Laccase Enzyme Research Articles

A Comparison of Physical, Chemical, Biological and Combined Treatments for Detoxification of Free Gossypol in Crushed Whole Cottonseed

Oilseed plants such as cotton (Gossypium sp.) generate abundant biomass residues which contain significant levels of edible oil, crude proteins and other desirable biomolecules for the animal nutrition industry. The application of cottonseed cake in animal feed, a by-product of the cotton industry, is limited due to the natural presence of toxic free gossypol (FG), wherein efficient and cost-effective methods for FG detoxification are necessary. Herein, pretreatment methods for reducing FG in crushed whole cottonseed (CWCS) were compared, with residual FG quantified using a sensitive Ultra High-Performance Liquid Chromatography method for detection at trace levels in cottonseed materials. Physical treatment by autoclaving resulted in up to 96% detoxification of FG, without reduction in crude protein (CP) content. Chemical treatment with 1% and 2% Ca(OH)2 eliminated FG to as low as 0.04%, although a reduction in CP content was observed. Similarly, native fermentation, whilst reducing FG content by 99.66% after 6 days incubation, also reduced CP content. In combined physical and biological solid-state fermentation (SSF), basidiomycete fungi Ganoderma lucidum CC351, Panus lecomtei CC40, Pleurotus ostreatus CC389, Pleurotus sapidus CC28 and Pycnoporus sanguineus CC400 all degraded FG in autoclaved CWCS to trace levels often lower than obtained by individual treatments. A reduction in total lipids and increase in CP were also observed, improving nutritional quality. The most efficient fungi, P. ostreatus CC389 and P. lecomtei CC40, secreted considerable laccase and manganese peroxidase enzymes during SSF, potentially involved in FG detoxification. Cost effective, non-polluting, value-adding approaches for FG detoxification offer potential in animal feed industries.

Kinetic characterization of purified laccase from Trametes hirsuta: a study on laccase catalyzed biotransformation of 1,4-dioxane.

Laccase is one of the best known biocatalysts which degrade wide varieties of complex molecules that are both non-cyclic and cyclic in structure. The study focused on enzyme kinetics of a purified laccase from Trametes hirsuta L. fungus and its application on biotransformation of a carcinogenic molecule 1,4-dioxane. Laccase was purified from white-rot fungus T. hirsuta L. which showed specific activity of 978.34 U/mg after the purification fold of 54.08. The stable laccase activity (up to 16h) is shown at 4-6 pH and 20-40°C temperature range. The purified enzyme exhibited significant stability for 10 metal ions up to 10mM concentration, except for Fe2+ and Hg2+. The Cu2+ ion induced laccase activity up to 142% higher than the control at 10mM concentration. The laccase enzyme kinetic parameters Km was 20 ± 5µM and 400 ± 60µM, whereas Kcat was 198.29 ± 0.18/s and 80.20 ± 1.59/s for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and guaiacol respectively. The cyclic ether 1,4-dioxane (100ppm) was completely degraded in presence of purified laccase within 2h of incubation and it was confirmed by HPLC and GC analysis. The oxidation reaction was accelerated by 25, 22, 6 and 19% in presence of 1mM syringaldehyde, vanillin, ABTS and guaiacol mediators respectively. In this study, fungal laccase (a natural biocatalyst) based degradation of synthetic chemical 1,4-dioxane was reported for the first time. This method has added advantages over the multiple methods reported earlier being a natural remedy.

Imidazole-rich copper peptides as catalysts in xenobiotic degradation.

Laccases, oxidative copper-enzymes found in fungi and bacteria were used as the basis in the design of nona- and tetrapeptides. Laccases are known to be excellent catalysts for the degradation of phenolic xenobiotic waste. However, since solvent extraction of laccases is environmentally-unfriendly and yields obtained are low, they are less preferred compared to synthetic catalysts. The histidine rich peptides were designed based on the active site of laccase extracted from Trametes versicolor through RCSB Protein Data Bank, LOMETS and PyMol software. The peptides were synthesized using Fmoc-solid phase peptide synthesis (SPPS) with 30–40% yield. These peptides were purified and characterized using LC-MS (purities >75%), FTIR and NMR spectroscopy. Synthesized copper(II)-peptides were crystallized and then analyzed spectroscopically. Their structures were elucidated using 1D and 2D NMR. Standards (o,m,p-cresol, 2,4-dichlorophenol) catalysed using laccase from Trametes versicolor (0.66 U/mg) were screened under different temperatures and stirring rate conditions. After optimizing the degradation of the standards with the best reaction conditions reported herein, medications with phenolic and aromatic structures such as ibuprofen, paracetamol (acetaminophen), salbutamol, erythromycin and insulin were screened using laccase (positive control), apo-peptides and copper-peptides. Their activities evaluated using GC-MS, were compared with those of peptide and copper-peptide catalysts. The tetrapeptide was found to have the higher degradation activity towards salbutamol (96.8%) compared with laccase at 42.8%. Ibuprofen (35.1%), salbutamol (52.9%) and erythromycin (49.7%) were reported to have the highest degradation activities using Cu-tetrapeptide as catalyst when compared with the other medications. Consequently, o-cresol (84%) was oxidized by Tp-Cu while the apo-peptides failed to oxidize the cresols. Copper(II)-peptides were observed to have higher catalytic activity compared to their parent peptides and the enzyme laccase for xenobiotic degradation.

High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification

Lignin has enabled plants to colonize land, grow tall, transport water within their bodies, and protect themselves against various stresses. Consequently, this polyphenolic polymer, impregnating cellulosic plant cell walls, is the second most abundant polymer on Earth. Yet, despite its great physiological, ecological, and economical importance, our knowledge of lignin biosynthesis in vivo, especially the polymerization steps within the cell wall, remains vague-specifically, the respective roles of the two polymerizing enzymes classes, laccases and peroxidases. One reason for this lies in the very high numbers of laccases and peroxidases encoded by 17 and 73 homologous genes, respectively, in Arabidopsis Here, we have focused on a specific lignin structure, the ring-like Casparian strips (CSs) within the root endodermis. By reducing candidate numbers using cellular resolution expression and localization data and by boosting stacking of mutants using CRISPR-Cas9, we mutated the majority of laccases in Arabidopsis in a nonuple mutant-essentially abolishing laccases with detectable endodermal expression. Yet, we were unable to detect even slight defects in CS formation. By contrast, we were able to induce a complete absence of CS formation in a quintuple peroxidase mutant. Our findings are in stark contrast to the strong requirement of xylem vessels for laccase action and indicate that lignin in different cell types can be polymerized in very distinct ways. We speculate that cells lignify differently depending on whether lignin is localized or ubiquitous and whether cells stay alive during and after lignification, as well as the composition of the cell wall.

Feed-additive of bioengineering strain with surface-displayed laccase degrades sulfadiazine in broiler manure and maintains intestinal flora structure

Sulfonamide antibiotics (SAs) are excreted into the ecosystem unchanged through feces and urine because of their low adsorption and degradation in the guts of humans and animals. In this study, a novel whole-cell biocatalyst with fungal laccase on the cell surface of Escherichia coli Nissle 1917 was developed to degrade sulfadiazine (SDZ). Engineered strain EcN-IL showed laccase enzyme activity of 2 ± 1 U/mg dry weight of cell and degraded 37 ± 1% of SDZ at temperature 40 °C and pH 5 within 3 h in vitro. Strain EcN-IL with 500 mg/kg of SDZ was employed as a food supplement to feed chicken broilers, which can reduce the residue of SDZ in broiler manure by 58 ± 2% and also reduced dysbiosis of the gut microbiota due to overuse of antibiotics. The genetically engineered EcN-IL has laid a foundation for degrading SDZ in broilers and their manure.

Comparative Optimization of Cellulase and Laccase Enzymes in Deinking Process of Used Newspapers

The use of enzymes in the bio-deinking process of newspaper waste has promising potential. However, investigations on the concentration of enzyme combinations need to be carried out to obtain the optimum ratio of cellulase and laccase enzymes for the bio-deinking process of recycled newspapers. The mixture of the two enzymes at various ratios was used to remove the ink on paper pulp from used newspapers by mechanical disintegration method treatment and followed by the bio-deinking process in an incubator shaker. The characterization of functional groups, structures, and thermal properties of bio-deinked pulp paper was carried out by FTIR, XRD, DTG/TGA, and an analysis of the degree of brightness to the prepared paper. FTIR results confirmed three main components of papers, such as cellulose, hemicellulose, and lignin. The XRD results showed that the equal ratio of cellulase and laccase enzymes had an effect on a higher crystallinity index, which was 78.8% compared to those obtained from the conventional methods with a crystallinity index of 69.7%. Thermal analysis showed that the optimum combination of both enzymes contributed the most at the highest temperature where the rate of degradation decreased. Brightness analysis showed that bio-deinking had met the quality requirements for newsprint paper in SNI 7273:2008. Our findings show that the combination of cellulase and laccase enzymes at the same ratio can produce optimal bio-deinked pulp for paper fabrication with excellent characteristics in brightness, thermal, and physical properties.

Optimization of culture conditions for hyper-production of laccase from an indigenous litter dwelling fungus Mucor circinelloides GL1

Fungal laccase is a robust enzyme with broad specificity and applicability in industrial processes. The successful use of enzymes requires large scale production within a short time. As laccase production is highly dependent on medium components and cultural conditions, the optimization of the same is essential for enhancement of its production efficiency. The objectives of present study were to screen litter dwelling fungi for their laccase production and optimize the culture conditions for hyper-production of laccase. A total of 58 fungal isolates were procured from 25 litter samples of plant origin collected from the Western Ghats of Karnataka, India. Among these, five including Mucor circinelloides GL1, Fusarium oxysporum GL2, F. oxysporum GL3, F. verticillioides GL5 and Ceriporiopsis sp. PA1 were selected for optimization studies based on their laccase producing ability. Maximum production was noticed in the optimized culture media and conditions compared to minimal media. Enhanced laccase production was observed by incubating them in optimized media at 28 °C for 8 days at 150 rpm. The laccase enzyme was purified from M. circinelloides GL1 using series of purification steps. The purified enzyme was a monomeric protein band with an apparent molecular weight of about 40 kDa. The present study reported that an indigenous litter dwelling fungus M. circinelloides GL1 found to be efficacious laccase producer in comparison to other isolates tested in this study. Therefore, it can further be utilized as a better biocatalyst in pertinent biotechnological applications.

Kinetic and thermodynamic studies for evaluation of adsorption capacity of fungal dead biomass for direct dye

Abstract This study focuses on evaluation of degradation aptitude of white rot fungus (Coriolus versicolor) against Indosol Turquoise FBL dye. The outcome of numerous parameters including pH, temperature, carbon sources, nitrogen sources, C/N ratio and effect of dye concentration were studied. Maximum decolorization (99.896%) of Indosol Turquoise FBL was obtained by C. versicolor under optimized conditions. After three days, the maximum dye degradation (98%) was observed at pH 4 and 30 °C. Six carbon sources fructose, glucose, maltose, sucrose, rice bran and wheat bran were used and 96.66% degradation was observed by maltose at its optimum growth concentration (0.1 g/100 mL). Various nitrogen sources were employed for decolorization but ammonium nitrate decolorized dye up to 98.05%. The activity of three different enzymes laccase, Lignin peroxidase (LiP) and Manganese peroxidase (MnP) were calculated. The dead biomass of White rot fungus (WRF) was used for biosorption experiments. Maximum q (36 mg/g) was obtained at pH 2, at 30 °C using 0.05 g biosorbent. An increase in the q value was observed with increase in dye concentration. Freundlich adsorption isotherm and pseudo second order kinetics were followed by the data. It can be concluded that C. versicolor could be an efficient source for degradation of dyes from industrial effluents.

Construction of amperometric biosensor modified with conducting polymer/carbon dots for the analysis of catechol

AbstractPhenolic compounds used in food industries and pesticide industry, are environmentally toxic and pollute the rivers and ground water. For that reason, detection of phenolic compounds such as catechol by using simple, efficient and cost‐effective devices have been becoming increasingly popular. In this study, a suitable and a novel matrix was composed using a novel conjugated polymer, namely poly[1‐(5‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophen‐2‐yl)furan‐2‐yl)‐5‐(2‐ethylhexyl)‐3‐(furan‐2‐yl)‐4H thieno[3,4‐c]pyrrole‐4,6(5H)‐dione] (PFTBDT) and carbon dots (CDs) to detect catechol. PFTBDT and CDs were synthesized and the optoelectronic properties of PFTBDT were investigated via electrochemical and spectroelectrochemical studies. Laccase enzyme was immobilized onto the constructed film matrix on the graphite electrode. The proposed biosensor was found to have a low detection limit (1.23 μM) and a high sensitivity (737.44 μA/mM.cm−2) with a linear range of 1.25–175 μM. Finally, the applicability of the proposed enzymatic biosensor was evaluated in a tap water sample and a satisfactory recovery (96–104%) was obtained for catechol determination.

Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites

Natural fibres have a high potential as reinforcement of polymer matrices, as they combine a high specific strength and modulus with sustainable production and reasonable prices. Modifying the fibre surface is a common method to increase the adhesion and thereby enhance the mechanical properties of composites. In this study, a novel sustainable surface treatment is presented: the fungal enzyme laccase was utilised with the aim of covalently binding the coupling agent dopamine to flax fibre surfaces. The goal is to improve the interfacial strength towards an epoxy matrix. SEM and AFM micrographs showed that the modification changes the surface morphology, indicating a deposition of dopamine on the surface. Fibre tensile tests, which were performed to check whether the fibre structure was damaged during the treatment, showed that no decrease in tensile strength or modulus occurred. Single fibre pullout tests showed a 30% increase in interfacial shear strength (IFSS) due to the laccase-mediated bonding of the coupling agent dopamine. These results demonstrate that a laccase + dopamine treatment modifies flax fibres sustainably and increases the interfacial strength towards epoxy.

Novel bacterial biofilm consortia that degrade and detoxify the carcinogenic diazo dye Congo red.

Free-living planktonic single bacterial strain can decolorize Congo red (CR) but often produces the carcinogenic, mutagenic and genotoxic aromatic amines. Planktonic single and bacterial consortia are more susceptible to toxic pollutants than their biofilm counterparts. In the present study, four biofilm consortia (C1 = Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304, C2 = Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201, C3 = E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401, and C4 = E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were prepared and assessed for bioremediation of CR. All these biofilm consortia remarkably decolorized (96.9 to 99.5%) the CR (100mg/L) in static condition within 72h incubation at 28°C. These consortia also synthesized significantly more intracellular azoreductase and laccase enzyme than extracellular of these enzymes. UV-Vis spectral analysis revealed that the major peak at 478nm wavelength of CR was completely disappeared. FTIR analysis showed several major peaks along with azo bonds are completely or partly disappeared, deformed or widened. Chemical oxygen demand was reduced by 86.4, 85.5, 87.0 and 86.2% by C1, C2, C3 and C4, respectively. Accordingly, biodegraded metabolites of CR by different biofilm consortia did not inhibit the germination of wheat seeds and bacterial growth. Thus, these biofilm consortia can be applied in bioremediation of wastewater containing CR for safe disposal into the environment. To our knowledge, this is the first report on degradation and detoxification of aqueous solution containing CR by bacterial biofilm consortia.

Screening for Potential Laccase Producers from Trichoderma Strains Isolated From Riau Citrus Rhizosphere and Palm Tree Plant Parts

The enzyme laccase has wide biotechnology applications in the textile, pulp, food and pharmaceutical industry. Fungal laccases have higher redox potential than bacterial laccases, therefore are more preferred for industry. This study aimed to screen for potential laccase producers from several Trichoderma strains isolated from citrus rhizosphere and as endophytes of palm trees. Four strains were initially screened in a qualitative colour assay on PDA supplemented with substrate indicators of laccase. The qualitative assay showed that Trichoderma asperelloides LBKURCC2 demonstrated strong laccase activity on PDA supplemented with guaiacol or 2,2’-azino-di-3-ethylbenzotiazol-6-sulfonate (ABTS). Trichoderma virens LBKURCC70, 71 and 85 showed very week laccase activity on media supplemented with guaiacol, and no detectable laccase on media supplemented with ABTS. Quantitative assays for laccase activity were performed on crude enzyme extracts from solid state fermentation systems with rice straw as the laccase inducer, and the test fungal strain as the prospective producer. From the quantitative assays it was found that T. asperelloides LBKURCC2 produced the highest laccase activity (208 ± 76 U/L). Laccase activity produced by T. virens LBKURCC70 was 19 ± 5 U/L, while there were no detectable laccase activities produced by T. virens LBKURCC71 and 85.

Combined Microbial Consortium Inoculation and Black Locust Planting Is Effective in the Bioremediation of Waste Drill Cuttings.

Waste drill cuttings (WDCs), produced during gas and oil drilling consisting of 80% rock cuttings and 20% drilling muds, are an increasingly potent source of environmental pollution. We studied the efficiency of bioaugmentation and phytoremediation to remediate WDCs in an experiment where WDCs were incubated in a greenhouse for 120 days with and without black locust (Robinia pseudoacacia) plant and with or without bacterial and fungal consortium inoculant. The pollutant removal rates were highest in inoculated and planted treatment, followed by inoculated treatment and planted treatment. The small decrease in contaminant level in the control treatment suggested that indigenous microorganisms in WDCs had little pollutant degradation capability. In the inoculated and planted treatments, after 120 days, the germination rate of red clover seeds was on the same level as in the natural soil, showing a marked decrease in the ecotoxicity of WDC. Both the bacterial and fungal richness and bacterial diversity increased in all the treatments over time, whereas fungal diversity increased only in the not-inoculated treatments. The activity of laccase enzyme played a key role in the bioremediation process. The enzyme activities were mostly governed by inoculated consortium and soil bacterial community, and black locust affected the bioremediation mainly through its effect on N content that further affected bacterial and fungal communities.

In situ growth of hybrid nanoflowers on activated carbon fibers as electrodes for mediatorless enzymatic biofuel cells

Hybrid nanoflowers (HnFs) are novel structures that comprise enzymes (laccase, glucose oxidase, or catalase) and Cu3(PO4)2-based crystals, which can directly in situ grow on activated carbon fibers (ACFs) for the preparation of electrodes (HnF/ACF) used in glucose biofuel cells. The HnF/ACF structures perform higher enzymatic activities (~4 times) and stability (~2 times) than the enzymes physically adsorbed on ACFs in distinct analyses such as epinephrine oxidation, H2O2 decomposition, and glucose oxidation. The power density of an HnF/ACF-based cell (50 µW cm−2 for a glucose concentration of 50 mM) is 3–5 times higher than that of a cell prepared from conventional enzyme immobilization routes, which can be sustained at up to 80% after one month of operation.

Laccase Affects the Rate of Cryptococcus neoformans Nonlytic Exocytosis from Macrophages.

Nonlytic exocytosis is a process in which previously ingested microbes are expelled from host phagocytes with the concomitant survival of both cell types. This process has been observed in the interaction of Cryptococcus spp. and other fungal cells with phagocytes as distant as mammalian, bird, and fish macrophages and ameboid predators. Despite a great amount of research dedicated to unraveling this process, there are still many questions about its regulation and its final benefits for host or fungal cells. During a study to characterize the virulence attributes of Brazilian clinical isolates of C. neoformans, we observed great variability in their rates of nonlytic exocytosis and noted a correlation between this process and fungal melanin production/laccase activity. Flow cytometry experiments using melanized cells, nonmelanized cells, and lac1Δ mutants revealed that laccase has a role in the process of nonlytic exocytosis that seems to be independent of melanin production. These results identify a role for laccase in virulence, independent of its role in pigment production, that represents a new variable in the regulation of nonlytic exocytosis.IMPORTANCECryptococcus neoformans is a yeast that causes severe disease, primarily in immunosuppressed people. It has many attributes that allow it to survive and cause disease, such as a polysaccharide capsule and the dark pigment melanin produced by the laccase enzyme. Upon infection, the yeast is ingested by cells called macrophages, whose function is to kill them. Instead, these fungal cells can exit from macrophages in a process called nonlytic exocytosis. We know that this process is controlled by both host and fungal factors, only some of which are known. As part of an ongoing study, we observed that C. neoformans isolates that produce melanin faster are more-frequent targets of nonlytic exocytosis. Further experiments showed that this is probably due to higher production of laccase, because fungi lacking this enzyme are nonlytically exocytosed less often. This shows that laccase is an important signal/regulator of nonlytic exocytosis of C. neoformans from macrophages.

Effect of Pleurotus ostreatus and Trametes versicolor on triclosan biodegradation and activity of laccase and manganese peroxidase enzymes

IntroductionTriclosan (TCS) is an extensively used antibacterial agent which has been frequently detected in different environmental compartments. Because of TCS inhibition effect on vast majority of bacterial species, it is important to explore fungal species and their involved enzymes in TCS biodegradation. The aim of this study was to compare the potential of two white rot fungi Pleurotus ostreatus and Trametes versicolor for TCS biodegradation through the whole cell culture of fungi in an aqueous culture medium. Additionally, the changes in ligninolytic enzyme activities and possible correlations and contributions of degradative enzymes during TCS biodegradation process were monitored. Material and methodsThis study was carried out using a factorial experiment with a completely randomized design in three replications. factorial design in The experimental factors included: two white rot fungi Pleurotus ostreatus and Trametes versicolor and uninoculated controls which were subjected to five levels of TCS concentrations (0, 5, 10, 20, 30 and 50 μg mL−1) to assess ligninolytic enzymatic activity during biodegradation of TCS. Samples were harvested periodically at three time intervals (4, 7 and 10 days). An AB SCIEX 3200 QTRAP LC-MS/MS system was used in order to analyze the biodegradation of TCS in liquid medium. ResultsResults suggested that the two white rot fungi responded differently when exposed to the different concentrations of TCS. In general, P. ostreatus exhibited more potential and ligninolytic enzymatic activity compared to T. versicolor. LC-MS/MS analyses also showed that P. ostreatus degraded TCS with higher efficiency compared to T. versicolor. In addition, almost all P. ostreatus biodegradation activity was completed within the first day of sampling. Contrasting, less efficient degradation was observed by T. versicolor, reaching around 88% of TCS biodegradation at concentration of 20 μg mL−1after 10 days. At higher TCS concentrations (≥30 μg mL−1), the growth of T. versicolor severely inhibited and led to a drop in enzymatic activity and biodegradation. Furthermore, laccase and manganese peroxidase (MnP) were determined as more involved enzymes which significantly correlated to TCS biodegradation by T. versicolor and P. ostreatus, respectively. ConclusionP. ostreatus might be considered as efficient fungus in biodegradation of high amount of TCS in environmental matrices. The results of the present study might provide insights for future investigations on potential of fungi for applications in bioaugmentation-based strategies to remove TCS from wastewater and activated sludge.

An innovative co-fungal treatment to poplar bark sawdust for delignification and polyphenol enrichment

This work aims to demonstrate a new high-efficient way to lignin degradation plus polyphenol enrichment in poplar bark sawdust by a co-fungal treatment with white rot fungi of C. subvermispora, C. cinereus and P. ostreatus in an equal volume-ratio fermentation for three weeks. The results indicated that compared with any one of these fungi, over 50 % lignin-degradation and 6-fold polyphenol enrichment were achieved at the 12th day for the best performance by these mixed-fungi treatments. The polyphenol enrichments from the increasing amount of protocatechuic acid and caffeic acid-3-glucoside were confirmed by HPLC-ESI-QTOF-MS/MS and ATR-FT-IR, which facilitated the lignin-degradation in turn. They were potentially ascribed to an obvious improvement activity of ligninolytic enzyme (laccase, lignin peroxidase and manganese-dependent peroxidase) for the lignin-degradation and β-glycosidase action for flavonoid degradation, respectively. All above-mentioned results will provide a potential protocol for lignin degradation and polyphenol enrichment when the different fungi in co-culture play a role in synergism.

SCREENING, ISOLATION, AND PRODUCTION OF FUNGAL LACCASE FROM SAW MILL SOIL OF OSMANABAD.

The rainforest and wood decaying habitats are the main sources for the several laccase producers, which include plant, bacteria, fungi and actinomycetes. Among these, several fungal species having laccase producing ability, which mainly includes wood rooting fungi that are often associated with lignin peroxidase or manganese dependent peroxidase or both. In view of this, we screened the natural habitats like saw mill soil and nearby places of Osmanabad district of Maharashtra for isolation of potential fungal species having laccase producing abilities. A total 45 fungal strains were isolated and screened for laccase production on solid media like Czapak dox agar medium containing guaiacol, tannic acid, bromophenol blue, and ABTS. Out of that 24 isolates showed positive results and among these S19 was found to be a potent laccase producing ability. The S19 fungus sp. subcultured on Czapak dox agar slant and screened for laccase enzyme production on solid state fermentation using wheat bran. In conclusion, we isolated the most potent laccase producing S19 fungus sp. from local natural habitats. A total 11.35 U/L of laccase enzyme obtained under optimized solid state fermentation. The enzyme may find potential applications in degradation of xenobiotics, decolourization of dyes, pulp and paper industries, depolymerisation of lignin, pigment degradation, and several other industrial processes.

Microorganisms in Coal Desulfurization (Review)

The information on the use of microorganisms and mixed consortia in the biological desulfurization of coal is summarized. The ecological problems that accompany the burning of high-sulfur coals are shown, and the prospects of environmentally friendly and resource-saving biotechnological approaches to coal desulfurization are considered. Analysis of available literature indicates the enormous role of microorganisms of various taxonomic groups in the removal of inorganic and organic sulfur in coals. Mesophilic and moderately thermophilic acidophilic chemolithotrophic bacteria (ACB) of the genus Acidithiobacillus—A. ferrooxidans, A. thiooxidans, A. caldus, as well as some heterotrophic bacteria Bacillus subtilis and paenibacillus polymyxa—play the dominant role in the removal of inorganic sulfur. Mixed cultures and associations of mesophilic and thermophilic bacteria isolated from coal mines or from the coal surface structure are considered an effective tool in the biosulfurization of pyrite sulfur. The prospects of microbial desulfurization of organic coal sulfur with the use of heterotrophic microorganisms of the genera Pseudomonas, Sulfolobus, Rhodococcus, the fungi Agrocybe aegerita and Alterneria sp., the bacterial–fungal consortia Sulfolobus solfataricus and Phanerochaeta chrysosporium ME446, and the laccase enzyme of the basidiomycetes Trametes versicolor ATCC 20080 are examined.

Sustainable, Site-Specific Linkage of Antimicrobial Peptides to Cotton Textiles.

A new general method to covalently link a peptide to cotton via thiazolidine ring formation is developed. Three different analogues of an ultrashort antibacterial peptide are synthesized to create an antibacterial fabric. The chemical ligation approach to the heterogeneous phase made up of insoluble cellulose fibers and a peptide solution in water is adapted. The selective click reaction occurs between an N-terminal cysteine on the peptide and an aldehyde on the cotton matrix. The aldehyde is generated on the primary alcohol of glucose by means of the enzyme laccase and the cocatalyst 2,2,6,6-tetramethylpiperidine-1-oxyl. This keeps the pyranose rings intact and may bring a benefit to the mechanical properties of the fabric. The presence of the peptide on cotton is demonstrated through instant colorimetric tests, UV spectroscopy, IR spectroscopy, and X-ray photoelectron spectroscopy analysis. The antibacterial activity of the peptides is maintained even after their covalent attachment to cotton fibers.