Synthetic dye decolorization by three sources of fungal laccase

Decolorization of six synthetic dyes using three sources of fungal laccase with the origin of Aspergillus oryzae, Trametes versicolor, and Paraconiothyrium variabile was investigated. Among them, the enzyme from P. variabile was the most efficient which decolorized bromophenol blue (100%), commassie brilliant blue (91%), panseu-S (56%), Rimazol brilliant blue R (RBBR; 47%), Congo red (18.5%), and methylene blue (21.3%) after 3 h incubation in presence of hydroxybenzotriazole (HBT; 5 mM) as the laccase mediator. It was also observed that decolorization efficiency of all dyes was enhanced by increasing of HBT concentration from 0.1 mM to 5 mM. Laccase from A. oryzae was able to remove 53% of methylene blue and 26% of RBBR after 30 min incubation in absence of HBT, but the enzyme could not efficiently decolorize other dyes even in presence of 5 mM of HBT. In the case of laccase from T. versicolor, only RBBR was decolorized (93%) in absence of HBT after 3 h incubation. © 2012 Forootanfar et al.; licensee BioMed Central Ltd

Decolorization of two synthetic dyes using the purified laccase of Paraconiothyrium variabile immobilized on porous silica beads

BACKGROUND: Decolorization of hazardous synthetic dyes using laccases in both free and immobilized form has gained attention during the last decades. The present study was designed to prepare immobilized laccase (purified from Paraconiothyrium variabile) on porous silica beads followed by evaluation of both free and immobilized laccases for decolorization of two synthetic dyes of Acid Blue 25 and Acid Orange 7. Effects of laccase concentration, pH and temperature alteration, and presence of 1-hydroxybenzotriazole (HBT) as laccase mediator on decolorization pattern were also studied. In addition, the kinetic parameters (K( m ) and V( max )) of the free and immobilized laccases for each synthetic dye were calculated. RESULTS: Immobilized laccase represented higher temperature and pH stability compare to free one. 39% and 35% of Acid Blue 25 and Acid Orange 7 was decolorized, respectively after 65 min incubation in presence of the free laccase. In the case of immobilized laccase decolorization percent was found to be 76% and 64% for Acid Blue 25 and Acid Orange 7, respectively at the same time. Increasing of laccase activity enhanced decolorization percent using free and immobilized laccases. Relative decolorization of both applied dyes was increased after treatment by laccase-HBT system. After nine cycles of decolorization by immobilized laccase, 26% and 31% of relative activity were lost in the case of Acid Blue 25 and Acid Orange 7, respectively. CONCLUSIONS: To sum up, the present investigation introduced the immobilized laccase of P. variabile on porous beads as an efficient biocatalyst for decolorization of synthetic dyes

Isolation and molecular identification of halophilic protease producing actinomycete and evaluation of effective factors for maximal enzyme production

Introduction: Proteases are one of the most applicable hydrolyzing enzymes especially in food and beverage industries. Isolation of thermophilic or halophilic proteases was aimed by many investigations. The present study was designed to screen soil samples for halophilic actinomycetes capable to produce protease and evaluation of factors affect on the enzyme production.  Methods: Twenty soil samples were collected from salty land around Kerman, Iran and aseptically transferred to biotechnology lab and allowed to dry. Ten grams of each soil was extracted using NaCl (0.9%) sterile solution and added to Casein Glycerol Agar (CGA) or nutrient agar medium containing skim milk (1%) and NaCl (10%) and incubated at 30◦C untill the halo zone of protease activity was formed. The ratio of halo zone/colony size of isolated actinomyctes was used as an index to select the most suitable strains. Morphological and biochemical tests as well as molecular identification using 16S rDNA technique were then applied for identification of the strain. Evaluation of chemical factors such as carbon sources, nitrogen sources and inorganic salts as well as physical factors such as temperature and pH on protease production of the selected strain was performed using one factor at a time approach. Results: Seven protease-producing actinomycetes were isolated in preliminary studies among which one isolate (identified as Nocardiopsis sp.) was the most efficient one able to produce 650 U/mL protease after 5 days incubation in CG medium containing 10% NaCl. Evaluation of factors is now conducting to obtain the maximum protease production. Conclusion: one halophilic actinomycete able to produce protease was isolated in the present study and evaluation of factors affect on the enzyme production is now performing

Preparation and evaluation of niosomes containing autoclaved Leishmania major: a preliminary study

In this study, different positively charged niosomal formulations containing sorbitan esters, cholesterol and cetyl trimethyl ammonium bromide were prepared by film hydration method for the entrapment of autoclaved Leishmania major (ALM). Size distribution pattern and stability of niosomes were investigated by laser light scattering method and ALM encapsulation per cent was measured by the bicinchoninic acid method. Finally, the selected formulation was used for the induction of the immune response against cutaneous leishmaniasis in BALB/c mice. Size distribution curves of all the formulations followed a log-normal pattern and the mean volume diameter was in the range 7.57–15.80 mm. The mean volume diameters were significantly increased by adding Tween to Span formulations (p50.05). The percentage of ALM entrapped in all formulations varied between 14.88% and 36.65%. In contrast to ALM, in vivo studies showed that the niosomes containing ALM have a moderate effect in the prevention of cutaneous leishmaniasis in BALB/c mice

Photocatalytic decolorization of bromothymol blue using biogenic selenium nanoparticles synthesized by terrestrial actinomycete Streptomyces griseobrunneus strain FSHH12

The aim of the present study was to isolate and identify a terrestrial actinomycete bacterial strain capable to produce selenium nanoparticles (Se NPs) followed by purification of the biogenic Se NPs and evaluation of their photocatalytic degradation compared to selenium dioxide. Among 30 actinomycete bacterial strains obtained from environmental soil samples, one isolate (identified as Streptomyces griseobrunneus strain FSHH12 based on the 16S rDNA gene sequence analysis) was selected and used for production of Se NPs. The biologically synthesized Se NPs was consequently purified by an organic–aqueous partitioning system and characterized using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray, UV–visible spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction spectroscopy. The obtained results of photocatalytic degradation of bromothymol blue using the purified Se NPs (64 μg/mL) revealed 62.3% of dye removal under UV illumination (15 W) after 60 min incubation of dye solution

ANTIMICROBIAL ACTIVITY OF BACILLUS SP. STRAIN FAS1 ISOLATED FROM SOIL

During screening for antibiotic producing microorganisms from environmental soil samples, the supernatant of a bacterial isolate was found to have antibacterial and antifungal activity on the standard indicator species. The standard cylinder-plate method was used to determine the inhibitory effect of the crude supernatant of each isolate on 6 bacterial and 3 fungal standard strains by measuring the diameter of inhibition zone. The highest inhibition zone on Aspergillus niger belonged to culture broth of isolate FAS1 by 25 mm, and this isolate was the most efficient microorganism to inhibit standard bacterial and fungal species. Based on morphological and biochemical properties as well as 16S rDNA gene analysis, the selected isolate (isolate FAS1) belonged to Bacillus genus. Investigation on the ability of different culture media for antibiotic production led to select Luria-Bertani media for further studies. Treatment of the culture broth of the isolate FAS1 using typical protease didn’t decrease the antimicrobial activity of the supernatant. After extracting of culture broth of the selected isolate by ethyl acetate as an organic solvent, the inhibitory effect was mainly increased. More investigation was done by bioautography method where the ethyl acetate fraction of the broth culture was separated on TLC by chloroform:methanol, 60:40 as mobile phase and Rf were calculated for inhibition spots

RESEARCH AND REVIEWS: JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY Biosynthesis and Characterization of Selenium Nanoparticles Produced by Terrestrial Actinomycete Streptomyces microflavus Strain FSHJ31

ABSTRACT During last decades, study on the development of eco-friendly processes for the production of selenium nanoparticles (Se NPs) have received much attention due to hazardous effects of chemical compounds used for nanoparticle preparation. The present study was designed to screen actinomycete strains able to produce Se NPs. Among isolated bacterial strains, a terrestrial actinomycete strain which was tolerant to Se 4+ ions (200 µg/ml of) was launched as Se NPs producer. Morphological and biochemical characteristics as well as 16S rDNA gene analysis of the selected strain introduced it as Streptomyces microflavus strain FSHJ31. The biologically synthesized Se NPs was then purified using n-Octyl alcohol/water extraction system and characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR) techniques. Analysis of the particle size distribution pattern of biogenic Se NPs via laser light scattering method demonstrated the size range of 28-123 nm for Se NPs with the 48 nm NPs being the most frequent particles

Microwave-assisted biosynthesis of zinc nanoparticles and theircytotoxic and antioxidant activity

The present study was designed for microwave assisted synthesis of zinc nanoparticles (Zn NPs) usingLavandula vera leaf extract in the presence of ZnSO4(1 mM). The biogenic Zn NPs were then characterizedusing scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy(XRD), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR) techniques. There-after, the cytotoxic effect of ZnSO4and Zn NPs on different cell lines was investigated by MTT-basedcytotoxicity assay and their antioxidant properties were assessed using DPPH scavenging activity andreducing power assay. The SEM micrograph showed that the Zn NPs had spherical shape with the sizerange of 30–80 nm. For A549, MCF-7, HT-29, and Caco-2 cell lines treated with Zn NPs, the concen-tration necessary causing 50% cell death (IC50) was found to be 22.3 ± 1.1 �g mL−1, 86 ± 3.7 �g mL−1,10.9 ± 0.5 �g mL−1, and 56.2 ± 2.8 �g mL−1, respectively. In the case of ZnSO4, the same results (IC50) wereobserved at concentration of 81.6 ± 1.3 �g mL−1(A549), 121.0 ± 2.4 �g mL−1(MCF-7), 43.0 ± 1.4 �g mL−1(HT-29), and 85.7 ± 2.3 �g mL−1(Caco-2). The obtained results of antioxidant activity showed that theIC50values of butylated hydroxyanisole (BHA) and Zn NPs were 44 �g mL−1and 65.3 �g mL−1, respec-tively, while ZnSO4at concentration of 200 �g mL−1exhibited only 10.9% DPPH radical scavenging effect.Moreover, the reducing power of Zn NPs and BHA were significantly higher than ZnSO4(p < 0.05). To sumup, application of L. vera leaf extract combined with microwave heating energy led to simple and fastformation of Zn nanostructures exhibited higher antioxidant and cytotoxic activity compared to solubleZn+2ions. However, identification of the related mechanisms merit further studies