High Yield Research Articles

Polyoxometalate-Based Single-Atom Catalyst with Precise Structure and Extremely Exposed Active Site for Efficient H2 Evolution.

Single-atom catalysts with precise structure and extremely high catalytic efficiency remain a fervent focus in the fields of materials chemistry and catalytic science. Herein, a nickel-substituted polyoxometalate (POM) {NiSb6O4(H2O)3[β-Ni(hmta)SbW8O31]3}15- (NiPOM) with one extremely exposed nickel site [NiO3(H2O)3] was synthesized using the conventional aqueous method. The uniform dispersion of single nickel center with well-defined structure was facilely achieved by anchoring nanosized NiPOM on graphene oxide (GO). The resulting NiPOM/GO can couple with CdS photoabsorber for the construction of low-cost and ultra-efficient hydrogen evolution system. The H2 yield can reach to 2753.27 mmol gPOM -1 h-1, which represents a record value among all the POM-based photocatalytic systems. Remarkablely, an extremely high hydrogen yield of 3647.28 mmol gPOM -1 h-1 was achieved with simultaneous photooxidation of commercial waste plastic, representing the first POM-based photocatalytic system for H2 evolution and waste plastic conversion. This work highlights a straightforward strategy for constructing extremely exposed single-metal site with precise microenvironment by facilely manipulating nanosized molecular cluster to control individual atom.

Fabrication, Microstructural Evolution, and Mechanical Properties of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C Nanocomposites

A dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C high-entropy ceramic nanocomposite was prepared using a polymer-derived ceramic (PDC) method combined with spark plasma sintering (SPS). The microstructural evolution and mechanical properties of the obtained nanocomposites were characterized by X-ray diffractometer (XRD), transmission electron microscope (TEM), scanning-electron microscope (SEM), and nanoindentation. The results indicate that the phase composition of SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C can be adjusted by modifying the metal content of the single-source precursor (SSP) through molecular design. The resulting precursor exhibits an exceptionally high ceramic yield, with mass retention of over 90% at 1100 °C, which guarantees the densification of the final SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C composites. The PDC route facilitates the in situ formation of a high-entropy phase within the ceramic matrix under low temperature pyrolysis conditions. Combined with SPS, a dense monolithic SiC/(Hf0.25Ta0.25Zr0.25Nb0.25)C/C nanocomposite was obtained, exhibiting an open porosity of 0.41 vol%, nano-hardness of 27.47 ± 0.46 GPa, elastic modulus of 324.00 ± 13.60 GPa, and fracture toughness of 3.59 ± 0.24 MPa·m0.5, demonstrating excellent mechanical properties.

Nanodomain-Enhanced Stable and Multifunctional Probes with Near 100% Quantum Yield for Versatile Biosensing.

The preparation of high quantum yield, stable, and multifunctional fluorescent probes is of great significance in the fields of biomedicine and photoelectric sensing. Here, a triphenylamine-based D-π-A fluorescent molecule (TPA-CN) was designed and prepared, demonstrating a fluorescence quantum yield of 88.84%. With a polystyrene nanosphere as the carrier, TPA-CN was encapsulated inside the nanosphere to form intra-nanosphere confining domains. These nanodomain-enhanced fluorescent nanospheres exhibited a fluorescence quantum yield of 98.21%. Using antigen-antibody specificity and the selective catalytic activity of a bioenzyme, with chloramphenicol as a model target, a dual-signal readout biosensor (in fluorescence and colorimetric modes) was designed for ultrasensitive and instrument-free determination. The detection limit was 24 pg/mL within 30 min in fluorescence mode, 38-fold more sensitive and 10-fold faster than that of enzyme linked immunosorbent assays. The nanodomain-enhanced fluorescent probes and dynamic biosensor provide a robust and versatile solution for public health and environmental monitoring needs.

Assessment of Water-Related Ecosystem Services and Beneficiaries in the Hainan Tropical Rainforest National Park

Tropical rainforests are of vital importance to the environment, as they contribute to weather patterns, biodiversity and even human wellbeing. Hence, in the face of tropical deforestation, it becomes exigent to quantify and assess the contribution of ecosystem services associated with tropical rainforests to the environment and especially to the people. This study adopted a nuanced approach, different from traditional economic valuations, to estimate the water-related ecosystem services (WRESs) received by the people from 2010 to 2020 in the Hainan Tropical Rainforest National Park (HTRNP). The study focused on water yield, soil conservation, and water purification using InVEST, the SCS-CNGIS model, and spatial analysis. The results show (1) significant land cover changes within the HTRNP, as forest decreased by 4433 ha and water bodies increased by 4047 ha, indicating the active presence of human activities. However, land cover changes were more pronounced within the 5 km buffer area around the HTRNP, suggesting the effectiveness of the tropical rainforest conservation efforts in place. (2) The water yield of the HTRNP in the years studied decreased by 307.03 km3, based on the water yields in 2010 and 2020, which were 5625.7 km3 and 5318.7 km3, respectively. (3) Change detection showed that runoff mitigation in the rainforest has a negative mean (−0.21), indicating a slight overall decrease in soil conservation and runoff mitigation in the rainforest from 2010 to 2020; however, the higher curve number indicates areas susceptible to surface runoff. (4) The ecological effectiveness of water purification to absorb and reduce nitrogen load was better in 2020 (145,529 kg/year), as it was reduced from 506,739 kg/year in 2010, indicating improved water quality. (5) Population growth is more pronounced in areas with high water yields. Overall, the proposed framework has shown that the water yield potential of the HTRNP can meet the water consumption demands of people and industries situated within the buffer area. However, analysis of the study shows that it does not meet the crop water requirements. This study provides insights for decision makers in identifying potential beneficiaries and the essence of effective area-based conservation measures, and the proposed framework can be applied to any area of interest, offering a different approach in ecosystem services assessment.

PHENOTYPIC DIVERSITY OF SWEET POTATO (IPOMOEA BATATAS[L.]LAM.) GERMPLASMUSING QUANTITATIVE TRAITS: A PRE- BREEDING STUDY IN TOGO

Objective: Sweet potato is a root and tuber crop which contribute to food security in Togo. However, little scientific data exists on the genetic variability of cultivars grown in Togo, although this information is a prerequisite for development of new varieties. The objective of this study was to explore the phenotypic diversity within Togos sweet potato cultivars. Materials and Methods: The germplasm is composed of sixty five (65) cultivars from Togo and sixteen (16) exotic varieties introduced from Burkina Faso breeding unit. The experiment was laid out in a 9 x 9 lattice square design with three replicates. In total, sixteen (16) quantitative traits were evaluated using the sweet potato ontology as described by CIP. Results:Descriptive statistics, ANOVA and PCA revealed high variability for traits such as root yield, dry matter content, aboveground biomass, stem length, internode length and stem diameter. Cluster analysis performed on the basis of the Euclidean distance between cultivars using Ward method as aggregation criterion has revealed four phenotypic clusters. Clusters I and II are composed of varieties with low root yield (12.95 and 15.87 t.ha-1) and high dry matter content (29.68 and 26.86%). Clusters III and IV are made of varieties exhibiting high aboveground biomass (37.74 and 50.75 t.ha-1), high fresh root yield (16.06 and 20.18 t.ha-1) and low dry matter content (24.62 and 23.84%). The variability observed in this gene bank constitutes a basis for genetic improvement programmes of sweet potato in Togo.

Calcination-Controlled Synthesis of Carbon Dots@MgF2 Composites with Yellow, White, and Ultraviolet-Blue Thermally Activated Delayed Fluorescence for Multilevel Information Encryption.

It is attractive but challenging to develop carbon dot (CD) based materials with tunable thermally activated delayed fluorescence (TADF), especially in the long wavelength region. Here, by simply calcinating the mixture of m-phenylenediamine and MgF2 at 300-500 °C, a series of CDs@MgF2 composites exhibiting yellow, white, and ultraviolet-blue TADF with high photoluminescence quantum yields of up to 37.6% are prepared. Photophysical studies reveal that the yellow TADF with long lifetimes of 810-1106ms originates from the surface emission centers of CDs, while the ultraviolet-blue TADF with short lifetimes of 266-379ms is related to the carbon core emission centers. The combination of yellow and ultraviolet-blue TADF in a single material triggers dynamic afterglow with time-dependent colors from white to yellow. The MgF2 matrix offers multiple confinement of CDs through a rigid network, strong space constraint, and robust covalent/hydrogen bonding, thus preventing the triplet excitations from non-radiative transitions. The electron-withdrawing fluorine atoms induce substantial spin-orbit coupling and reduce the singlet-triplet energy gap, consequently facilitating the reverse intersystem crossing to enhance TADF efficiency. Importantly, the CDs@MgF2 composites possess outstanding optical stability against water, organic solvents, strong acids, bases, and oxidants. The fascinating TADF features enable the successful demonstration of multilevel information encryption using CDs@MgF2.

Unlocking full potential of bamboo waster: Efficient co-production of xylooligosaccharides, lignin, and glucose through low-dosage mandelic acid hydrolysis with alkaline processing

Mandelic acid (MA), a natural and environmentally friendly organic acid, demonstrates high selectivity and efficiency in hydrolyzing hemicellulose, making it an excellent candidate for xylooligosaccharides (XOS) production at low acid dosages. Despite its potential, the application of MA for XOS production has not been evaluated. The study first investigated the effectiveness of MA in hydrolyzing hemicellulose in bamboo into XOS. Under optimized conditions (50 mM MA, 180 °C, 45 min), a high XOS yield of 65.9 % was achieved, with a total xylobiose and xylotriose yield of 43.5 %. Subsequent alkaline pretreatment enabled 92.1 % lignin removal from MA-pretreated bamboo. The recovered lignin exhibited a high purity of 95.2 % and retained fundamental structure and functional groups of native lignin. The resulting residue displayed enhanced crystallinity and accessibility, with reduced hydrophobicity and surface area lignin compared to untreated bamboo. At high substrate concentration of 20 %, cellulase hydrolysis resulted in a glucose conversion efficiency of 83.9 %. Overall, this integrated strategy offered an efficient approach for the co-production of valuable XOS, lignin, and glucose from bamboo. The efficient energy utilization and economic viability further highlight the potential of this method for large-scale industrial applications, making it an attractive option for biomass valorization.

Photo-Induced Three-Component Reaction for the Construction Of α-Tertiary Amino Acid Derivatives.

The synthesis of α-tertiary amino acids (ATAAs), which are pivotal components in natural metabolism and pharmaceutical innovation, continues to attract significant research interest. Despite substantial advancements, the pursuit of a facile, versatile, and resource-efficient methodology remains an area of active development. In this work, we introduce a visible light-triggered three-component reaction involving readily available nitrosoarenes, N-acyl pyrazoles, and allyl or (bromomethyl)benzenes under mild conditions. This approach enables the straightforward assembly of a wide array of ATAA derivatives (42 examples) in commendably high yields (up to 89 %). Mechanistic investigations elucidate that the reaction proceeds through a dehydration condensation between nitrosoarenes and N-acyl pyrazoles to generate ketimine intermediates. This is followed by a light-driven halogen atom transfer (XAT) process and a radical addition, culminating in the formation of the desired products. The approach showcases excellent functional group compatibility and late-stage derivatization potential, offering new insights and avenues for the synthesis of ATAA analogs.

Correlations between local chemical fluctuations and grain boundary strength in Ti-Zr-Nb-Ta-Mo refractory multi-principal element alloys

Ti-Zr-Nb-Ta-Mo refractory multi-principal element alloys typically exhibit high yield strength while tensile ductility tends to be poor. In this study, we found that even after solid solution treatment of Ti-Zr-Nb-Ta-Mo alloys, significant change in ductility occur due to the local chemical fluctuations. Ta's dramatic chemical fluctuations cause variations in atomic-scale strain fields, leading to reduced grain boundary strength and brittle fracture. First-principles calculations show that (Ti, Zr)-rich at the grain boundaries increases the delocalization of valence electrons, leading to longer bond lengths and reduced crystal orbital bond index values, thereby causing grain boundary embrittlement. Our findings explore the root causes of brittleness in Ti-Zr-Nb-Ta-Mo alloys at the atomic and electronic scales, providing not only a method to analyze grain boundary embrittlement using bond length, electronic localization function and crystal orbital bond index, but also a theoretical guidance for improving the mechanical properties via grain boundary structure optimization.

Interaction between material and process parameters during 3D concrete extrusion process

Extrusion of cement-based materials in additive manufacturing is influenced by a complex interaction of various material and process parameters. This study aims to investigate the impact of rheological properties and printing parameters on the extrudability of cement-based materials as well as the interaction between rheological properties of print materials and extrusion speed, as a key printing process parameter. 20 different print materials with diverse rheological properties were extruded at 10 different extrusion speeds. The effect of material parameters (i.e. rheological properties) and process parameters (i.e., extrusion speed) and their interaction during the extrusion process were evaluated using filament continuity, conformity and consistency. At a constant printing speed, a higher yield stress adversely impacted filament continuity in mixtures with a yield stress of over 260 Pa, whereas viscosity showed minimal influence on filament quality within the tested range of the rheological properties. The results of this study highlighted a significant correlation between material and process parameters and that adapting process parameters to variations in material properties is crucial for meeting printing criteria. The filament consistency of the mixtures with high yield stress was more sensitive to change in the extrusion speed than that of mixtures with low yield stress. An opposite trend, however, was observed for filament conformity where low yield stress mixtures showed a higher sensitivity to the extrusion speed. A procedure was suggested and applied to determine the optimum extrusion speed. Optimal extrusion speeds enabled printing mixtures with a broader spectrum of rheological properties with an acceptable visual quality, filament conformity and consistency requirements. With extrusion speed adjustment, the extrudability window was expanded from dynamic yield stress of 108–126 Pa to 108–263 Pa and plastic viscosity of 8.2–12.3 Pa.s to 5.1–16.4 Pa.s.

Advanced Extraction Techniques and Physicochemical Properties of Carrageenan from a Novel Kappaphycus alvarezii Cultivar

Carrageenans are valuable marine polysaccharides derived from specific species of red seaweed (Rhodophyta) widely used as thickening and stabilizing agents across various industries. Kappaphycus alvarezii, predominantly cultivated in tropical countries, is the primary source of kappa-carrageenan. Traditional industrial extraction methods involve alkaline treatment for up to three hours followed by heating, which is inefficient and generates substantial waste. Thus, developing improved extraction techniques would be helpful for enhancing efficiency and reducing environmental impacts, solvent costs, energy consumption, and the required processing time. In this study, we explored innovative extraction methods, such as ultrasound-assisted extraction (UAE) and supercritical water extraction (SFE), together with other extraction methods to produce kappa-carrageenan from a new strain of K. alvarezii from the Philippines. FTIR-ATR spectroscopy was employed to characterize the structure of the different carrageenan fractions. We also examined the physicochemical properties of isolated phycocolloids, including viscosity, and the content of fatty acids, proteins, and carbohydrates. For refined carrageenan (RC), both the traditional extraction method and the UAE method used 1 M NaOH. Additionally, UAE (8% KOH) was employed to produce semi-refined carrageenan (SRC). UAE (8% KOH) produced a high yield of carrageenan, in half the extraction time (extraction yield: 76.70 ± 1.44), and improved carrageenan viscosity (658.7 cP), making this technique highly promising for industrial scaling up. On the other hand, SFE also yielded a significant amount of carrageenan, but the resulting product had the lowest viscosity and an acidic pH, posing safety concerns as classified by the EFSA’s re-evaluation of carrageenan as a food additive.

Mechanochemical Synthesis of Carbazole Isomer Phosphors.

The 1H-benzo[f]indole (Bd[f]), a carbazole (Cz) isomer is first reported as the source of Cz-based phosphors in 2020. In this work, the novel carbazole isomers, 1H-benzo[g]indole (Bd[g]) based derivatives, are synthesized by a one-step solvent-free mechanical ball milling reaction, establishing a facile, efficient, and environmentally friendly method for the synthesis of new Cz isomer phosphorescent derivatives with high yields compared to previously reported multi-step solvent-based thermochemical synthesis routes of Bd[f] derivatives with low yields. Six Bd[g] derivatives with different substituents, namely OCH3-Bd, In-Bd, Bn-Bd, F-Bd, Cl-Bd, and Br-Bd, are synthesized, which exhibit distinctly different single-crystal structures and phosphorescent properties. After irradiation with 365nm UV light, Bd[g] derivatives-doped poly (methyl methacrylate) (PMMA) films exhibit photoactivated green room-temperature phosphorescence with ultra-long lifetimes up to 1.65s. Interestingly, the phosphorescence is stable in seawater along with good bactericidal properties, which also provide new candidates for indole-based marine antifoulants. This study demonstrates that mechanical ball milling is an efficient method for the synthesis of benzoindole heterocycles. Bd[g], as new members of the benzoindole family, are new building units to construct carbazole isomer phosphorescent molecules besides Bd[f].

Performance of French Bean Genotypes at Late Season Sowing in Sylhet, Bangladesh

Performance of four French bean genotypes were evaluated at late sowing condition in Randomized Complete Block design with three replications at the experimental field of Sylhet Agricultural University, Bangladesh to assess the yield performance of French bean genotypes under late-season sowing conditions in Sylhet, Bangladesh. Seeds of four French bean genotypes including BARI Jharsheem-1, Jharsheem-2, Jharsheem-3 and Local were sown in the main field at 25 November and 25 December 2022. The highest number of pods per plant was found in the genotype BARI Jharsheem-1 (32.14), which was statistically at par with the genotype BARI Jharsheem-2 (30.46). The lowest number of pods per plant was found in the genotype BARI Jharsheem-3 (20.10) which was closer to local genotypes (21.68). The highest pod yield per plant was found in BARI Jharsheem-1 (194.45 g) and the lowest in BARI Jharsheem-2 (125.62 g) which was statistically similar with the remaining two genotypes. The highest yield per decimal was produced by the genotype BARI Jharsheem-1 (95.04 Kg) but the lowest yield per decimal was produced by BARI Jharsheem-2 (61.41 Kg). Significant variation was found of sowing date on yield and yield attributes of French bean except some parameters. Maximum yield per decimal was produced from 25 December sowing (73.57 Kg) than 25 November sowing (68.09 Kg). However, interaction effect showed appreciable amount of green pods from BARI Jharsheem-1 at 25 November (87.17 kg/decimal) and 25 December sowing (102.91 kg/decimal) indicating bright scope during late winter season. The results conclude that among the genotypes, BARI Jharsheem- 1 had the highest pod yield and yield per decimal. Sowing on December 25 produced higher yields (73.57 kg/decimal) than November 25 (68.09 kg/decimal). These findings suggest the potential to improve French bean yield and market availability during late winter through optimized genotype selection and sowing dates.

Fusarium verticillioides pigment: production, response surface optimization, gamma irradiation and encapsulation studies

BackgroundNatural pigments are becoming more significant because of the rising cost of raw materials, pollution, and the complexity of synthetic pigments. Compared to synthetic pigments, natural pigments exhibit antimicrobial properties and is less allergic. Pigments from microbial sources could easily be obtained in an inexpensive culture media, produced in high yields, and microbes are capable of producing different colored pigments. Searching for new sources for natural pigments to replace synthetic ones in food applications has become an urgent necessity, but the instability of these compounds is sometimes considered one of the obstacles that reduce their application. Encapsulation provides an ideal solution for natural dye protection through a controlled release strategy. Thus, this study aims at isolation of several soil fungi and subsequent screening their pigment production ability. The chosen pigment-producing fungal strain underwent full identification. The produced pigment was extracted with ethyl acetate and estimated spectrophotometrically. As there is a necessity to obtain a high pigment yield for efficient industrial application, the best production medium was tested, optimum conditions for maximum dye production were also investigated through the response surface methodology, and gamma irradiation was also employed to enhance the fungal productivity. Encapsulation of the produced pigment into chitosan microsphere was tested. The pigment release under different pH conditions was also investigated.ResultsA new strain, Fusarium verticillioides AUMC 15934 was chosen and identified for a violet pigment production process. Out of four different media studied, the tested strain grew well on potato dextrose broth medium. Optimum conditions are initial medium pH 8, 25 °C-incubation temperature, and for 15-day incubation period under shaking state. Moreover, a 400 Gy irradiation dose enhanced the pigment production. Chitosan microsphere loaded by the pigment was successfully prepared and characterized by infrared spectroscopy and scanning electron microscopy.ConclusionThis irradiated Fusarium strain provides a more economically favorable source for production of a natural violet dye with an optimum productivity, enhanced yield, and improved properties (such as, enhanced stability, controlled release, and bioaccessibility) by encapsulation with chitosan for efficient application in food industry.

Metal‐ and Additive‐Free One‐Pot Synthesis of 2,3,5‐Trisubstituted 1,3,4‐Thiadiazines Using β‐Ketodithioesters and 2‐Bromohydrazones through a Cross‐Coupling/Cyclization Cascade

AbstractPrivileged 2,3,5‐trisubstituted 1,3,4‐thiadiazines were synthesized from readily accessible β‐ketodithioesters as a two‐atom (CS) synthon and 2‐bromohydrazones as a four‐atom (CCNN) unit through a cross‐coupling/cyclization cascade. The operationally simple metal‐ and additive‐free method shows broad substrate scope as well as high functional‐group tolerance and provides a direct route to functionalized 1,3,4‐thiadiazines that are not easily prepared by other methods. This one‐pot approach features easy‐to‐handle nontoxic reagents, high yields, gram scalability, excellent selectivity and the formation of an exocyclic double bond with Z‐stereoselectivity.

Phenotypic characterization of different seed coat color of cowpea cultivars, Vigna unguiculata (L). Walp. in West-Central Côte d'Ivoire

Cowpea is a widely consumed legume in sub-Saharan Africa. Several cowpea cultivars based on seed coat color are widely observed. Consumers' choice of cultivar varies from one region to another. However, the lack of improved varieties and the limited availability of information on the productive potential of these cultivars is one of the constraints on the development of cowpea production. Thus, red, white, black and brown seed coat widely consumed were evaluated in the field over two consecutive years, 2022 and 2023 on a plot following a randomized complete block design with four replications. Morphological and agronomic parameters showed that there were two groups of cultivars with interesting agronomic characteristics. The first group composed of the black, brown and red cultivars had a relatively short reproductive time, averaging 66 days. These cultivars are considered early. The number of fruits of these cultivars was also high, with an average of 12 fruits per plant. The second group, consisting exclusively of the white seed coat cultivar produced high biomass and plant length. It had also twice the pod and seed weight of the other cultivars. It would be possible to develop hybrids in the future, seeking, for example, to improve the seed weight of the red cultivar with a short reproductive cycle by crossing with the white seed coat cultivar, with a view to creating an early variety with a high yield.

A Novel Approach for the Synthesis of 3,3′-((4-Methoxyphenyl)methylene)bis(4-hydroxyfuran-2(5H)-one) Employing Natural Deep Eutectic Solvents and Microwave Irradiation

Tetronic acid, a five-membered heterocyclic moiety present in various natural products, has emerged as a significant building block for many pharmaceutically active compounds. In this study, a novel protocol for the synthesis of the bis-tetronic acid 3,3′-((4-methoxyphenyl)methylene)bis(4-hydroxyfuran-2(5H)-one) (3) via a domino Knoevenagel–Michael reaction is presented. The natural deep eutectic solvent L-proline/glycerol 1:2 molar ratio was utilized as a solvent and catalyst, while the reaction was further promoted via microwave irradiation, providing the desired product in high yield (83%). The solvent was successfully recycled and reused up to three times.

Improving the Photochemical Skeletal Enlargement of Pyridines to 1,2‐Diazepines with Isocyanates

In this work, we extend the one‐pot protocol to synthesize 1,2‐diazepines from commercially available and cheap starting materials. Capitalizing on isocyanate derivatives as activating agents, the photochemical skeletal enlargement occurs, while preserving key functional groups embedded in more than 30 substrates. We also demonstrated that isocyanates can be generated in situ exploiting the wealth of methods starting from bench stable resources. Compare to previous strategies, the use of these precursors prevents the presence of deleterious HCl traces in the system, thus enabling the synthesis of 1,2‐diazepines in high yields over up to 5 sequential steps.

Nano Fe3O4 catalyzed selective, tandem, and oxidative conversion of alcohols, tetrahydropyranyl and trimethylsilyl ethers to oximes

Tandem and efficient conversion of alcohols, tetrahydropyranyl (THP) and trimethylsilyl (TMS) ethers as protected alcohols to oximes is described using a catalytic amount of nano Fe3O4 as a highly magnetic and nontoxic catalyst, tert-butyl hydroperoxide (TBHP) and hydroxylamine hydrochloride. The nanocatalyst is easily separated from the reaction medium using an external magnet and can be reused for several times without any considerable loss of its catalytic power. Also, it was found that it is possible to perform these oxidative conversions efficiently even in the presence of epoxides, carboxylic acids and esters, phenols, sulfides and pyridine rings with excellent chemoselectivity. The tandem and catalytic nature, catalyst reusability, high yields, and easy work up can be considered as the main advantages of the present environmentally friendly method.

Microbial Pigment Isolation, Culturing, and Extraction to Use as Textile Dyes

The textile industry is one of the largest worldwide polluters of clean water due to the heavy use of synthetic dyes. These chemicals negatively affect the environment, especially aquatic life due to their toxic and mutagenic properties. Synthetic dyes cause harm to human health such as skin allergies and respiratory sensitization. Several advantages such as ease of extraction, availability, high yields and no seasonal variation make microbial pigments the most ideal source of natural pigments. This study was done to isolate colour pigment producing bacteria and fungi from soil collected from organic farms from various locations in Sri Lanka. Out of 7 soil samples, 3 yielded pigment producing bacteria and fungi. In total, 9 pigment producing bacteria and 3 pigment producing fungi were isolated. Gause’s synthetic agar yielded the most pigmented isolates. Isolates were inoculated in broths and pigment production was observed. Extracellular pigments produced by 5 of the bacterial isolates were extracted by a water-based method. The antibacterial activity of the pigments in their crude and concentrated forms was tested using the well diffusion method against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P. Inhibition zone against S. aureus was observed for both crude (12.33±0.58mm) and concentrated pigments (9.67±0.58mm) extracted from purple pigment producing bacterial isolate (BPU). This pigment has the potential to be used in antibacterial textile preparation. Extracted pigments were used to dye scoured cotton fabric with the use of 3% alum as mordant. Pigment from BPU isolate resulted in better coloured fabric.