Search

A subject of great interest is the bioprospecting of microorganisms and their bioactive byproducts, such as pigments. Microbial pigments have various benefits, including being safe to use due to their natural makeup, having therapeutic effects, and being produced all year round, regardless of the weather or location. Pseudomonas aeruginosa produces phenazine pigments that are crucial for interactions between Pseudomonas species and other living things. Pyocyanin pigment, which is synthesized by 90–95% of P. aeruginosa, has potent antibacterial, antioxidant, and anticancer properties. Herein, we will concentrate on the production and extraction of pyocyanin pigment and its biological use in different areas of biotechnology, engineering, and biology. [ABSTRACT FROM AUTHOR]

Bacterial pigments are the wonder molecules of nature that have attracted the attention of industries in recent years. To date, various synthetic pigments have been in use in food, cosmetics, and textile industries that have not only shown a notoriously toxic nature but also posed threat to the ecosystem. Moreover, nutraceuticals, fisheries, and animal husbandry were highly dependent on plant sources for products that aid in disease prevention and improve stock health. In this context, the use of bacterial pigments as new-generation colorants, food fortifiers, and supplements can hold great prospects as low-cost, healthy, and eco-friendly alternatives. The majority of studies on these compounds were restricted to antimicrobial, antioxidant, and anticancer potentials to date. Each of these can be highly beneficial for the development of new-generation drugs, but their other potential niche in various industries that pose health and environmental risks needs to be explored. Recent advances in novel strategies of metabolic engineering, advancements in optimization tools for the fermentation process, and the design of appropriate delivery systems will greatly expand the market of bacterial pigments in industries. This review summarizes the current technologies for enhancing production, recovery, stability, and appreciable use of bacterial pigments in industries apart from therapeutics with proper financial aspects. The toxicity perspectives have been focused to emphasize that these wonder molecules are the need of the hour and their future prospects have been highlighted. Extensive literature has been studied to include the challenges of bacterial pigments from environmental and health risk perspectives. [Display omitted] • Role of pigments and need of bio-pigment for health and environmental safety. • Bacterial pigments as an alternative to commercial toxic dyes. • A good source of stock color enhancer in fisheries and animal husbandry. • Current upstream and downstream strategies to enhance its production and stability. • Industrial market and environmental risk aspects of bacterial pigments. [ABSTRACT FROM AUTHOR]

In this study, needleless electrospinning technology was used to obtain flexirubin (F)‐loaded polyvinyl alcohol (PVA)_kefiran (KF)/polycaprolactone (PCL) electrospun nanofibers. The SEM images of PVA_KF_ F and PCL_F nanofibers displayed beadless morphology with average diameters of 211.90 ± 96.08 and 1610.71 ± 996.68 nm, respectively. FTIR‐ATR analysis revealed increased intensity at specific wavelengths, after pigment incorporation. The high porosity exhibited by each layer and the mechanical properties of the double‐layered nanofibrous material remained unaffected after flexirubin‐type pigment incorporation. In addition, PVA_KF_F/PCL_F nanofibers showed antioxidant activity of 41.03 ± 0.29%, evaluated by the scavenging of the ABTS radical as well as the ability to reduce enzymatic browning of apple slices. Thus, we believe that the fabricated PVA_KF_F/PCL_F double‐layered material can be considered for application in active food packaging systems. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pigments from natural sources, such as bacterial pigments, have gained increased attention in recent years due to their biodegradability, non-toxicity, and noncarcinogenicity. The intention to replace synthetic and oil-derived compounds is not restricted to synthetic dyes; other applications include the replacement of oilderived polymers for more environmentally friendly options, such as biopolymers. In this work, the functionalization of a bacterial cellulose (BC) biopolymer with bacterial pigments was explored using a full factorial design methodology to evaluate the best functionalization conditions to produce colored BC. From the factors and interactions evaluated, it was possible to conclude that the variable duration of the functionalization procedure could be reduced to a low level without significantly affecting the functionalization of the BC samples with bacterial pigments. Moreover, BC is a product with high industrial applicability, versatility, and sustainability. Hence, the multifunctional colored BC can be applied in the packaging, paper, and textile industries, among others. [ABSTRACT FROM AUTHOR]

Among 46 local bacterial isolates capable synthetized pigments, 26% produced extracellular of blue green and fluorescent whereas 74% produced intra-cellular pigments of red, brown, yellow, orange, and rose. Seven isolates were selected as a potential candidate for the synthesis of pigments. They were Pseudomonas fluoresces, P. aeruginosa, Serratia marcescens, Azotobacter chroococcum, Micrococcus kristinae, M. luteus, and M. roseus after their morphological and biochemical studies. They capable to produce fluorescent, blue green, red, brown, orange, yellow, and rose with maximum absorbance at 400, 520, 530, 320, 440, 460, and 470 nm, with an optical density of 0.62, 1.42,1.35, 1.11, 0.45, 0.98, and 0.40, respectively. Antibacterial activity of pigments was studied against 7 bacterial pathogenic strains namely P. aeruginosa ATCC27853, Escherichia coli 0157h7 ATCC25922, Klebsiella pneumoniae ATCC00607, Salmonella typhimurium ATCC25566, Listeria monocytogenes ATCC19115, Staphylococcus aureus ATCC29737, and Bacillus cereus ATCC33018. The last tested strain behaved high significant (p≤ 0.05) sensitivity for blue green, fluorescent, brown, and rose pigments while, L. monocytogenes ATCC19115 was more susceptible for red, and yellow pigments and S. aureus ATCC29737 had more inhibited by orange pigment. These bacterial pigments seemed to have antioxidant activity which inhibited the formation of diphenyl-2-picrylhydrazyl radicals with percentage ranged from 40 % to 80 %. It could therefore be stated that the bacterial pigments tested had a broad impact on foodborne pathogens and had an antioxidant effect. [ABSTRACT FROM AUTHOR]

Pigments are light-absorbing substances that are abundant in nature, serving roles in coloration, camouflage, mate/pollinator attraction and photosynthesis among higher life forms. Among microbial organisms, pigments can also be found in a wide range of phyla. While some of these pigments function in photosynthesis, namely among algae and some bacteria, the great majority of microbial pigments play entirely different roles. The exploratory study presented here will stimulate students to think about the cost and benefit of a heritable trait (pigment production) of microscopic organisms and its effects on survival in a competitive and hostile environment. Exploring and understanding the roles these pigments play allows for a number of cross-disciplinary learning opportunities that combine physics, chemistry, biology and even art, and can be set up as an inquiry-based learning module suitable for small-group and active learning experiences. [ABSTRACT FROM AUTHOR]

Abstract As a kind of natural dye, microbial pigments are attracting more and more attention for their application in textile dyeing. In this study, prodigiosins suspension produced by fermentation of Serratia marcescens was utilized as a novel kind of cleaner dye liquor for silk fabric dyeing. The average particle size of pigment particles was 217.1 nm and the prodigiosins concentration was determined to be 69.38 mg/L. Effects of technical parameters including dyeing temperature, dyeing time and dye liquor pH on dyeing effect and antibacterial capability of dyed fabrics were explored. The results indicated that when the dyeing temperature was 80 °C with a holding time of 30 min, dyed silk under dye bath pH 2.1 possessed high color strength, good color fastness and outstanding bacteriostatic rate of above 93.0% against Staphylococcus aureus. In addition, in vitro cytocompatibility test indicated that dyed silk fabric had no potential cytotoxicity to L929 cells. This study provided an innovative clean approach of dyeing silk with prodigiosins and endowed the fabric with antibacterial activity, simultaneously. Graphical abstract Image Highlights • Prodigiosins suspension produced by liquid fermentation is utilized as a kind of cleaner natural dye for silk fabric dyeing. • Influences of dyeing temperature, time and dye bath pH on dyeing effect are investigated. • Dyed silk fabric possesses excellent antimicrobial activity against S. aureus and good cytocompatibility with L929 cells. [ABSTRACT FROM AUTHOR]

Spray drying is one of the well-established one-step processes of encapsulation technique to form micro particles. The concentrated violet pigment produced from Chromobacterium violaceum UTM 5 was encapsulated using Gum Arabic and spray dried under optimum conditions: atomizing air (1.15 kg/cm 3 ), temperature feed rate (30 °C), air flow rate (60 m 3 /h), inlet (180 °C) and outlet (85 °C) temperatures to produce violet powder. On further investigation, the encapsulated pigment exhibited greatest stability during the entire storage period of 30 days at pH 7, temperature 25–60 °C and under dark condition. The violet powders produced were utilized in coloring food products, yogurt and jelly. Results confirmed promising use of this healthy natural colorant in food industry. This is the first report on spray drying of violet pigment from Chromobacterium violaceum and its potential for application in food items. [ABSTRACT FROM AUTHOR]

Highlights: [•] Bacterial pigments in terms of current trends, market needs and economics. [•] Technological challenges in bacterial pigment production processes. [•] Novel strategies for production of bacterial pigments. [•] Application of bacterial pigments in food, pharmaceuticals, dyeing and other aspects. [Copyright &y& Elsevier]

Abstract: The phototrophic communities in meromictic, perennially ice-covered Lake A, on Ellesmere Island in the Canadian High Arctic, were characterized by pigment analysis using high performance liquid chromatography. Samples were taken to determine the vertical changes down the water column as well as a variation between years. These analyses showed that Lake A had distinct phototrophic communities in its oxic and anoxic layers. The pigment analyses indicated that phototrophic biomass in the upper, oxic waters was dominated by picocyanobacteria, while in the lower, anoxic layer photosynthetic green sulphur bacteria were dominant. Interannual variation in pigment concentrations was related to the penetration of photosynthetically active radiation in the water column, suggesting that light availability may be limiting the net accumulation of photosynthetic bacterial biomass in Lake A. Pigment analysis of the surface sediments indicated that deposition was dominated by the photosynthetic sulphur bacterial contribution. The sedimentary record of bacterial pigments in polar meromictic lakes offers a promising tool for the reconstruction of past changes in ice cover and therefore in climate. [Copyright &y& Elsevier]

Nowadays, food packaging systems have shifted from a passive to an active role in which the incorporation of antimicrobial compounds into biopolymers can promote a sustainable way to reduce food spoilage and its environmental impact. Accordingly, composite materials based on oxidized-bacterial cellulose (BC) and poly(vinyl alcohol)-chitosan (PVA-CH) nanofibers were produced by needleless electrospinning and functionalized with the bacterial pigment prodigiosin (PG). Two strategies were explored, in the first approach PG was incorporated in the electrospun PVA-CH layer, and TEMPO-oxidized BC was the substrate for nanofibers deposition (BC/PVA-CH_PG composite). In the second approach, TEMPO-oxidized BC was functionalized with PG, and afterward, the PVA-CH layer was electrospun (BC_PG/PVA-CH composite). The double-layer composites obtained were characterized and the nanofibrous layers displayed smooth fibers with average diameters of 139.63 ± 65.52 nm and 140.17 ± 57.04 nm, with and without pigment incorporation, respectively. FTIR-ATR analysis confirmed BC oxidation and revealed increased intensity at specific wavelengths, after pigment incorporation. Moreover, the moderate hydrophilic behavior, as well as the high porosity exhibited by each layer, remained mostly unaffected after PG incorporation. The composites' mechanical performance and the water vapor transmission rate (WVTR) evaluation indicated the suitability of the materials for certain food packaging solutions, especially for fresh products. Additionally, the red color provided by the bacterial pigment PG on the external surface of a food packaging material is also a desirable effect, to attract the consumers' attention, creating a multifunctional material. Furthermore, the antimicrobial activity was evaluated and, PVA-CH_PG, and BC_PG layers exhibited the highest antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Thus, the fabricated composites can be considered for application in active food packaging, owing to PG antimicrobial potential, to prevent foodborne pathogens (with PG incorporated into the inner layer of the food packaging material, BC/PVA-CH_PG composite), but also to prevent external contamination, by tackling the exterior of food packaging materials (with PG added to the outer layer, BC_PG/PVA-CH composite). [ABSTRACT FROM AUTHOR]

Microorganisms are considered one of the most promising niches for prospecting, production, and application of bioactive compounds of biotechnological interest. Among them, bacteria offer certain distinctive advantages due to their short life cycle, their low sensitivity to seasonal and climatic changes, their easy scaling as well as their ability to produce pigments of various colors and shades. Natural pigments have attracted the attention of industry due to an increasing interest in the generation of new products harmless to humans and nature. This is because pigments of artificial origin used in industry can have various deleterious effects. On this basis, bacterial pigments promise to be an attractive niche of new biotechnological applications, from functional food production to the generation of new drugs and biomedical therapies. This review endeavors to establish the beneficial properties of several relevant pigments of bacterial origin and their relation to applications in the biomedical area. [ABSTRACT FROM AUTHOR]

Prodigiosin, a natural pigment produced as a secondary metabolite by the non-photosynthetic bacterium Serratia marcescens , was tested as a sensitizer in dye-sensitized solar cells (DSSC). The strain S. marcescens 11E, which was isolated from a natural spring located in the northeastern Mexican state of Nuevo Leon, was cultivated on peanut oil broth 1% v/v, a culture medium which is known to enhance the production of prodigiosin. The resulting pigment was extracted with chloroform and identified as prodigiosin based on the spectroscopic and structural characteristics obtained by UV–Vis spectrophotometry along with FTIR and 1H NMR spectroscopies. The initial absorbance decomposition test performed on the bacterial pigment demonstrated that prodigiosin exhibited high photostability after five days, while the photovoltaic performance test of the sensitized DSSC, resulted in an open voltage circuit of 560 mV, a current density of 0.096 mA/cm2, and efficiency of 0.032%. Structurally, the DSSC consisted of a titanium dioxide (TiO 2) photoanode sensitized with the pigment by direct adsorption, an electrolyte containing a redox pair I−/I3− and a cathode or counter electrode prepared from a carbon paste. Since the overproduction of prodigiosin can be easily achieved on a large scale through the rapid fermentation of agro-industrial residues throughout the year without the need to allocate surfaces for the cultivation of pigment-producing plants or wait for specific seasons for their cultivation, our results suggest that prodigiosin could be considered an excellent candidate to be used in the development of a low-tech, low-cost DSSC. • Application of prodigiosin pigment in dye-sensitized solar cells (DSSCs). • High photostability of prodigiosin over 5 days exposed to light. • Low-cost DSSC using carbon paste as counter electrode and TiO 2 /Prodigiosin as anode. [ABSTRACT FROM AUTHOR]

Summary Pigmentation is a fundamental characteristic of living organisms that is used to absorb radiation energy and to regulate temperature. Since darker pigments absorb more radiation than lighter ones, they stream more heat, which can provide an adaptive advantage at higher latitudes and a disadvantage near the Tropics, because of the risk of overheating. This intuitive process of color-mediated thermoregulation, also known as the theory of thermal melanism (TTM), has been only tested in ectothermic animal models [ 1–8 ]. Here, we report an association between yeast pigmentation and their latitude of isolation, with dark-pigmented isolates being more frequent away from the Tropics. To measure the impact of microbial pigmentation in energy capture from radiation, we generated 20 pigmented variants of Cryptococcus neoformans and Candida spp. Infrared thermography revealed that dark-pigmented yeasts heated up faster and reached higher temperatures (up to 2-fold) than lighter ones following irradiation. Melanin-pigmented C. neoformans exhibited a growth advantage relative to non-melanized yeasts when incubated under the light at 4°C but increased thermal susceptibility at 25°C ambient temperatures. Our results extend the TTM to microbiology and suggest pigmentation as an ancient adaptation mechanism for gaining thermal energy from radiation. The contribution of microbial pigmentation in heat absorption is relevant to microbial ecology and for estimating global temperatures. The color variations available in yeasts provide new opportunities in chromatology to quantify radiative heat transfer and validate biophysical models of heat flow [ 9 ] that are not possible with plants or animals. [ABSTRACT FROM AUTHOR]

Review: 52 refs. [ABSTRACT FROM AUTHOR]