Natural Colorants: Historical, Processing and Sustainable Prospects

New Findings Regarding the Effects of Selected Blue Food Colorants (Genipin, Patent Blue V, and Brilliant Blue FCF) on the Hemostatic Properties of Blood Components In Vitro

Natural and synthetic colorants present in food can modulate hemostasis, which includes the coagulation process and blood platelet activation. Some colorants have cardioprotective activity as well. However, the effect of genipin (a natural blue colorant) and synthetic blue colorants (including patent blue V and brilliant blue FCF) on hemostasis is not clear. In this study, we aimed to investigate the effects of three blue colorants-genipin, patent blue V, and brilliant blue FCF-on selected parameters of hemostasis in vitro. The anti- or pro-coagulant potential was assessed in human plasma by measuring the following coagulation times: thrombin time (TT), prothrombin time (PT), and activated partial thromboplastin time (APTT). Moreover, we used the Total Thrombus formation Analysis System (T-TAS, PL-chip) to evaluate the anti-platelet potential of the colorants in whole blood. We also measured their effect on the adhesion of washed blood platelets to fibrinogen and collagen. Lastly, the cytotoxicity of the colorants against blood platelets was assessed based on the activity of extracellular lactate dehydrogenase (LDH). We observed that genipin (at all concentrations (1-200 µM)) did not have a significant effect on the coagulation times (PT, APTT, and TT). However, genipin at the highest concentration (200 µM) and patent blue V at the concentrations of 1 and 10 µM significantly prolonged the time of occlusion measured using the T-TAS, which demonstrated their anti-platelet activity. We also observed that genipin decreased the adhesion of platelets to fibrinogen and collagen. Only patent blue V and brilliant blue FCF significantly shortened the APTT (at the concentration of 10 µM) and TT (at concentrations of 1 and 10 µM), demonstrating pro-coagulant activity. These synthetic blue colorants also modulated the process of human blood platelet adhesion, stimulating the adhesion to fibrinogen and inhibiting the adhesion to collagen. The results demonstrate that genipin is not toxic. In addition, because of its ability to reduce blood platelet activation, genipin holds promise as a novel and valuable agent that improves the health of the cardiovascular system and reduces the risk of cardiovascular diseases. However, the mechanism of its anti-platelet activity remains unclear and requires further studies. Its in vivo activity and interaction with various anti-coagulant and anti-thrombotic drugs, including aspirin and its derivatives, should be examined as well.

Encapsulation of polyketide colorants in chitosan and maltodextrin microparticles

This study aimed to encapsulate Talaromyces amestolkiae colorants in maltodextrin and chitosan microparticles using the spraydrying technique and to evaluate the biopolymers' capacities to protect the fungal colorant against temperature (65 °C) and extreme pH (2.0 and 13.0). The compact microparticles exhibited smooth or indented surfaces with internal diameters ranging between 2.58-4.69 μm and ζ ~ -26 mV. The encapsulation efficiencies were 86 % and 56 % for chitosan and maltodextrin microparticles, respectively. The shifted endothermic peaks of the free colorants indicated their physical stabilization into microparticles. The encapsulated colorants retained most of their absorbance (compared to the 0 h) even after 25 days at 65 °C. Contrary, the free colorant presented almost no absorbance after 1 day under the same conditions. Colorants in chitosan and maltodextrin matrices also partially maintained their colorimetric and fluorometric properties at acidic pH. However, only maltodextrin improved the resistance of the red colorant to alkaline environments. For the first time, the potential of polysaccharide-based microparticles to preserve polyketide colorants was demonstrated using 3D fluorescence. Therefore, this study demonstrated an alternative in developing functional products with natural color additives.

Exploring colorant production by amazonian filamentous fungi: Stability and applications

The aim of this study was to investigate the production, stability and applicability of colorants produced by filamentous fungi isolated from soil samples from the Amazon. Initially, the isolates were evaluated in a screening for the production of colorants. The influences of cultivation and nutritional conditions on the production of colorants by fungal isolates were investigated. The colorants produced by selected fungal isolates were chemically characterized using the Liquid Chromatography-Mass Spectrometry technique. The antimicrobial and cytotoxic activities, stability evaluation and applicability of the colorants were investigated. As results, we observed that the isolates Penicillium sclerotiorum P3SO224, Clonostachys rosea P2SO329 and Penicillium gravinicasei P3SO332 stood out since they produced the most intense colorants. Compounds produced by Penicillium sclerotiorum P3SO224 and Clonostachys rosea P2SO329 were identified as sclerotiorin and penicillic acid. The colorant fraction (EtOAc) produced by these species has antimicrobial activity, stability at temperature and at different pHs, stability when exposure to light and UV, and when exposed to different concentrations of salts, as well as being nontoxic and having the ability to dye fabrics and be used as a pigment in creams and soap. Considering the results found in this study, it was concluded that fungi from the soil in the Amazon have the potential to produce colorants with applications in the textile and pharmaceutical industries.

Identification, extraction, and application of orange peel color extracts for silk fabric coloration

Under-utilized orange peel waste contains natural colorants that might be used for textile dyeing. Research into orange peel waste as natural colorants provides benefits for both the agricultural and fashion industry with a creative and sustainable solution. This research performed the extraction of colorants from the orange peel as plant dyes and investigated their potential dyeing capability of silk fabrics. With full factorial analysis, we determined the optimal extraction conditions by comparing 100 % ethanol, 70 % ethanol, and water, aiming to achieve the highest absorbance for the extracted solution. Conditions obtained with the best performance include an extraction temperature of 60 °C, an extraction time of 120 min, and a material-to-liquor ratio of 1:20 (wt/vol) for both 100 % and 0 % ethanol. To attain the highest K/S values on textiles with orthogonal experimental design, the optimal dyeing profiles of silk fabrics with water solution were found to be 100 °C, 60 min, pH 3, and Liquid Ratio of 1:15. Colorfastness results of crocking, washing, and sunlight are in favor of the usage of orange peel color extracts for textile application.

Parietin, the Vibrant Natural Dye in Xanthoria parietina

The use of natural dyes in several areas is regulated by current European and non-European legislation, due to various problems with synthetic dyes. The analysis revealed that the lichen studied: Xanthoria parietina has potential natural dye sources and provides bright colors for extraction solvents. Furthermore, dyed wool and toile fabric have good fastness properties in ammonia fermentation and boiling water, both with and without mordants. The sample dyes with Xanthoria parietina were characterized by several analytical techniques: high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization with tandem mass spectrometry (HPLC-ESI-Q-ToF). As compounds from Xanthoria parietina form a complex with mordants and tissues, it is impossible to identify the molecules responsible for coloring using chromatographic techniques. However, we have evaluated the dyeing power of their major molecule, parietin. To further confirm the coloring power of the isolated parietin molecule, we performed a dye test with pure parietin. Thus, CIALAB analyses have shown parietin is the molecule responsible for the coloring obtained by Xanthoria parietina. The utilization of parietin derived from lichens facilitates the development of sustainable dyes for textile coloring, presenting an environmentally friendly alternative to synthetic dyes while simultaneously enriching lichen biodiversity.

Microbial Pigments: Major Groups and Industrial Applications

Microbial pigments have many structures and functions with excellent characteristics, such as being biodegradable, non-toxic, and ecologically friendly, constituting an important source of pigments. Industrial production presents a bottleneck in production cost that restricts large-scale commercialization. However, microbial pigments are progressively gaining popularity because of their health advantages. The development of metabolic engineering and cost reduction of the bioprocess using industry by-products opened possibilities for cost and quality improvements in all production phases. We are thus addressing several points related to microbial pigments, including the major classes and structures found, the advantages of use, the biotechnological applications in different industrial sectors, their characteristics, and their impacts on the environment and society.

Decolorization of various dyes by microorganisms and green-synthesized nanoparticles: current and future perspective

Various types of colored pigments have been recovered naturally from biological sources including shells, flowers, insects, and so on in the past. At present, such natural colored substances (dyes) are replaced by manmade dyes. On the other hand, due to their continuous usage in various purpose, these artificial dyes or colored substances persist in the environmental surroundings. For example, industrial wastewater contains diverse pollutant substances including dyes. Several of these (artificial dyes) were found to be toxic to living organisms. In recent times, microbial-based removal of dye(s) has gained more attention. These methods were relatively inexpensive for eliminating such contaminants in the environmental system. Hence, various researchers were isolated microbes from environmental samples having the capability of decolorizing synthetic dyes from industrial wastewater. Furthermore, the microorganisms which are genetically engineered found higher degradative/decolorize capacity to target compounds in the natural environs. Very few reviews are available on specific dye treatment either by chemical treatments or by bacteria and/or fungal treatments. Here, we have enlightened literature reports on the removal of different dyes in microbes like bacteria (including anaerobic and aerobic), fungi, GEM, and microbial enzymes and also green-synthesized nanoparticles. This up-to-date literature survey will help environmental managements to co-up such contaminates in nature and will help in the decolorization of dyes.

Natural colour extraction from horticultural crops, advancements, and applications-a review

The scope for natural colours is increasing because of the awareness of allergic, toxic, and hazardous reactions associated with synthetic dyes. Natural colours are extracted from sources that are naturally available, such as flora, fauna, and minerals. Nature sourced us multiple possibilities of colours with varied shades and hues that are subtle and harmonious when combined. Reasons like the instability of natural colours during industrial processing, seasonal availability of raw materials, fading of colour over time, cost of the benefit, and struggles in attaining sustainability have reduced commercialisation success as synthetic colours. Some plants that yield natural colours are also included in crop rotation practice. Natural dye extraction is a source of employment for the countrified subdivisions of poor developing countries. Indigenous technologies on natural colour extraction are available and have been practiced over the years; due to a lack of documentation and information on colour-yielding plants or products from horticultural crops, and their extraction methods, the use of natural colours is diminishing day by day. Even in recent years, emerging techniques have been adopted in research and development, and the information has not been brought together for the use of industries and allied sectors. Several modern approaches, such as Ultrasonication, microwave, enzymatic, supercritical, pressurised liquid extraction, etc., have proven to give better results in extracting natural colours. Thereby, having instantaneous information will help to go green, be eco-friendly, and effectively utilise all the resources without compromising industrial benefits. Reviewing the availability of natural colours from horticultural crops, classifications, recent trends in their extraction process, and applications in various fields will help achieve the above.

Plant Extracts as Skin Care and Therapeutic Agents

Natural ingredients have been used for centuries for skin treatment and care. Interest in the health effects of plants has recently increased due to their safety and applicability in the formulation of pharmaceuticals and cosmetics. Long-known plant materials as well as newly discovered ones are increasingly being used in natural products of plant origin. This review highlights the beneficial effects of plants and plant constituents on the skin, including moisturizing (e.g., Cannabis sativa, Hydrangea serrata, Pradosia mutisii and Carthamus tinctorius), anti-aging (e.g., Aegopodium podagraria, Euphorbia characias, Premna odorata and Warburgia salutaris), antimicrobial (e.g., Betula pendula and Epilobium angustifolium), antioxidant (e.g., Kadsura coccinea, Rosmarinus officinalis, Rubus idaeus and Spatholobus suberectus), anti-inflammatory (e.g., Antidesma thwaitesianum, Helianthus annuus, Oenanthe javanica, Penthorum chinense, Ranunculus bulumei and Zanthoxylum bungeanum), regenerative (e.g., Aloe vera, Angelica polymorpha, Digitaria ciliaris, Glycyrrihza glabra and Marantodes pumilum), wound healing (e.g., Agrimonia eupatoria, Astragalus floccosus, Bursera morelensis, Jatropha neopauciflora and Sapindus mukorossi), photoprotective (e.g., Astragalus gombiformis, Calea fruticose, Euphorbia characias and Posoqueria latifolia) and anti-tyrosinase activity (e.g., Aerva lanata, Bruguiera gymnorhiza, Dodonaea viscosa, Lonicera japonica and Schisandra chinensis), as well as their role as excipients in cosmetics (coloring (e.g., Beta vulgaris, Centaurea cyanus, Hibiscus sabdariffa and Rubia tinctiorum), protective and aromatic agents (e.g., Hyssopus officinalis, Melaleuca alternifolia, Pelargonium graveolens and Verbena officinalis)).

Genipa americana L.: A New Phytochemical for White Hair Coloring

This work describes a new hair dyeing methodology using a chemical reaction between geniposide, an iridoid glycoside extracted from the fruit of Genipa americana (geniposide extract, GE) and the amine group of hair keratin. The influence of reaction conditions (pH, temperature, and extract concentration) on the staining of hair fibers, color development, fiber morphology, and mechanical hair properties of black and white human hair samples, was evaluated before and after GE dyeing treatment. Eye contact safety of GE was also studied using HET-CAM. The treatment of white hair fibers using GE at 20 mg mL-1 , temperature of 80 °C and pH 5.5 presented the greatest color change (ΔE=54.0). The higher pH influence was observed at pH 10.0 on white hair tresses (ΔE=6.8), using an GE concentration of 20 mg mL-1 and room temperature (25 °C). Treated samples showed marked changes on mechanical and morphological properties. The HET-CAM did not show any change, thus demonstrating that using GE is safe. In conclusion, the temperature and concentration of the extract were the variables that mostly influenced the color and hair damage. A new approach for hair dyeing was established where iridoids may potentially be useful as a natural hair dyeing.

Sustainable production of bacterioruberin carotenoid and its derivatives from Arthrobacter agilis NP20 on whey-based medium: optimization and product characterization

Bacterioruberin and its rare glycosylated derivatives are produced by Arthrobacter agilis as an adaptation strategy to low temperature conditions. The high antioxidant properties of bacterioruberin held great promise for different future applications like the pharmaceutical and food industries. Microbial production of bacterioruberin via a cost-effective medium will help increase its commercial availability and industrial use. The presented study aims to optimize the production of the rare C50 carotenoid bacterioruberin and its derivatives from the psychotrophic bacteria Arthrobacter agilis NP20 strain on a whey-based medium as a cost effective and readily available nutritious substrate. The aim of the study is extended to assess the efficiency of whey treatment in terms of estimating total nitrogen content in treated and untreated whey samples. The significance of medium ingredients on process outcome was first tested individually; then the most promising factors were further optimized using Box Behnken design (BBD). The produced carotenoids were characterized using UV-visible spectroscopy, FTIR spectroscopy, HPLC-DAD chromatography and HPLC-APCI-MS spectrometry. The maximum pigment yield (5.13 mg/L) was achieved after a 72-h incubation period on a core medium composed of 96% sweet whey supplemented with 0.46% MgSO4 & 0.5% yeast extract and inoculated with 6% (v/v) of a 24 h pre-culture (109 CFU/mL). The cost of the formulated medium was 1.58 $/L compared with 30.1 $/L of Bacto marine broth medium. The extracted carotenoids were identified as bacterioruberin, bis-anhydrobacteriouberin, mono anhydrobacterioruberin, and glycosylated bacterioruberin. The presented work illustrates the possibility of producing bacterioruberin carotenoid from Arthrobacter agilis through a cost-effective and eco-friendly approach using cheese whey-based medium.

Agro-waste to sustainable energy: A green strategy of converting agricultural waste to nano-enabled energy applications

The rising demands of the growing population have raised two significant global challenges viz. energy crisis and solid-waste management, ultimately leading to environmental deterioration. Agricultural waste (agro-waste) contributes to a large amount of globally produced solid waste, contaminating the environment, and raising human-health issues on improper management. It is essential for a circular economy to meet sustainable development goals and to design strategies to convert agro-waste into energy using nanotechnology-based processing strategies, by addressing the two significant challenges. This review illustrates the nano-strategic aspects of state-of-the-art agro-waste applications for energy harvesting and storage. It details the fundamentals related to converting agro-waste into energy resources in the form of green nanomaterials, biofuels, biogas, thermal energy, solar energy, triboelectricity, green hydrogen, and energy storage modules in supercapacitors and batteries. Besides, it highlights the challenges associated with agro-waste-to-green energy modules with their possible alternate solutions and advanced prospects. This comprehensive review will serve as a fundamental structure to guide future research on smart agro-waste management and nanotechnological innovations dedicated to its utilization for green energy applications without harming the environment. The nanomaterials assisted generation and storage of energy from agro-waste is touted to be the near-future of smart solid-waste management strategy for green and circular economy.

Progress and Prospective of the Industrial Development and Applications of Eco-Friendly Colorants: An Insight into Environmental Impact and Sustainability Issues

Color is the prime feature directly associated with the consumer's attraction and choice of their food. The flavor, safety, and nutritional value of any food product are directly associated with the food color. Natural and synthetic colorants (dyes and pigments) have diversified applications in various sectors such as food, feed, pharmaceutical, textiles, cosmetics, and others. Concerning the food industry, different types of natural and synthetic colorants are available in the market. Synthetic food colorants have gained popularity as they are highly stable and cheaply available. Consumers worldwide prefer delightful foodstuffs but are more concerned about the safety of the food. After its disposal, the colloidal particles present in the synthetic colorants do not allow sunlight to penetrate aquatic bodies. This causes a foul smell and turbidity formation and gives a bad appearance. Furthermore, different studies carried out previously have presented the toxicological, carcinogenic effects, hypersensitivity reactions, and behavioral changes linked to the usage of synthetic colorants. Natural food colorings, however, have nutraceutical qualities that are valuable to human health such as curcumin extracted from turmeric and beta-carotene extracted from carrots. In addition, natural colorants have beneficial properties such as excellent antioxidant properties, antimutagenic, anti-inflammatory, antineoplastic, and antiarthritic effects. This review summarizes the sources of natural and synthetic colorants, their production rate, demand, extraction, and characterization of food colorants, their industrial applications, environmental impact, challenges in the sustainable utilization of natural colorants, and their prospects.

A review of plant-based natural dyes in leather application with a special focus on color fastness characteristics

Dyes/colorants are normally used to improve the aesthetic of consumer products, and leather is one of them. The leather industry plays a significant role in the global economy. However, the leather-making process causes severe environmental pollution. Synthetic dyes are one of the major classes of leather chemicals that are responsible for the enhanced pollution load created by the industry. Over the years, excessive use of synthetic dyes in consumer products created severe environmental pollution and health hazard. Many of these synthetic dyes are carcinogenic, allergic, cause serious health problems for human beings, and have been restricted by regulatory authorities for use in consumer goods. Since ancient days, natural dyes and colorants have been used to make lives colorful. Amid the green movements and environment-friendly products/processes, natural dyes are back to mainstream fashion. Moreover, natural colorants have become a trend due to their eco-friendly nature. The demand for non-toxic and eco-friendly dyes and pigments is increasing. However, the question remains "is natural dyeing sustainable" or "how to make it sustainable." Here, we review the literature reports on natural dye's application in leather in the last two decades. This review article provides a detailed overview and current knowledge base on the various plant-based natural dyes used in leather dyeing, their fastness properties, and the need of the hour in terms of product and process development to make natural dying sustainable. The color fastness characteristics of the dyed leather to light, rub, and perspiration have been critically discussed.

Biopigments of Microbial Origin and Their Application in the Cosmetic Industry

Along with serving as a source of color, many microbial pigments have gained attention as interesting bioactive molecules with potential health advantages. These pigments have several applications in the food, agrochemical, medicine, and cosmetic industries. They have attracted the attention of these industries due to their high production value, low cost, stability, and biodegradability. Recently, many consumers worldwide have noted the impact of synthetic dyes; thus, natural pigments are more in demand than synthetic colors. On the other hand, the cosmetic industry has been moving toward greener manufacturing, from the formulation to the packaging material. Microbial pigments have several applications in the field of cosmetics due to their photoprotection, antioxidant, and antiaging properties, including inhibiting melanogenesis and acting as natural colorants for cosmetics, as some microorganisms are rich in pigments. More investigations are required to estimate the safety and efficacy of employing microbial pigments in cosmetic products. Furthermore, it is necessary to obtain information about DNA sequencing, metabolic pathways, and genetic engineering. In addition, unique habitats should be explored for novel pigments and new producing strains. Thus, new microbial pigments could be of consideration to the cosmetic industry, as they are ideal for future cosmetics with positive health effects.

Sustainable and Bio-Based Food Packaging: A Review on Past and Current Design Innovations

Food loss and waste occur for many reasons, from crop processing to household leftovers. Even though some waste generation is unavoidable, a considerable amount is due to supply chain inefficiencies and damage during transport and handling. Packaging design and materials innovations represent real opportunities to reduce food waste within the supply chain. Besides, changes in people's lifestyles have increased the demand for high-quality, fresh, minimally processed, and ready-to-eat food products with extended shelf-life, that need to meet strict and constantly renewed food safety regulations. In this regard, accurate monitoring of food quality and spoilage is necessary to diminish both health hazards and food waste. Thus, this work provides an overview of the most recent advances in the investigation and development of food packaging materials and design with the aim to improve food chain sustainability. Enhanced barrier and surface properties as well as active materials for food conservation are reviewed. Likewise, the function, importance, current availability, and future trends of intelligent and smart packaging systems are presented, especially considering biobased sensor development by 3D printing technology. In addition, driving factors affecting fully biobased packaging design and materials development and production are discussed, considering byproducts and waste minimization and revalorization, recyclability, biodegradability, and other possible ends-of-life and their impact on product/package system sustainability.

Characterization of a blue-green pigment extracted from Pseudomonas aeruginosa and its application in textile and paper dyeing

Microorganisms are a promising source of colorants with large economic potential. Owing to better bio-degradability and higher eco-compatibility, microbial pigments propose promising avenues and can thus be a smart substitute for artificial pigments. The present work focused on the screening, isolation, and extraction of a blue-green pigment produced by soil microorganisms. The pigment-producing microorganism was identified as Pseudomonas aeruginosa on the basis of standard biochemical tests and by 16S rRNA sequencing. The purified blue pigment was characterized by high-performance liquid chromatography and gas chromatography-mass spectrometry. The antimicrobial activity of the microbial biocolor (3 × 10⁸ CFU/ml) was studied, and the zone of inhibition was found to be 10 mm, 13 mm, 9 mm, and 7 mm for E. coli, S. aureus, B. subtilis, and S. typhi, respectively. The evaluation of the biocolor as a dye was executed on different types of textiles and paper. The dyed fabrics were checked for washing, rubbing, and light and temperature fastness. Standard fabric properties of the fabrics dyed with the extracted microbial pigment were also assessed. The dyed fabrics were finally subjected to a patch test to check for any kind of allergic or hypersensitivity on human skin. The extracted pigment from Pseudomonas aeruginosa exhibited remarkable dyeing properties, indicating the scope for utilization of the pigment as a colorant on different types of textile and paper materials. The present study highlights the application of a bacterial pigment as a dyeing agent, which may raise its market value and probably replace toxic synthetic dyes due to its nontoxic nature, compatibility with various textiles, and cost-effectiveness.

Dyeing of polyamide 6 fabric with new bio-colorant and bio-mordants

The present study investigates the natural dyeing of nylon fabric using the dragon's blood resin extract. Response surface methodology was used to optimize the process variables including pH (3-9), temperature (50-100 °C), concentration (10-50%owf), and time (30-90 min). From a visual point of view, diverse eco-friendly shades with a rather diverse color gamut of varied hue and tone were generated by applying a wide range of natural and eco-label mordants. The impact of 4 bio-mordants (including peppermint, mugworts (Artemisia), Dorema ammoniacum (DA) gum, and pomegranate rind), as well as 4 mineral mordants (alum, copper (II) sulfate, potassium dichromate, and iron (II) sulfate) on the color and fastness properties of the dyed nylon samples, was assessed. The concentration of the used mordants was 5%owf, and the dyeing experiments were conducted by applying the pre-mordanting technique. Measurement of the color strength (K/S) of the dyed fabric was done using a reflectance spectrophotometer. The dyed nylon fastness qualities and the colorimetric characteristics were then evaluated by applying the related standards. The results showed that the optimum conditions for obtaining the highest color strength were dye concentration = 50%owf, pH = 6, temperature = 100 °C, and dyeing tome = 60 min. The proposed ISO standards in relation to colorfastness displayed acceptable ratings for the color strength of dragon's blood resin dyed fabric while its treatment was done by applying bio-mordants in comparison to its metallic counterparts. Therefore, dragon's blood resin could be regarded as a promising eco-friendly natural colorant source for the purpose of sustainable nylon dyeing.

Advances in Genetic Engineering in Improving Photosynthesis and Microalgal Productivity

Even though sunlight energy far outweighs the energy required by human activities, its utilization is a key goal in the field of renewable energies. Microalgae have emerged as a promising new and sustainable feedstock for meeting rising food and feed demand. Because traditional methods of microalgal improvement are likely to have reached their limits, genetic engineering is expected to allow for further increases in the photosynthesis and productivity of microalgae. Understanding the mechanisms that control photosynthesis will enable researchers to identify targets for genetic engineering and, in the end, increase biomass yield, offsetting the costs of cultivation systems and downstream biomass processing. This review describes the molecular events that happen during photosynthesis and microalgal productivity through genetic engineering and discusses future strategies and the limitations of genetic engineering in microalgal productivity. We highlight the major achievements in manipulating the fundamental mechanisms of microalgal photosynthesis and biomass production, as well as promising approaches for making significant contributions to upcoming microalgal-based biotechnology.

An eco-friendly method of extracting alizarin from Rubia tinctorum roots under supercritical carbon dioxide and its application to wool dyeing

Because of its low critical temperature and pressure levels, supercritical carbon dioxide (scCO₂) is the most widely used supercritical fluid in the supercritical fluid extraction (SFE) technique. Alizarin was extracted from madder roots (Rubia tinctorum) using scCO₂ under different conditions of co-solvent ratio (0-50%), temperature (45-95 °C), pressure (150-250 bar), extraction time (15-120 min), and flow rate (5-9 mL/min). Based on alizarin recovery and minimization of environmental risk, the optimum conditions were determined. SFE was optimum at 90% CO₂:10% methanol (Me), 65 °C, 250 bar, 45 min, and 9 mL/min. The alizarin recovery, and its content in R. tinctorum extract (RE) under the optimum conditions were 1.34 g/kg roots, and 6.42%, respectively. Using conventional dyeing methods, wool fabrics were dyed with RE at different concentrations (2-6%). Various types of mordants were also used in the dyeing process, including chemical and bio-mordants. Color and fastness properties of dyed wool fabrics were evaluated based on RE concentration and mordant type. A higher RE concentration and the use of mordants, specifically Punica granatum (P. granatum) peels, increased the color characteristics. RE and dyed fabrics exhibited good antibacterial activity against the tested bacterial strains, especially Pseudomonas aeruginosa and Escherichia coli.

Ion-in-Conjugation: A Promising Concept for Multifunctional Organic Semiconductors

Most organic semiconductors (OSCs) consist of conjugated skeletons with flexible peripheral chains. Their weak intermolecular interactions from dispersion and induction forces result in environmental susceptibilities and are unsuitable for many multifunctional applications where direct exposure to external environments is unavoidable, such as gas absorption, chemical sensing, and catalysis. To exploit the advantages of inorganic semiconductors in OSCs, ion-in-conjugation (IIC) materials are proposed. An IIC material refers to any conjugated material (molecules, polymers, and crystals) in Kekule's structural formula containing stoichiometric ionic states in its conjugated backbone in the electronic ground state. In this review, the definitions, structures, synthesis, properties, and applications of IIC materials are described briefly. Four types of IIC material, including zwitterionic conjugated molecules/polymers, conjugated ionic dyes, π-d conjugated molecules and polymers, and coordinatively doped polymers, are reported. Their applications in gas sensing, humidity sensing, resistive memory devices, and thermal/photo-/electro-catalysis are demonstrated. The challenges and opportunities for future research are also discussed. It is expected that this work will inspire the design of new organic electronic information materials.

Optimization and multiple in vitro activity potentials of carotenoids from marine Kocuria sp. RAM1

Marine pigmented bacteria are a promising natural source of carotenoids. Kocuria sp. RAM1 was isolated from the Red Sea Bohadschia graeffei collected from Marsa Alam, Egypt, and used for carotenoids production. The extracted carotenoids were purified by thin-layer chromatography (TLC). The characteristic UV absorbance of the three purified fractions gave us an inkling of what the purified pigments were. The chemical structures were confirmed by nuclear magnetic resonance spectroscopy (NMR) and LC-ESI-QTOF-MS/MS. The three different red pigments were identified as two C₅₀-carotenoids, namely bisanhydrobacterioruberin and trisanhydrobacterioruberin, in addition to 3,4,3',4'-Tetrahydrospirilloxanthin (C₄₂-carotenoids). Kocuria sp. RAM1 carotenoids were investigated for multiple activities, including antimicrobial, anti-inflammatory, antioxidant, anti-HSV-1, anticancer, antidiabetic and wound healing. These new observations suggest that Kocuria sp. RAM1 carotenoids can be used as a distinctive natural pigment with potent properties.

Study of Dyeing Process of Hemp/Cotton Fabrics by Using Natural Dyes Obtained from Rubia tinctorum L. and Calendula officialis

The objective of this work was to assess the possibility of dyeing a substrate composed of non-textile industrial hemp using natural dyes from common madder (Rubia Tinctorum L.) and calendula (Calendula Officialis) and tannin and alum as mordants. The substrate used for the dyeing had a 25/75 hemp/cotton composition. The hemp raw material is an agricultural by-product that was subjected to mechanical and chemical treatments in order to cottonize the fibers, blend them with cotton, and thus obtain first 40-tex open-end yarns and then a knitted fabric. The latter was subjected to different dyeing conditions by varying the dye, mordant, and method for its application, type of water, and rinsing after dyeing. Measurements of the difference (ΔE) and intensity (K/S) of color and fastness to washing and rubbing were carried out. The results showed that dyeing of a non-textile residual hemp substrate is possible, and that calendula is a good option for dyeing it with tap water, tannin-alum set in a meta-mordanting process, and rinsing after 24 h. In this way, a contribution has been made to the circular economy of the textile industry through the use of more sustainable sources and products.

Production of Natural Pigments by Penicillium brevicompactum Using Agro-Industrial Byproducts

The demand for natural pigments for industrial applications has significantly increased. Penicillium brevicompactum was recently reported as a promising pigments producer using submerged fermentation and a synthetic culture medium containing lactose. In this work, pigment production by P. brevicompactum was studied under different fermentation conditions, namely, submerged fermentation with free (SmF) and immobilized mycelium (SmFi), and solid-state fermentation (SSF). The potential of culture media composed of agro-industrial byproducts (cheese-whey (CW) and corn steep liquor (CSL)) was investigated for the first time as low-cost alternatives to pigment production by P. brevicompactum. The fungus showed great adaptability to the different culture media and types of fermentation, being able to synthesize pigments under all the tested conditions. A culture medium composed of 34.6 g/L of CW and 8 g/L of CSL proved to be the most suitable alternative to the synthetic medium, especially under SmF and SmFi. Our data also show that different mixtures of pigments (yellow, orange, and red) can be produced depending on the medium composition and the type of fermentation. Additionally, the immobilization and reuse of biomass to produce pigments by P. brevicompactum were demonstrated for the first time, suggesting the possibility of operating under repeated batch mode at an industrial scale.

Preparation of Biocomposites with Natural Reinforcements: The Effect of Native Starch and Sugarcane Bagasse Fibers

Biocomposites were prepared from poly(lactic acid) and two natural reinforcements, a native starch and sugarcane bagasse fibers. The strength of interfacial adhesion was estimated by model calculations, and local deformation processes were followed by acoustic emission testing. The results showed that the two additives influence properties differently. The strength of interfacial adhesion and thus the extent of reinforcement are similar because of similarities in chemical structure, the large number of OH groups in both reinforcements. Relatively strong interfacial adhesion develops between the components, which renders coupling inefficient. Dissimilar particle characteristics influence local deformation processes considerably. The smaller particle size of starch results in larger debonding stress and thus larger composite strength. The fracture of the bagasse fibers leads to larger energy consumption and to increased impact resistance. Although the environmental benefit of the prepared biocomposites is similar, the overall performance of the bagasse fiber reinforced PLA composites is better than that offered by the PLA/starch composites.

Design and Preparation of a Biobased Colorimetric pH Indicator from Cellulose and Pigments of Bacterial Origin, for Potential Application as Smart Food Packaging

Nowadays, worldwide challenges such as global warming, pollution, unsustainable consumption patterns, and scarcity of natural resources are key drivers toward future-oriented bioeconomy strategies, which rely on renewable biobased resources, such as bacterial pigments and bacterial cellulose (BC), for materials production. Therefore, the purpose of this study was to functionalize bacterial cellulose with violacein, flexirubin-type pigment, and prodigiosin and test their suitability as pH indicators, due to the pigments’ sensitivity to pH alterations. The screening of the most suitable conditions to obtain the BC-pigment indicators was achieved using a full factorial design, for a more sustainable functionalization process. Then, the pH response of functionalized BC to buffer solutions was assessed, with color changes at acidic pH (BC-violacein indicator) and at alkaline pH (BC-violacein, BC-prodigiosin, and BC-flexirubin-type pigment indicators). Moreover, the indicators also revealed sensitivity to acid and base vapors. Furthermore, leaching evaluation of the produced indicators showed higher suitability for aqueous foods. Additionally, color stability of the functionalized BC indicators was carried out, after light exposure and storage at 4 °C, to evaluate the indicators’ capacity to maintain color/sensitivity. Thus, BC membranes functionalized with bacterial pigments have the potential to be further developed and used as pH indicators.

Ascomycota as a source of natural colorants

In the last few decades, there has been a great demand for natural colorants. Synthetic colorants are known to be easy to produce, are less expensive, and remain stable when subjected to chemical and physical factors. In addition, only small amounts are required to color any material, and unwanted flavors and aromas are not incorporated into the product. Natural colorants present in food, in addition to providing color, also have biological properties and effects that aid in the prevention and cure of many diseases. The main classes of colorants produced by phylum Ascomycota include polyketides and carotenoids. A promising producer of colorants should be able to assimilate a variety of sources of carbon and nitrogen and also exhibit relative stability. The strain should not be pathogenic, and its product should not be toxic. Production processes should also provide the expected color with a good yield through simple extraction methods. Research that seeks new sources of these compounds should continue to seek products of biotechnological origin in order to be competitive with products of synthetic and plant origin. In this review, we will focus on the recent studies on the main producing species, classes, and metabolic pathways of colorants produced by this phylum, historical background, impact of synthetic colorants on human health and the environment, social demand for natural colorants and also an in-depth approach to bioprocesses (influences on production, optimization of bioprocess, extraction, and identification), and limitations and perspectives for the use of fungal-based dyes.

Method Validation and Characterization of Red Pigment in Beta vulgaris Peels and Pomaces by HPLC-UV and UHPLC-MS/MS

Color pigments from plant, animal, or mineral sources can be identified, separated, and quantified for various purposes. It is expected that pigments from Beta vulgaris L. peels and pomaces could be used to develop natural dyes that can find applications in areas such as food or textile dyeing industries. This work aimed at identifying and quantifying the pigment in the B. vulgaris L. peels and pomaces extracts as well as validating the method by high-performance liquid chromatography combined with ultraviolet spectroscopy (HPLC-UV) and ultra-high-performance liquid chromatography coupled with triple quadrupole (TSQ) mass spectrometry (UHPLC-MS/MS). Column chromatography was used to isolate compounds after methanolic solvent extraction. Identification and quantification of the pigments in the extract were achieved using reverse-phase HPLC with a UV detector (538 nm). The UHPLC-MS/MS was used for further confirmation of colored compounds in the extract. Method validation included the use of betanin standard (betanidin 5-β-D-glucopyranoside), determination of repeatability (precision), calibration curve linearity, and sensitivity (LOD and LOQ) tests. Betanin was detected in the sample at retention times of 7.699 and 7.71 minutes, respectively, which closely matched the tR (7.60 min) of the standard, according to HPLC-UV and LC-MS/MS data. The average betanin concentration was 3.81 0.31 mg/g of dry weight, according to the HPLC-UV analysis. The LC-MS/MS data revealed the existence of several compounds, including betanin (4.31 ± 2.15 mg/g), isobetanin (1.85 ± 2.20 mg/g), 2, 17-bidecarboxy-neobetanin (0.71 ± 0.02 mg/g), betanidin (0.71 ± 0.03 mg/g), 2-O-glucosyl-betanin (0.40 ± 0.10 mg/g), and isobetanidin (0.36 ± 1.26 mg/g), among other compounds whose yields were too low. In conclusion, the peels and pomaces of B. vulgaris L. can be a useful source for the extraction of a red dye for use in coloring, such as the dyeing of textile substrates.

FT-IR Analysis of Beta vulgaris Peels and Pomace Dye Extracts and Surface Analysis of Optimally Dyed-Mordanted Cellulosic Fabrics

FT-IR spectroscopy is a nondestructive technique that can be utilized for the qualitative characterization of natural dyes and dyed substrates through structure elucidation. This work aimed at the characterization of natural dye extract from Beta vulgaris peels and pomaces and surface analysis of optimally dyed-mordanted cotton (cellulosic) fabric using Fourier Transform Infrared (FT-IR) spectroscopy, as well as colour fastness tests (light, washing, rubbing, and perspiration). Response surface methodology (RSM) was employed in the optimization of dyeing temperature (T), time (t), and pH, as well as applying the relative percent change in colour strength (ΔE) of dyed fabrics as the response. The natural mordants (tannic acid-alum) were compared with synthetic mordants (K2Cr2O7, FeSO4, and CuSO4) using the three mordanting methods. The optimized dyeing parameters were T (55°C), t (75 minutes), and pH (6.5), as a result of comparatively high relative % ΔE (11%). The FT-IR analysis of the extract revealed different characteristic absorption peak values for various functional groups: 3282.82 cm−1 (–OH stretch), 2932.96 cm−1 (C–H stretch), and 1588.91 cm−1 (C=N stretch), among others. The C=N bond stretch biomarks the presence of nitrogen-containing compounds such as the reddish betanin pigments. $p>0.05$ of the dyeing parameters implied that they are not significant but affect dyeing probably alongside other factors such as mordanting. The spectral analysis of bleached and optimally dyed (nonmordanted and mordanted) fabrics revealed varied peaks indicating different functional groups suggesting the presence of cellulose and the binding of mordants with chromophores in the dye extract which yield different shades. Postmordanting showed mean ratings of 4-5 (excellent) among all fastness tests, displayed by tannic acid-alum, FeSO4, and CuSO4. Generally, mordanting resulted in enhanced dye stability and improved colour fastness. To identify specific chromophores in dye extracts and their molecular configurations due to mordants, advanced FT-IR hyphenated systems can be employed.

Use of bacterial isolates in the treatment of textile dye wastewater: A review

The textile industry uses large amounts of dyes like reactive, azo, anthraquinone, and triphenylmethane to colour textiles. Dyes that are not used up during the colouration process usually end up in water bodies as waste leading to the pollution of the water bodies. This makes the industry to be one of the major contributors to water pollution in the world. Bacterial agents isolated from various sources like dye contaminated soil and textile wastewater have shown to have the ability to effectively decolourise and degrade these dye pollutants leading to improved water quality. This review discusses bacterial isolates that have been used successfully to degrade and decolourise textile dyes, their mode of dye removal as well as the factors that affect their dye degradation ability. It further looks at the latest wastewater treatment technologies that incorporate bacterial microorganisms to treat dye wastewater.

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Bacterial isolates offer environmentally friendly solution to dye degradation.

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Pure and mixed bacterial cultures can remove textile dyes in optimised conditions.

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Dyes are removed through biosorption or biodegradation mechanisms.

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Latest technologies provide more effective dye removal options.

Recent and Emerging Trends in Remediation of Methylene Blue Dye from Wastewater by Using Zinc Oxide Nanoparticles

Due to the increased demand for clothes by the growing population, the dye-based sectors have seen fast growth in the recent decade. Among all the dyes, methylene blue dye is the most commonly used in textiles, resulting in dye effluent contamination. It is carcinogenic, which raises the stakes for the environment. The numerous sources of methylene blue dye and their effective treatment procedures are addressed in the current review. Even among nanoparticles, photocatalytic materials, such as TiO2, ZnO, and Fe3O4, have shown greater potential for photocatalytic methylene blue degradation. Such nano-sized metal oxides are the most ideal materials for the removal of water pollutants, as these materials are related to the qualities of flexibility, simplicity, efficiency, versatility, and high surface reactivity. The use of nanoparticles generated from waste materials to remediate methylene blue is highlighted in the present review.

Leather Dyeing by Plant-Derived Colorants in the Presence of Natural Additives

This research aimed to dye leather fabric samples with the application of plant-derived colorants and natural additives. Two grades of chitosan were used as additives, in addition to caffeine, nettle extract, and shellac solution. The ability of colorants to dye leather fabric and the impact of additives on leather fabric properties such as structure, color intensity, color stability under exposure to UVC irradiation, and mechanical properties were examined. For this purpose, dyed samples were tested by a colorimeter, ATR-FTIR spectrophotometer, mechanical testing machine, and X-ray diffractometer. The results indicated that the applied colorants of plant origin have the potential to dye leather fabrics without affecting their structure and without a negative impact on the environment. Applied natural additives can, therefore, beneficially influence the effects of the dyeing process, such as color intensity, colorfastness after exposure to UV irradiation, or tensile strength of the material.

Biosynthesis and biotechnological interventions for commercial production of microalgal pigments: A review

Microalgae are photosynthetic eukaryotes that serve as microbial cell factories for the production of useful biochemicals, including pigments. These pigments are eco-friendly alternatives to synthetic dyes and reduce environmental and health risks. They also exhibit excellent anti-oxidative properties, making them a useful commodity in the nutrition and pharmaceutical industries. Light-harvesting pigments such as chlorophylls and phycobilins, and photoprotective carotenoids are some of the most common microalgal pigments. The increasing demand for these pigments in industrial applications has prompted a need to improve their metabolic yield in microalgal cells. So far, expensive cultivation methods and sensitivity to microbial contamination remain the main obstacles to the large-scale production of these pigments. This review highlights current issues and future prospects related to the production of microalgal pigments. The review also emphasizes the use of engineering approaches such as genetic engineering, and optimization of media components and physical parameters to increase their commercial-scale production.

Molecular characterization and ecotoxicological evaluation of the natural dye madder and its chlorinated products

There has been increased interest in the use of natural dyes for textile coloration as alternatives to synthetic dyes, due to the general belief that natural dyes are more environmentally friendly. However, natural dyes have poor affinity for textiles, which can lead to high dye levels in the resultant wastewater. While chlorine treatment has proven to be effective for dye wastewater disinfection and decolorization, this process can also lead to the formation of more toxic degradation products for certain synthetic dyes. On the other hand, little information is available regarding the ecotoxicity of natural dyes and their chlorination products. To advance knowledge in this area, madder was selected due to its historical importance and wide application in the textile industry. Specifically, we sought to characterize the chlorine-induced degradation products of an aqueous madder solution and to assess their ecotoxicity. The main component of the present madder sample was Alizarin (89.8%). Chlorination led to complete decolorization, and 2-hydroxynaphthalene-1,4-dione and phthalic anhydride were identified as key degradation products. Chlorination of madder decreased toxicity to Daphnia similis (microcrustacean) 10-fold and removed the toxicity to Raphidocellis subcapitata (algae), when compared to the parent dye.

Production of coffee-dyed bacterial cellulose as a bio-leather and using it as a dye adsorbent

Owing to its sustainability and environmentally friendliness, bacterial cellulose (BC) has received attention as a zero-waste textile material. Since the color of original BC was mostly yellowish white, a dyeing process is necessary to suggest BC as a textile. Thus, this study aimed to suggest a natural dyeing method using coffee to produce an eco-friendly coffee-dyed bacterial cellulose (BC-COF) bio-leather and to propose a reusing method as a dye adsorbent. To determine the dyeing and mordanting conditions with the highest color strength value, parameters such as dyeing temperature, time, mordanting methods were evaluated. Fourier-transform infrared spectroscopy and X-ray diffraction analysis confirmed that BC-COF was successfully colorized with coffee without changing its chemical and crystalline structures. In addition, field-emission scanning electron microscopy and Brunauer-Emmett-Teller surface area analysis confirmed that coffee molecules were successfully incorporated into fiber structures of BC. The effects of pH, concentration, temperature, and time on the adsorption of methylene blue dye using BC-COF bio-leather were also evaluated using ultraviolet-visible spectroscopy and zeta potential measurement. The results showed that BC-COF was found to be most effective when pH 6 of methylene blue solution with a concentration of 50 mg/L was adsorbed for 30 minutes at 25°C. Moreover, BC-COF could be reused for multiple times and had better dye adsorption rate compared to the original BC. From the results, it was confirmed that BC-COF could be employed as a dye adsorbent.

Global Perspective of Plant-Based Cosmetic Industry and Possible Contribution of Sri Lanka to the Development of Herbal Cosmetics

The global consumption of plant-based cosmetics has shown spectacular growth in recent years because of rising consumer awareness regarding the long-term health benefits of natural ingredients. As the global demand for herbal cosmetics increases, there are ample opportunities for Sri Lanka as a tropical Asian country to expand its productions and global exports along with its unique biodiversity and inherited traditional knowledge. Therefore, the present review attempts to give an overview of the widely used medicinal plants in the global herbal cosmetic industry and strengths, challenges, and possible solutions for the development of the herbal cosmetic industry of Sri Lanka. Information was collected using electronic search (using Pub Med, Science Direct, Web of Science, Google Scholar, TEEAL, and Scopus) for articles published in peer-reviewed journals, industrial reports, market surveys, and library search for local books on ethnobotany. Important plant-derived ingredients used in the global herbal cosmetic industry are essential oils, colorants, oils, fats, and waxes. The traditional usage of 108 medicinal plant species (belonging to 58 families) in cosmetic treatments was identified from the local books of Sri Lanka. Of these, 49 plant species were reported as new ingredients for the herbal cosmetic industry. However, the lack of ethnobotanical and ethnopharmacological surveys to identify the cosmetic potential plants, insufficient or absence of continuous supply of raw materials for production in line with the existing demand, the lack of quality control of raw materials and finished cosmetic products, improper systematic cultivation systems for medicinal plants, poor postharvest practices, and the lack of innovations are major challenges encountered in Sri Lanka for the development of the herbal cosmetic industry. In conclusion, addressing these vital knowledge gaps is a timely requirement of the country for the sustainable development of the herbal cosmetic industry in Sri Lanka. Furthermore, assembling of the multidisciplinary cooperation of botanists, chemists, toxicologists, researchers, and biologists is crucial to analyze the interesting functional properties, efficacy, and effectiveness of documented medicinal plants with cosmetic potential.

Application of Achillea millefolium extract as a reducing agent for synthesis of silver nanoparticles (AgNPs) on the cotton: antibacterial, antioxidant and dyeing studies

The phyto-synthesis of silver nanoparticles and cotton dyeing with natural colorants can reduce the environmental impact of the process considerably. In this study, the extraction of natural colorants from Achillea millefolium petals was optimized by ultrasound technique. The AMP extract was applied for synthesis of silver nanoparticles (Ag NPs) on the cotton fabrics. The dyeing, antibacterial and antioxidant characteristics of cotton samples were investigated to optimize the process and evaluate its efficiency. The AMP extract had good substantivity towards cotton fabrics and the presence of tannic acid, as an environmentally-friendly mordant, further improved the absorption of AMP dye. The antibacterial and antioxidant activities of the dyed samples with AMP extract of were 50%and 60%, respectively. The addition of TA and Ag enhanced the antibacterial and antioxidant activities on the cotton samples to over 99%.

Flower Extracts as Multifunctional Dyes in the Cosmetics Industry

Flowers are a natural source of bioactive compounds that not only have antioxidant, anti-inflammatory, and anti-aging properties, but can also be used as natural dyes. For this reason, nowadays plants are widely used to produce natural cosmetics and foods. In these studies, the properties of the water extracts of Papaver rhoeas L., Punica granatum L., Clitoria ternatea L., Carthamus tinctorius L., and Gomphrena globosa L., as bioactive, natural dyes, were investigated. Plant flower extracts were tested for their antioxidant (ABTS and DPPH radical methods) and anti-inflammatory effects by determining the ability to inhibit the activity of lipoxygenase and proteinase. The extracts were tested for their cytotoxic effect on skin cells, using Alamar Blue and Neutral Red tests. The ability to inhibit the activity of enzymes responsible for the destruction of elastin and collagen was also studied. Research has shown that extracts have no toxic effect on skin cells, are a rich source of antioxidants and show the ability to inhibit the activity of elastase and collagenase enzymes. P. rhoeas extract showed the strongest antioxidant properties with IC50 value of 24.8 ± 0.42 µg/mL and 47.5 ± 1.01 µg/mL in ABTS and DPPH tests, respectively. The tested plants are also characterized by an anti-inflammatory property, for which the ability to inhibit lipoxygenase at a level above 80% and proteinase at the level of about 55% was noted. Extracts from P. rhoeas, C. ternatea, and C. tinctorius show the strongest coloring ability and can permanently dye cosmetic products, without significant color changes during the storage of the product.

Actinomycin X2, an Antimicrobial Depsipeptide from Marine-Derived Streptomyces cyaneofuscatus Applied as a Good Natural Dye for Silk Fabric

Actinomycins as clinical medicine have been extensively studied, while few investigations were conducted to discover the feasibility of actinomycins as antimicrobial natural dye contributing to the medical value of the functional fabrics. This study was focused on the application of actinomycin X2 (Ac.X2), a peptide pigment cultured from marine-derived Streptomyces cyaneofuscatus, in the dyeing and finishing of silk fabric. The dyeing potential of Ac.X2 with silk vs. cotton fabrics was assessed. As a result, the silk fabric exhibited greater uptake and color fastness with Ac.X2. Through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses, some changes of chemical property for the dyed fabric and Ac.X2 were studied. The silk fabric dyed with Ac.X2 exhibited good UV protection ability. The antibacterial properties of dyed and finished silk were also evaluated, which exhibited over 90% antibacterial activity even after 20 washing cycles. In addition, the brine shrimp assay was conducted to evaluate the general toxicity of the tested fabric, and the results indicated that the dyed silk fabrics had a good biological safety property.