Synthesis, Optimization, and Characterization of Cellulase Enzyme Obtained from Thermotolerant Bacillus subtilis F3: An Insight into Cotton Fabric Polishing Activity.

The efficacy of 40 bacterial isolates obtained from hot spring water samples to produce cellulase enzymes was investigated. As a result, the strain Bacillus subtilis F3, which was identified using traditional and molecular methods, was selected as the most potent for cellulase production. Optimization was carried out using one-factor-at-a-time (OFAT) and BOX-Behnken Design to detect the best conditions for the highest cellulase activity. This was accomplished after an incubation period of 24 h at 45°C and pH 8, with an inoculum size of 1% (v/v), 5 g/l of peptone as nitrogen source, and 7.5 g/l of CMC. Moreover, the best concentration of ammonium sulfate for cellulase enzyme precipitation was 60% followed by purification using a dialysis bag and Sephadex G-100 column chromatography to collect the purified enzyme. The purified cellulase enzyme was characterized by 5.39-fold enrichment, with a specific activity of 54.20 U/mg and a molecular weight of 439 kDa. There were 15 amino acids involved in the purified cellulase, with high concentrations of 160 and 100 mg/l for glycine and proline respectively. The highest stability and activity of the purified cellulase was attained at pH 7 and 50°C in the presence of 150 ppm of CaCl2, NaCl, and ZnO metal ions. Finally, the biopolishing activity of the cellulase enzyme, as indicated by weight loss percentages of the cotton fabric, was dependent on concentration and treatment time. Overall, the thermotolerant B. subtilis F3 strain has the potential to provide highly stable and highly active cellulase enzyme for use in biopolishing of cotton fabrics.

Biological Treatment of Real Textile Effluent Using Aspergillus flavus and Fusarium oxysporium and Their Consortium along with the Evaluation of Their Phytotoxicity.

Twenty-one fungal strains were isolated from dye-contaminated soil; out of them, two fungal strains A2 and G2-1 showed the highest decolorization capacity for real textile effluent and were, hence, identified as Aspergillus flavus and Fusarium oxysporium based on morphological and molecular methods. The highest decolorization percentage of 78.12 ± 2.1% was attained in the biotreatment with fungal consortium followed by A. flavus and F. oxysporium separately with removal percentages of 54.68 ± 1.2% and 52.41 ± 1.0%, respectively. Additionally, ultraviolet-visible spectroscopy of the treated effluent showed that a maximum peak (λmax) of 415 nm was reduced as compared with the control. The indicators of wastewater treatment efficacy, namely total dissolved solids, total suspended solids, conductivity, biological oxygen demand, and chemical oxygen demand with removal percentages of 78.2, 78.4, 58.2, 78.1, and 77.6%, respectively, demonstrated a considerable decrease in values due to fungal consortium treatment. The reduction in peak and mass area along with the appearance of new peaks in GC-MS confirms a successful biodegradation process. The toxicity of treated textile effluents on the seed germination of Vicia faba was decreased as compared with the control. The shoot length after irrigation with effluents treated by the fungal consortium was 15.12 ± 1.01 cm as compared with that treated by tap-water, which was 17.8 ± 0.7 cm. Finally, we recommended the decrease of excessive uses of synthetic dyes and utilized biological approaches for the treatment of real textile effluents to reuse in irrigation of uneaten plants especially with water scarcity worldwide.

Antimicrobial, Antioxidant and Larvicidal Activities of Spherical Silver Nanoparticles Synthesized by Endophytic Streptomyces spp.

In this study, metabolites involved in the free-biomass filtrates for three endophytic actinomycetes of Streptomyces capillispiralis Ca-1, Streptomyces zaomyceticus Oc-5, and Streptomyces pseudogriseolus Acv-11 were used as biocatalysts for green synthesis of silver nanoparticles (Ag-NPs). Characterization of biosynthesized Ag-NPs was accomplished using UV-Vis spectroscopy, X-ray diffraction patterns (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), and particle size analyzer. The biosynthesized Ag-NPs showed maximum surface plasmon resonance (SPR) at 440 for strain Ca-1 and 450 for both strains of OC-5 and Acv-11. Nanoparticle spherical shape was recorded with size ranging from 23.77 to 63.14 nm, 11.32 to 36.72 nm, and 11.70 to 44.73 nm for Ca-1, Oc-5, and Acv-11, respectively. SEM-EDX analysis exhibited the weight percentages of 17.3, 22.3, and 48.7% for Ag-NPs synthesized by strains Ca-1, Oc-5 and Acv-11, respectively. The activities of biosynthesized Ag-NPs were concentration dependent and the obtained results confirmed the efficacy of Ag-NPs as antimicrobial agents against Gram-positive and Gram-negative bacteria as well unicellular and multicellular fungi. The MIC for Gram-positive bacteria, Gram-negative bacteria (E. coli), and eukaryotic microorganisms was 0.25 mM with clear zone ranging from 10.3 to 14.6 mm, while MIC for Pseudomonas aeruginosa was 1.0 mM for Ag-NPs synthesized by strain Ca-1 and 0.25 mM for those synthesized by strains Oc-5 and Acv-11. Moreover, Ag-NPs exhibited antimicrobial activity against four plant pathogenic fungi represented by Alternaria alternata, Fusarium oxysporum, Pythium ultimum, and Aspergillus niger at 2.0, 1.5, 1.0, and 0.5 mM of Ag-NPs with different degree. In vitro assessment of the antioxidant efficacy of biosynthesized Ag-NPs was achieved by scavenging assay of H2O2, reducing power of Fe3+, or total antioxidant assay. The results showed that antioxidant activities of Ag-NPs were concentration dependent with the highest activity at Ag-NP concentration of 2.0 mM. Furthermore, the biosynthesized NPs have prospective bioinsecticidal activity against Culex pipiens and Musca domestica. Green synthesis of NPs could be quite potential for the development of new bioactive compounds used in different biomedical applications.

Endophytic actinomycetes Streptomyces spp mediated biosynthesis of copper oxide nanoparticles as a promising tool for biotechnological applications.

In this study, two endophytic actinomycetes isolates Oc-5 and Acv-11, were isolated from healthy leaves of medicinal plant Oxalis corniculata L. These isolates were identified as Streptomyces zaomyceticus Oc-5 and Streptomyces pseudogriseolus Acv-11 using 16S rRNA gene sequence. Biomass extract of these strains were used as a greener attempt for synthesis of copper oxide nanoparticles (CuO-NPs). The synthesized NPs were characterized by UV-Vis spectroscopy, Fourier transform infra-red (FT-IR) spectroscopy, X-ray diffraction (XRD)' transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). Green synthesized NPs showed surface plasmon resonance (SPR) absorption band at 400 nm, crystalline nature, spherical-shaped with an average size of 78 nm and 80.0 nm for CuO-NPs synthesized using strain Oc-5 and Acv-11, respectively. The bioactivities of CuO-NPs were evaluated. Results revealed that CuO-NPs exhibited promising antimicrobial activity against prokaryotic and eukaryotic microbial cells (Gram positive bacteria, Gram negative bacteria, unicellular and multicellular fungi). In addition, it showed antimicrobial potential against phyto-pathogenic fungal strains Fusarium oxysporum, Pythium ultimum, Aspergillus niger and Alternaria alternata. We further explored the in vitro antioxidant activity and cytotoxicity for biosynthesized CuO-NPs. The results revealed that' scavenging and total antioxidant activity for NPs synthesized using Streptomyces pseudogriseolus Acv-11 was better than those synthesized by Streptomyces zaomyceticus Oc-5. Also, the morphological changes and cell viability for Vero and Caco-2 cell line due to NPs treatments were assessed using MTT assay method. Furthermore, Larvicidal efficacy against Musca domestica and Culex pipiens was evaluated. The results obtained in this study clearly showed that biosynthesized CuO-NPs exhibited effective bioactivity and, therefore, provide a base for the development of versatile biotechnological applications soon.

Biodegradation of feather waste by keratinase produced from newly isolated Bacillus licheniformis ALW1.

Keratinase are proteolytic enzymes which have gained much attention to convert keratinous wastes that cause huge environmental pollution problems. Ten microbial isolates were screened for their keratinase production. The most potent isolate produce 25.2 U/ml under static condition and was primarily identified by partial 16s rRNA gene sequence as Bacillus licheniformis ALW1. Optimization studies for the fermentation conditions increased the keratinase biosynthesis to 72.2 U/ml (2.9-fold). The crude extracellular keratinase was optimally active at pH 8.0 and temperature 65 °C with 0.7% soluble keratin as substrate. The produced B. licheniformis ALW1 keratinase exhibited a good stability over pH range from 7 to 9 and over a temperature range 50-60 °C for almost 90 min. The crude enzyme solution was able to degrade native feather up to 63% in redox free system.

Extracellular Alkaline Lipase from a Novel FungusCurvularia sp. DHE 5: Optimisation of Physicochemical Parameters, Partial Purification and Characterisation.

Thirty isolated fungal strains were screened for lipase production using Phenol Red plates, containing tributyrin as lipidic substrate, and a novel fungus identified genetically as Curvularia sp. DHE 5 was found as the most prominent strain. Various agro-industrial substrates were evaluated as inert supports for lipase production in solid-state fermentation. The highest yield of lipase ((83.4±2.2) U/g on dry mass basis) was reported with wheat bran medium after seven days of fermentation at pH=7.0, temperature of 30 °C, 70% moisture content, inoculum size of 1.27·107 spore/mL and 2% olive oil as an inducer. Supplementation of the medium with 0.05% KCl as an ion source further increased lipase production to (88.9±1.2) U/g on dry mass basis. The enzyme was partially purified through ammonium sulphate fractionation (40%) followed by dialysis, and its optimum pH and temperature were reported at 8.0 and 50 °C, respectively, with remarkable pH and thermal stability.