Microbial pigments are gaining more attention in recent times due to their versatile applications in the pharmaceutical, food, cosmetic, and textile industries. The development of microbial pigments ...is a challenging task due to the presence of inexpensive synthetic dyes in the market. However, the harmful side effects of most of the azo and benzidine synthetic dyes have compelled many scientists and experts to shift their attention to chemically greener routes of dye production. Micro-organisms are endowed with the potential to produce useful natural colorants such as carotenoids on an industrial scale at relatively low costs. This review aims to provide crucial information on the biodiversity, distribution, pathogenicity, ecological and industrial applications of microbial pigments, as well as challenges and future directions for food, textile, pharmaceutical, cosmetic, and biomedical applications. It also highlights the challenges faced by the use and development of food and textile-grade pigments and proposes recommendations to deal with these challenges using advanced techniques, including metabolic engineering and gene editing technologies.
•This review article provides an up-to-date knowledge regarding the biosynthesis of microbial pigments from microorganisms.•The methods to increase the yield of microbial pigment using modern-day technologies have also been reviewed in detail.•This review provides detailed information regrading the applications of microbial pigments in various industries.•This review highlights the challenges faced by the use of food and textile-grade pigments.
Chalcones are well-known natural dyes, 18 different derivatives selected from the rational molecular design (i.e. through molecular orbital calculations) were synthesized. If used in conjunction with ...an amine (i.e. ethyl l, 4-(dimethylamino) benzoate, EDB) and an iodonium salt (bis(4-tert-butylphenyl) iodonium hexafluorophosphate, Iod) as photoinitiating systems (PISs), these dyes can initiate both the free radical polymerization of polyethylene glycol diacrylate (PEG-diacrylate) and the cationic polymerization of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (EPOX) via oxidation–reduction reaction mechanisms. Furthermore, among the 18 different suggested structures, except for dyes 9 and 10, which have been synthesized and used in other fields, the remaining 16 dyes have never been synthesized before. The photopolymerization efficiency of acrylates carried out under LED@405 nm are excellent both for thin films (the thickness is about 0.2 mm) and thick films (the thickness is about 2 mm). Furthermore, all of them can also boost the cationic polymerization of EPOX upon LED irradiation at 405 nm, in the presence of an iodonium salt and an amine. More interestingly, stereoscopic 3D patterns were successfully fabricated by the direct laser write (DLW) technique which demonstrated reversible swelling properties and reversible shape-memory effects induced via swelling and dehydration for the access to 4D printing.
Display omitted
•18 new synthetic derivatives selected from in silico molecular design were synthesized.•These dyes can initiate both free radical and cationic polymerizations.•The photopolymerization efficiency are excellent both for thin films and thick films.•3D patterns were successfully fabricated by the direct laser write (DLW) technique.•Swelling and dehydration induced shape-memory polymer network were prepared.
Improvement in panchromatic light-harvesting and photovoltaic performance is reported for dye-sensitized solar cells by adopting co-sensitization technique by mixing dyes. Betalain and Anthocyanin ...natural dyes are extracted from beetroot and cranberries. All dyes are characterized by UV–Vis and FTIR spectroscopy. Solar cells are fabricated and electrical characterizations are performed. Solar cell sensitized with mixed dyes demonstrated improved performance compared to cells of individual dyes, and yielded short circuit current density, open circuit voltage and fill factor of 0.36 mA/cm2, 0.42 V and 0.51 respectively. Their maximum efficiency is 5.37 and 1.16 times higher than that of individual beetroot and cranberry dye DSSCs respectively. Charge transfer processes are studied by impedance spectroscopy characterizations. The obtained results are in close agreement with commercially available N3 dye DSSC. The results yield that mixing dyes from different natural sources can be a very effective to further improve the performance of DSSCs.
Recent interests of scientists in the natural dyes for not only textile colouration but also clean production of functional fabric materials, has led to the development and application of ancient ...nature-based sources of colourants. Historical textiles are considered as important artefacts that present the culture and society from antient time to contemporary centuries, as well as the database to develop the functional materials. Study of organic colourants in ancient textiles is an effective approach to investigate the historical dyeing science and technology, likewise evolve the bio-colourants for modern applications. Plant-based colouring matters were widely utilized since the early textile civilization until the early 20th century. Currently, several anthraquinone colourants are discovered from vegetation, especially the morindone which was widely used in traditional fabric dyeing techniques of Southeast Asia, India and the Pacific Islands. In this context, the principal focus of this study is anthraquinone-based morindone dye, started from a brief overview of natural anthraquinone dyes in historical textiles, followed by the detailed discussion on biological sources, extraction of morindin, modification to red morindone pigment, as well as the summary of mordanting and dyeing method. For intensive investigation of the practical utilization of organic morindone in historical textiles, some recent works using analytical methods including high performance liquid chromatography (HPLC) and surface-enhanced Raman spectroscopy (SERS), are thoroughly discussed. Furthermore, the potential antimicrobial and ultraviolet protective performances of morindone dye are analysed with respect to effective application of morindone in functional textiles.
•Anthraquinone-based morindone dye extracted from Rubiaceae family.•Morindone in the interaction with metal mordant and textile fibres.•Intensive investigation of morindone in historical textiles by HPLC and SERS.•Antimicrobial and UV protective properties of morindone dyed textiles.•Future perspectives of historical natural colourants for functional textiles.
The purpose of this community service is to empower the Family Welfare Empowerment (PKK) group by developing the creativity of natural dye batik products in order that they can become the typical ...batik of Mojorejo Village, Madiun Regency. The method of implementing the service activity is through the stages: 1) observation, 2) counseling, 3) training, and 4) evaluation. The target of service activity is the PKK group. The data collection technique used a questionnaire and an observation rubric. Descriptive data analysis is based on achievement indicators. Based on the questionnaire analysis, it was found that the creativity of the trainees increased by 40%. The motivation of the trainees increased by 70%. The understanding of the training participants about the process of making natural dyed batik increased by 90%. The conclusion of the service activity is that training on making Jumputan batik using natural dyes can increase the creativity of batik production, which is typical of Mojorejo Village, Madiun Regency.
The dye-sensitized solar cells were fabricated using different natural dyes extracted from the Ixora flower, Pongame leaves, Neem leaves, sunflower, and Almond fruit. TiO2 nanoparticle has been ...prepared via the solvothermal method. The prepared samples were characterized by structural properties of X-Ray Diffraction, Field Emission-Scanning Electron Microscope, EDAX, and High Resolution-Transmission Electron Microscope, Optical properties of UV–Visible and Fourier Transform Infrared Spectroscopy studies, and Conductivity studies of EIS spectra. The average crystallite size and structure of prepared particles is determined by the XRD, and FTIR confirmed the functional groups present in the prepared samples. And also band gap values were calculated using UV–Visible spectroscopy. The resistance and conductivity of the samples were identified using the EIS spectra. The effect of natural dye extract from chlorophyll and anthocyanin pigment group was investigated for the performance of J-V characterization. The efficiency of almond extract of solar cells is found to be greater than that of the other four extracts sensitized solar cells.
•The tertagonal structure of ZnO nanoparticles was synthesized via the solvothermal method.•The FESEM of the ZnO nanoparticles exhibits spherical shaped particles.•The electrochemical impedance analysis shows a good bonding behaviour for the almond fruits.•From the J-V curve, the efficiency of almond based TiO2 device given the best efficiency better than the other natural photo-anode devices.
The energy economy is highly dependent on oil, coal and natural gas, which constitute 37%, 27% and 20% of energy usage, respectively. However, the reserves of fossil fuels (e.g., crude oil) are ...limited and could run out in approximately 40 years based on a daily consumption of 82.5 million barrels and the current reserves to production (R/P) ratio. Solar energy is the source of nearly all energy on Earth. Of all renewable power sources, solar energy is the most easily exploitable, inexhaustible, quiet, and adaptable to different applications. Photovoltaic cells (PVCs) are devices that directly convert sunlight into electricity without pollution, sound, or moving parts, which makes them long-lasting and dependable. PVCs use an elegant method to take advantage of sunlight. Solar cells offer one of the most promising and environmentally friendly methods for producing electricity. This paper reviews the emergence, principles, electron kinetics and components of PVCs with a focus on the molecular engineering of several metal complexes, organic dyes and natural dyes that are used as photosensitisers in dye-sensitised solar cells (DSSCs).
The performance of dye sensitized solar cells is mainly based on the dye as a sensitizer. Natural dyes have become a viable alternative to expensive and rare organic sensitizers because of its low ...cost, easy attainability, abundance in supply of raw materials and no environment threat. Various components of a plant such as the flower petals, leaves and bark have been tested as sensitizers. The nature of these pigments together with other parameters has resulted in varying performance. This review briefly discusses the emergence, operation and components of dye sensitized solar cells together with the work done on natural dye based dye sensitized solar cells over the years.
Natural molecular dye, anthocyanin, is described here as safe sensitizer for TiO
2 particles in photo-degradation of organic contaminants in water. The dye is a promising replacement for the more ...costly and hazardous heavy metal based systems, such as CdS particles and Ru-compounds. TiO
2/anthocyanin effectively catalyzed the photo-degradation of methyl orange contaminant under solar simulator radiation. The new TiO
2/anthocyanin catalyst showed comparable efficiency to earlier systems, while avoiding their hazardous nature. When supported onto activated carbon (AC) particles, the resulting AC/TiO
2/anthocyanin system showed enhanced efficiency and ease of recovery from the catalytic reaction mixture. The natural dye molecules showed the tendency to degrade under photo-degradation conditions, just like earlier hazardous sensitizers. However, complete mineralization of anthocyanin occurred leaving no traces of organic species in solution. Sensitizer degradation caused deactivation of the supported catalyst on recovery. Such a shortcoming was overcome by re-treatment of the recovered catalysts with fresh dye.
Effects of different reaction parameters on the catalyst efficiency were studied. A mechanism, similar to earlier CdS-sensitized catalyst systems, is proposed for the TiO
2/anthocyanin catalyst.
Display omitted
A selection of historical textile fragments from the Venetian art dealer Moisè Michelangelo Guggenheim collection, ranging from XV to XVIII century, has been investigated by means of non-invasive ...techniques in order to reveal the coloring materials. Imaging was preliminarily used to visually investigate the selected artwork fragments in order to investigate their structure and conservation conditions; Fiber Optics Reflectance Spectroscopy (FORS) allowed recognizing the main natural dyestuffs, such as indigotin and anthraquinones-based compounds, except the yellow ones, difficultly identifiable when using this non-invasive technique. Collected spectroscopic data have been also elaborated by using a clustering algorithm that permitted to group collected spectra on the basis of similar properties and evidencing their inflection point wavelength as the most influencing feature.
Display omitted
•The antique dealer M. M. Guggenheim assembled a wide textile collection.•A selection of fabric fragments ranging from XV to XVIII century was studied.•FORS analysis allowed identifying dyestuffs such as indigotin and anthraquinones.•Flavonoids were found in yellow areas but no further classification was possible.•Clustering analysis allowed grouping FORS spectra according to their spectral similarities.
PDF
