Search tips
Search criteria

Results 1-5 (5)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Comparative sequence analysis of citrate synthase and 18S ribosomal DNA from a wild and mutant strains of Aspergillus niger with various fungi 
Bioinformation  2014;10(1):1-7.
A mutation was induced in Aspergillus niger wild strain using ethidium bromide resulting in enhanced expression of citric acid by three folds and 112.42 mg/mL citric acid was produced under optimum conditions with 121.84 mg/mL of sugar utilization. Dendograms of 18S rDNA and citrate synthase from different fungi including sample strains were made to assess homology among different fungi and to study the correlation of citrate synthase gene with evolution of fungi. Subsequent comparative sequence analysis revealed strangeness between the citrate synthase and 18S rDNA phylogenetic trees. Furthermore, the citrate synthase movement suggests that the use of traditional marker molecule of 18S rDNA gives misleading information about the evolution of citrate synthase in different fungi as it has shown that citrate synthase gene transferred independently among different fungi having no evolutionary relationships. Random amplified polymorphic DNA (RAPD-PCR) analysis was also employed to study genetic variation between wild and mutant strains of A. niger and only 71.43% similarity was found between both the genomes. Keeping in view the importance of citric acid as a necessary constituent of various food preparations, synthetic biodegradable detergents and pharmaceuticals the enhanced production of citric acid by mutant derivative might provide significant boost in commercial scale viability of this useful product.
CS - Citrate synthase, CA - Citric acid, RAPD - Random amplified polymorphic DNA, TAF - Total amplified fragments, PAF - Polymorphic amplified fragments, CAF - Common amplified fragments.
PMCID: PMC3916811  PMID: 24516318
citrate synthase; Aspergillus niger; phylogenetic analysis; polymorphism; RAPD-PCR
2.  Enhanced decolorization of Solar brilliant red 80 textile dye by an indigenous white rot fungus Schizophyllum commune IBL-06 
An indigenously isolated white rot fungus, Schizophyllum commune IBL-06 was used to decolorize Solar brilliant red 80 direct dye in Kirk’s basal salts medium. In initial screening study, the maximum decolorization (84.8%) of Solar brilliant red 80 was achieved in 7 days shaking incubation period at pH 4.5 and 30 °C. Different physical and nutritional factors including pH, temperature and fungal inoculum density were statistically optimized through Completely Randomized Design (CRD), to enhance the efficiency of S. commune IBL-06 for maximum decolorization of Solar brilliant red 80 dye. The effects of inexpensive carbon and nitrogen sources were also investigated. Percent dye decolorization was determined by a reduction in optical density at the wavelength of maximum absorbance (λmax, 590 nm). Under optimum conditions, the S. commune IBL-06 completely decolorized (100%) the Solar brilliant red 80 dye using maltose and ammonium sulfate as inexpensive carbon and nitrogen sources, respectively in 3 days. S. commune IBL-06 produced the three major ligninolytic enzymes lignin peroxidase (LiP), manganase peroxidase (MnP) and lacaase (Lac) during the decolorization of Solar brilliant red 80. LiP was the major enzyme (944 U/mL) secreted by S. commune IBL-06 along with comparatively lower activities of MnP and Laccase.
PMCID: PMC3824141  PMID: 24235871
S. commune IBL-06; Direct dye; Solar brilliant red 80; Bio-remediation; Ligninolytic enzymes
3.  Decolorization applicability of sol–gel matrix immobilized manganese peroxidase produced from an indigenous white rot fungal strain Ganoderma lucidum 
BMC Biotechnology  2013;13:56.
An eco-friendly treatment of industrial effluents is a major environmental concern of the modern world in the face of stringent environmental legislations. By keeping in mind the extensive industrial applications of ligninolytic enzymes, this study was performed to purify, and immobilize the manganese peroxidase (MnP) produced from an indigenous strain of Ganoderma lucidum. The present study was also focused on investigating the capability of immobilized MnP for decolorization of dye containing textile effluents.
A large magnitude of an indigenous MnP (882±13.3 U/mL) was obtained from white rot fungal strain G. lucidum in solid state bio-processing of wheat straw under optimized fermentation conditions (moisture, 50%; substrate, 5 g; pH, 5.5; temperature, 30°C; carbon source, 2% fructose; nitrogen source, 0.02% yeast extract; C: N ratio, 25:1; fungal spore suspension, 5 mL and fermentation time period, 4 days). After ammonium sulfate fractionation and Sephadex-G-100 gel filtration chromatography, MnP was 4.7-fold purified with specific activity of 892.9 U/mg. G. lucidum MnP was monomeric protein as evident by single band corresponding to 48 kDa on native and denaturing SDS-PAGE. The purified MnP (2 mg/mL) was immobilized using a sol–gel matrix of tetramethoxysilane (TMOS) and proplytrimethoxysilane (PTMS). The oxidation of MnSO4 for up to 10 uninterrupted cycles demonstrated the stability and reusability of the immobilized MnP. Shelf life profile revealed that enzyme may be stored for up to 60 days at 25°C without losing much of its activity. To explore the industrial applicability of MnP produced by G. lucidum, the immobilized MnP was tested against different textile effluents. After 4 h reaction time, the industrial effluents were decolorized to different extents (with a maximum of 99.2%). The maximally decolorized effluent was analyzed for formaldehyde and nitroamines and results showed that the toxicity parameters were below the permissible limits.
In conclusion, G. lucidum MnP was immobilized by sol–gel matrix entrapment with an objective to enhance its practical efficiencies. The MnP was successfully entrapped into a sol- gel matrix of TMOS and PTMS with an overall immobilization efficiency of 93.7%. The sol- gel entrapped MnP seems to have prospective capabilities which can be useful for industrial purposes, especially for bioremediation of industrial effluents.
PMCID: PMC3717284  PMID: 23849469
Bio-catalysis; G. lucidum; MnP; PAGE; Sol–gel; Immobilization; Textile effluents; Decolorization; Toxicity reduction
4.  Improvement of Catalytic Efficiency, Thermo-stability and Dye Decolorization Capability of Pleurotus ostreatus IBL-02 laccase by Hydrophobic Sol Gel Entrapment 
In serious consideration of the worldwide environmental issues associated with the extensive use of the textile dyes and effluents generated thereof, the scientists across the world are in search for potential treatment technologies for their treatment. In such scenario the ligninolytic enzymes provide a potential alternative because they are cost effective, eco-friendly and can be applied to wide range of dye containing industrial effluents.
Laccase produced from Pleurotus ostreatus IBL-02 during decolorization of the reactive textile dye Drimarene brilliant red K-4BL (DBR K-4BL) was purified and immobilized by hydrophobic gel entrapment. The crude laccase was 4.2-fold purified with specific activity of 573.52 U/mg after passing through the DEAE-Sepharose ion exchange and Sephadex-G-100 chromatography columns. P. ostreatus IBL-02 laccase was found to be a homogenous monomeric protein as evident by single band corresponding to 67 kDa on native and sodium dodesylsulfate polyacrylamide gel electrophoresis (PAGE). The laccase was immobilized by entrapment in Sol–gel matrix of trimethoxysilane (T) and proplytetramethoxysilane (P) prepared using different T:P molar ratios. The free and immobilized laccases were compared to investigate the effect of immobilization on catalytic efficiency and thermo-stability features. Laccase immobilized in the Sol–gel of 1:5 T:P ratio was optimally active and thermo-stable fraction at pH 5, 60°C with half-life of 3 h and 50 min. Laccases immobilized in 1:2 and 1:5 T:P ratio gels had significantly higher Km (83 and100mM) and Vmax (1000 and 1111 mM/mg) values as compared to free laccase. After 5 h reaction time varying decolorization percentages with a maximum of 100% were achieved for different dyes and effluents.
In summary, P. ostreatus IBL-02 laccase was immobilized by entrapping in a Sol–gel matrix with an objective to enhance its catalytic and stability properties. Sol–gel entrapped laccase presented potential efficiency as a biocatalyst when applied for decolorization of different dyes and effluents. The main benefits of the Sol–gel matrix immobilization processes are the eco-friendly approach, chemical free and energy saving reaction conditions.
PMCID: PMC3541985  PMID: 23021344
P. ostreatus IBL-02; Laccase; PAGE; Sol–gel immobilization; Kinetics; Textile dye; Waste water effluent; Decolorization
5.  Characterization of purified and Xerogel immobilized Novel Lignin Peroxidase produced from Trametes versicolor IBL-04 using solid state medium of Corncobs 
BMC Biotechnology  2012;12:46.
Cost-effective production of industrially important enzymes is a key for their successful exploitation on industrial scale. Keeping in view the extensive industrial applications of lignin peroxidase (LiP), this study was performed to purify and characterize the LiP from an indigenous strain of Trametes versicolor IBL-04. Xerogel matrix enzyme immobilization technique was applied to improve the kinetic and thermo-stability characteristics of LiP to fulfil the requirements of the modern enzyme consumer sector of biotechnology.
A novel LiP was isolated from an indigenous T. versicolor IBL-04 strain. T. versicolor IBL-04 was cultured in solid state fermentation (SSF) medium of corn cobs and maximum LiP activity of 592 ± 6 U/mL was recorded after five days of incubation under optimum culture conditions. The crude LiP was 3.3-fold purified with specific activity of 553 U/mg after passing through the DEAE-cellulose and Sephadex-G-100 chromatography columns. The purified LiP exhibited a relatively low molecular weight (30 kDa) homogenous single band on native and SDS-PAGE. The LiP was immobilized by entrapping in xerogel matrix of trimethoxysilane (TMOS) and proplytetramethoxysilane (PTMS) and maximum immobilization efficiency of 88.6% was achieved. The free and immobilized LiPs were characterized and the results showed that the free and immobilized LiPs had optimum pH 6 and 5 while optimum temperatures were 60°C and 80°C, respectively. Immobilization was found to enhance the activity and thermo-stability potential of LiP significantly and immobilized LiP remained stable over broad pH and temperature range as compare to free enzyme. Kinetic constants Km and Vmax were 70 and 56 μM and 588 and 417 U/mg for the free and immobilized LiPs, respectively. Activity of this novel extra thermo-stable LiP was stimulated to variable extents by Cu2+, Mn2+ and Fe2+ whereas, Cystein, EDTA and Ag+ showed inhibitory effects.
The indigenously isolated white rot fungal strain T. versicolor IBL-04 showed tremendous potential for LiP synthesis in SSF of corncobs in high titters (592 U/mL) than other reported Trametes (Coriolus, Polyporus) species. The results obtained after dual phase characterization suggested xerogel matrix entrapment a promising tool for enzyme immobilization, hyper-activation and stabilization against high temperature and inactivating agents. The pH and temperature optima, extra thermo-stability features and kinetic characteristics of this novel LiP of T. versicolor IBL-04 make it a versatile enzyme for various industrial and biotechnological applications.
PMCID: PMC3442999  PMID: 22862820
T. versicolor IBL-04; LiP; Immobilization; Xerogel; Characterization; Hyper-activation; Thermo-stabilization; Inactivation tolerance

Results 1-5 (5)