mediator and a concomitant appearance of new chromatographic peaks which could be responsible of the residual toxicity detected in some cases. [Copyright &y& Elsevier]

Abstract: Streptomyces cyaneus SN32 was used in this study to produce extracellular xylanase, an important industrial enzyme used in pulp and paper industry. The enzyme was purified to homogeneity by ammonium sulfate precipitation followed by anion exchange chromatography using DEAE–Sepharose column, with 43.0% yield. The enzyme was found to be a monomer of 20.5kDa as determined by SDS gel electrophoresis and has a pI of 8.5. The optimum pH and temperature for purified xylanase activity was 6.0 and 60–65°C, respectively. The half-lives of xylanase at 50 and 65°C were approximately 200 and 50min, respectively. The xylanase exhibited K m and V max values of 11.1mg/ml and 45.45μmol/min/mg. The 15 residue N-terminal sequence of the enzyme was found to be 87% identical up to that of endoxylanases from Steptomyces sp. Based on the zymogram analysis, sequence similarity and other characteristics, it is proposed that the purified enzyme from S. cyaneus SN32 is an endoxylanase and belongs to Group1 xylanases (low molecular weight – basic proteins). The purified enzyme was stable for more than 20week at 4°C. Easy purification from the fermentation broth and its high stability will be highly useful for industrial application of this endoxylanase. [Copyright &y& Elsevier]

Aim: The present study aimed at optimization of cultural and nutritional parameters for enhanced production of xylanase from Streptomyces cyaneus SN32. Methods and Results: The xylanase production by S. cyaneus SN32 on most of the agro-residues tested in this study was more, as compared with the xylanase yield in the medium supplemented with commercial xylan. The presence of wheat bran as carbon source in the medium induced the highest production of xylanase followed by corn cob. Utilization of maize stalk, gram husk and black gram husk for microbial xylanase production has been reported first time in the present study. Among all the organic and inorganic sources of nitrogen tested in the study, peptone was found to be the best in stimulating xylanase production by S. cyaneus SN32. Conclusion: The production of xylanase from this thermoalkalophilic actinomycete has been enhanced 1·44-fold. To the best of our knowledge, the magnitude of enzyme yield i.e. 720 IU ml−1 by S. cyaneus SN32 has not been reported for any other actinomycete so far. Significance and Impact of Study: Present studies revealed that thermoalkalophilic S. cyaneus SN32, because of its simple nutritional requirements and its ability to exhibit considerably good enzyme yield, is a potent xylanase producer for its economical application in various industries. [ABSTRACT FROM AUTHOR]

The recent interest in the utilisation of agricultural fibres has promoted research into their potential as raw materials for the pulp and paper industry. In the current study, we report on the effect of biological pretreatment of wheat straw by Streptomyces cyaneus on the performance of the handsheets produced from the treated pulps. The pre-treatment of wheat straw with S. cyaneus had a positive effect on both the burst and tear indexes of the pulps but had a negative impact on tensile index. No significant variation in permeability and in folding endurance was observed. Manipulation of handsheets from wheat straw through biological treatment may therefore result in improved quality traits. [Copyright &y& Elsevier]

Background A nearly 4-year-old neutered male Australian Terrier was referred for a nodular pyogranulomatous mass of the right axilla. It had been poorly responsive to antibiotic therapy. Case report Based on filamentous Gram-positive organisms identified in earlier biopsy material, infection by an Actinomyces sp. was suspected and the dog showed clinical improvement on a trial of potentiated sulfonamides. Recurrence 5 months later prompted euthanasia, with Streptomyces cyaneus being cultured and confirmed by genetic sequencing of part of the 16 s ribosomal RNA gene. Conclusion Invasive Streptomyces spp. infections are uncommon in humans and animals, and isolations are sometimes considered to be contaminants, but the demonstration of the organism within the lesion in this instance indicates that the isolation of a Streptomyces sp. from veterinary cases should not always be considered as contamination, because this genus is clearly pathogenic. [ABSTRACT FROM AUTHOR]

In surface cultures of Streptomyces cyaneus var. viridochromogenes, NaCl depressed water activity ( a) without supporting growth. Reducing a from 0.987 to 0.951 led to 3- and 4-fold increases in intracellular and extracellular phenol oxidase activities, respectively. [ABSTRACT FROM AUTHOR]