Microalgae Pigments Research Articles

The effect of temperature and encapsulation on the stability of microalgae pigments

Microalgae pigments are gaining interest in food industry applications as food additives by providing color and health benefits such as antioxidant properties. The pigment’s sensitivity to heat, pH, oxygen, and other conditions may reduce or lose its function in food products. Due to the sensitivity and instability of microalgae pigment, strategies are needed to protect and retain pigment from reducing their functions. Thirty-two research papers related to the topic published during 2012-2022 were employed in the review. This review focuses on astaxanthin from Haematococcus pluvialis, phycocyanin from Spirulina platensis, and β-Carotene from Dunaliella salina, as widely known microalgae pigments. This paper provides information about the effect of temperature during processing and storage on the stability of the pigments. Strategies to improve pigment stability by encapsulation were also discussed. The study concluded that temperature is one of the essential factors that affects microalgae stability. Furthermore, encapsulation may provide a potential solution to protect and maintain the stability of microalgae pigments.

The Characteristic Of Biocomposite Film Of Spirulina Residue As Natural Dyes

Spirulina plantesis microalgae contain active ingredients in the form of antioxidants and pigments. Currently, the microalgae Spirulina plantesis is used as an antioxidant in the food, pharmaceutical and cosmetic industries. This manuscript discusses the utilization of Spirulina plantesis microalgae pigment as a natural dye plastic. The need for color plastics for various uses continues to increase. The use of natural dyes for plastics is expected to produce biocomposite films that are safe for the environment or biodegradable and safe to be used. The aim of the study was to determine the effect of adding Spirulina residue as a natural dye on the characteristics of biocomposite films. The variable concentration of Spirulina residue added to the biocomposite film formula was 0.5%,1%, and 1.5%. The film production method used was the solution casting method. In this study, 200ml of distilled water was added with Spirulina residue (SR), then stirred for 30 minutes, and after that successively added 1% Glycerol and stirred for 15 minutes; Carrageenan 1% and stirred for 15 minutes. The solution was heated at 70oC then Polyvinyl Alcohol (PVA) with concentrations of 3%, 4%, and 5%, and Tapioca (3%) were added until complete gelatinization occurred. The solution was poured into a 30 cm x 20 cm mold and dried at 30oC for 48 hours to form a film. Biocomposite films were analyzed for tensile strength and elongation at break based on ASTM D 638, color, and morphology. The results showed that the highest tensile strength and elongation at break of biocomposites were found in biocomposite films with the addition of 0.5% Spirulina residue, namely 96.40±6.04 kgf/m2 and 47.64±7.48%, respectively. Analysis of the color of the biocomposite films showed the highest greenish and yellowish colors in the biocomposite films with the addition of 1.5% Spirulina residue and 5% PVA. Spirulina residue can be utilized as the plastic dyes.

Dynamical Darwinian selection of a more productive strain of Tisochrysis lutea

Species domestication and improvement were decisive in increasing agricultural production yields. The microalgae industry must now realize the same accomplishment to boost its development instead of only using wild strains. Although genetically engineering microalgae is a promising path to explore, the artificial modification of the microalgae genome can have adverse side-effects on biomass productivity. Here, we propose a Darwinian method to select and improve microalgal strains, exploiting the competitive exclusion principle in a dynamical environment to drive evolution. Choosing an appropriate selection pressure allows a new adapted population having enhanced properties to emerge. In a natural growing environment, light intensity is consistently changing due to meteorological events, differing microalgae concentration and other exogenous factors. Consequently, the pigmentary profile regulation and the associated genetic mechanism is highly modulable in most microalgae. On top of this, high light intensities are known to elicit strong cellular stresses. For these reasons, a dynamical light regime with high light intensities was deemed a potentially efficient selection factor for the emergence of a new strain adapted to higher irradiance levels. Following 160 days of selection under variable light intensity the biomass productivity of Tisochrysis lutea increased by 77%. Genetic analyses further confirmed the selection protocol's success, with the apparition of 2716 new alleles. To our knowledge, this is the first selection approach allowing a significant biomass productivity increase resulting from an enhanced capacity of microalgae pigment photoadaptation.

Microalgae pigments as a promising immunomodulating food ingredient: In silico study

Microalgae pigments attract the commercial market as functional food ingredients because of their potential as an antioxidant and anti-inflammatory agents. Through in vitro and in vivo studies, microalgae pigments showed a potential therapeutic effect to reduce the expression of pro-inflammatory cytokines by inhibiting inflammation signaling. Our study explored the potency of microalgae pigments as an immunomodulator by modeling the direct interaction between pigments and pro-inflammatory proteins by molecular docking. The docking study was carried out using AutoDock Vina. At the same time, the binding visualization was obtained by using Discovery Studio Visualizer. The result showed all investigated microalgae pigments (i.e., phycocyanobilin, astaxanthin, β-carotene, 9-cis- (β-carotene, and violaxanthin) docked to pro-inflammatory proteins (i.e., IL-6, TNF-α, and NIK), respectively in various binding energy. The binding between pigment compounds and the target protein is mostly attributed to the Van der Waals interaction. Notably, the pigments docked in crucial residues in proinflammatory proteins, suggesting the effect of the protein interaction on its receptor and cytokines activity. The results showed a therapeutic potency of microalgae pigment to support immune system modulation that could prevent and attenuate chronic inflammation.

Enhancing Algae Biomass Production by Using Dye-Sensitized Solar Cells as Filters

One of the most promising options for decreasing the costs of microalgae production is enhancing the production and reducing the energy demand of the culturing systems and the high surface area requirements. Because microalgae growth requires only specific wavelengths of the solar spectrum, the remaining part of the solar spectrum may be simultaneously used by a translucent photovoltaic (PV) layer to produce electricity, which leads to a reduction of space and energy requirements. This work presents the results of a new concept of a positive energy culturing system for microalgae, where the light source is selectively shared between the needs of the algal biomass through photosynthesis and the production of PV energy through dye-sensitized solar cells (DSCs). To ascertain the DSC (DSC-Red, DSC-Green) light-filtering effects on microalgal biomass, (1) the variation of growth kinetics, (2) microalgae pigments [chlorophylls-(a + b) and carotenoids], and (3) macromolecule content (carbohydrates, proteins, and lipids) were investigated and compared to control cultures under two different solar-simulated light intensities (200 and 600 W/m2). The results showed a net improvement of the growth rate and dry weight at the higher irradiance using both colored DSC filters compared to control cultures. The highest growth rates (μ) and doubling time (td) of Chlorella vulgaris cells were obtained using the DSC-Red (DSC-R) and DSC-Green (DSC-G) solar cells as filters with μ = 0.86 ± 0.01 day–1; td = 0.80 day and μ = 0.85 ± 0.03 day–1; td = 0.81 day, respectively, compared to normal glass control μ = 0.51 ± 0.03 day–1; td = 1.35 day. A significant increase in the chlorophyll-a content was obtained under low light intensity for both DSC-colored compared to control culture, and there was no significant variation in the macromolecule content measured under the tested light intensities. Finally, a life cycle assessment based on a functional unit of 1 kg of the produced algal biomass using the DSC–photobioreactor (DSC–PBR) was performed and compared to a normal glass PBR. The results were expressed in terms of CO2 emission equivalents produced and electricity generated. A fraction of electricity generated by DSC–PBR is used for bubbling, and the extra electricity is injected into the electricity grid. This resulted in net negative GHG emissions.

Pigment analysis based on a line-scanning fluorescence hyperspectral imaging microscope combined with multivariate curve resolution.

A rapid and cost-effective system is vital for the detection of harmful algae that causes environmental problems in terms of water quality. The approach for algae detection was to capture images based on hyperspectral fluorescence imaging microscope by detecting specific fluorescence signatures. With the high degree of overlapping spectra of algae, the distribution of pigment in the region of interest was unknown according to a previous report. We propose an optimization method of multivariate curve resolution (MCR) to improve the performance of pigment analysis. The reconstruction image described location and concentration of the microalgae pigments. This result indicated the cyanobacterial pigment distribution and mapped the relative pigment content. In conclusion, with the advantage of acquiring two-dimensional images across a range of spectra, HSI conjoining spectral features with spatial information efficiently estimated specific features of harmful microalgae in MCR models.

Microalgae-enriched breadsticks: Analysis for vitamin C, carotenoids, and chlorophyll a

Microalgae are a potential ingredient that can enhance the nutritional value of food. There are already various products made from microalgae such as pasta, cookies, breadstick, crackers, and extrudates. Moreover, these products have a typical green colour, provided from microalgae pigments. This study aimed to evaluate the effect of the addition of Chlorella vulgaris and Arthrospira platensis biomass on vitamin C, total carotenoids, and chlorophyll a levels in breadsticks and its doughs. Microalgae addition in breadstick formulations is a viable alternative, because they presented a greater content of carotenoids and chlorophyll a than control breadsticks. Consequently, microalgae enriched breadsticks can provide health benefits to consumers. Here, Chlorella enriched breadsticks showed the highest studied pigments content. Despite microalgae powder containing vitamin C, breadstick dough did not present vitamin C and therefore nor the breadstick.

Understanding the toxicity effect and mineralization efficiency of in-situ electrogenerated chlorine dioxide for the treatment of priority pollutants of coking wastewater

Oxidation of phenol, cyanide and aniline have been analyzed by the enhanced electro-oxidation process in which sodium chlorite was used as an electrolyte and results were validated using statistical tool based on Box-Behnken design. The mineralization efficiency of 78.4%, and 98.18% were predicted at optimized variables condition for phenol, and aniline respectively, whereas complete mineralization has been observed for the cyanide at the optimized conditions, which describes the significance of the design model approach.The process mineralizes the higher phenol concentration revealing a drastic reduction in power consumption in comparison of direct oxidation, i.e., 799.36 kWh/kg to 138.18 kWh/kg for more than 90% mineralization of phenol even at a higher current density of 13.63 mA/cm2. The kinetic modelling approach justified that higher current density has also played a role in higher mineralization of pollutants at the specific operating conditions. The by-product formation and toxicity effect on microalgae in wastewater were assessed by the full scan mass spectrometry and microalgae pigment inhibition test after the electro-oxidation of coking wastewater. The pigment growth inhibition rate of Chlorella sp. NCQ and Micractinium sp. NCS2 suggests that sodium chlorite as an electrolyte aid can also effectively used as an oxidizing agent and algal inhibiter in the coking wastewater.

(Bio)Technological aspects of microalgae pigments for cosmetics.

Photosynthetic microorganisms convert carbon dioxide and solar radiation into interesting bioactive compounds not yet entirely explored. Several species of microalgae are known to be rich in colored high-valuable components that, although remarkable, are poorly explored as natural sources of pigments for cosmetics. Pigments associated to photosynthetic activity include chlorophyll, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins, many of which have shown high potential as cosmetic actives due to their antioxidant, immune-enhancing, and anti-inflammatory properties. In the last decade, concern with a young and beautiful appearance has emerged, encouraging many consumers to use anti-aging cosmetics daily. As a result, the cosmetic market has been growing and evolving rapidly to meet consumer expectations. However, due to regular use and the sensitive nature of facial skin, local adverse reactions may often occur, such as irritation, sensitization, or photoreactions, and safety evaluation is mandatory prior to marketing. It is, therefore, understandable that new actives from natural sources, such as microalgae, are perceived as attractive alternatives for consumers who seek ingredients without allergenic potential. Thus, the cosmetic industry has recently started to explore the inclusion of compounds extracted from microalgae and cyanobacteria in innovative formulations. Herein, we revised nontraditional microalgae species for pigment production with cosmetic applications, indicating those that could also be considered potential ingredients for innovative cosmetics. KEY POINTS: • Extraction methods for pigments from photosynthetic microorganisms were compiled. • Innovative cosmeceuticals could be developed with natural pigments. • Safety features of such natural pigments were also described.

HPLC-PDA-MS/MS as a strategy to characterize and quantify natural pigments from microalgae

Interest in pigment composition of microalgae species is growing as new natural pigments sources are being sought. However, we still have a limited number of species of microalgae exploited to obtain these compounds. Considering these facts, the detailed composition of carotenoids and chlorophylls of two species of green microalgae (Chlorella sorokiniana and Scenedesmus bijuga) were determined for the first time by high-performance liquid chromatography coupled to diode array and mass spectrometry detectors (HPLC-PDA-MS/MS). A total of 17 different carotenoids were separated in all the extracts. Most of the carotenoids present in the two microalgae species are xanthophylls. C. sorokiniana presented 11 carotenoids (1408.46 μg g−1), and S. bijuga showed 16 carotenoids (1195.75 μg g−1). The main carotenoids detected in the two microalgae were all-trans-lutein and all-trans-β-carotene. All-trans-lutein was substantially higher in C. sorokiniana (59.01%), whereas all-trans-β-carotene was detected in higher quantitative values in S. bijuga (13.88%). Seven chlorophyll compounds were identified in both strains with different proportions in each species. Concentrations of chlorophyll representing 7.6% and 10.2% of the composition of the compounds present in the biomass of C. sorokiniana and S. bijuga, respectively. Relevant chlorophyll compounds are reported for the first time in these strains. The data obtained provide significant insights for microalgae pigment composition databases.

Production of O/W Emulsions Containing Astaxanthin by Microfluidic Devices

Astaxanthin is a fat soluble ketocarotenoid whose biological functions are formed by its high antioxidant activity, which makes its use promising in the pharmaceutical, cosmetic, food, and feed industries. However, the unstable structure of astaxanthin significantly limits its use. We study the possibility of using a microfluidic system to obtain stable oil-in-water (O/W) emulsions, the oil phase of which contains the Haematococcus pluvialis IPPASH-629 microalgae pigments, the main component of which is astaxanthin in the free or esterified form. It is shown that the pigment composition of the oil phase affects both the size distribution of the emulsion droplets and stability. The emulsion containing the total H. pluvialis microalgae carotenoids, mainly astaxanthin monoesters, is characterized by a high degree of encapsulation, the highest degree of polydispersity, and the fact that the astaxanthin content after 56 days of storage at room temperature remains almost unchanged.

Identification of pesticide varieties by detecting characteristics of Chlorella pyrenoidosa using Visible/Near infrared hyperspectral imaging and Raman microspectroscopy technology

The main goal of this research is to examine the feasibility of applying Visible/Near-infrared hyperspectral imaging (Vis/NIR-HSI) and Raman microspectroscopy technology for non-destructive identification of pesticide varieties (glyphosate and butachlor). Both mentioned technologies were explored to investigate how internal elements or characteristics of Chlorella pyrenoidosa change when pesticides are applied, and in the meantime, to identify varieties of the pesticides during this procedure. Successive projections algorithm (SPA) was introduced to our study to identify seven most effective wavelengths. With those wavelengths suggested by SPA, a model of the linear discriminant analysis (LDA) was established to classify the pesticide varieties, and the correct classification rate of the SPA-LDA model reached as high as 100%. For the Raman technique, a few partial least squares discriminant analysis models were established with different preprocessing methods from which we also identified one processing approach that achieved the most optimal result. The sensitive wavelengths (SWs) which are related to algae's pigment were chosen, and a model of LDA was established with the correct identification reached a high level of 90.0%. The results showed that both Vis/NIR-HSI and Raman microspectroscopy techniques are capable to identify pesticide varieties in an indirect but effective way, and SPA is an effective wavelength extracting method. The SWs corresponding to microalgae pigments, which were influenced by pesticides, could also help to characterize different pesticide varieties and benefit the variety identification.

Towards the Clinical Use of Phytoplankton Carotenoid Pigments to Cure Cancer

Beyond their major ecolophysiological functions, phytoplankton pigments exert biological and pharmacological activities in human cells that allow considering their clinical use to cure various pathologies. Although much of our knowledge relating to their cell pharmacology and bioactivity has come from in vitro studies in cell culture models, recent in vivo studies have validated the potential of phytoplankton carotenoid pigments to limit inflammation and metabolic disorders, retinal diseases, degenerative diseases, tumor progression, and hepatotoxicity. Aside from these promising results, additional studies are now required to precise their pharmacokinetics, pharmacological targets, and clinical efficacy in humans. The availability of highly purified pigments at rational costs will be a milestone to set up clinical trials and develop new therapies using microalgae pigments. This short paper focuses on the great potential of phytoplankton carotenoid pigments to prevent and cure cancers. Marine and freshwater microalgae have evolved a wide range of pigments that belong to the chlorophylls, carotenoids and phycobiliproteins families. Extensive research has proved that microalgae pigments exert significant biological and pharmacological activities in human cells. Beyond their well-known antioxidant activity, used as a commercial argument to sell algae-based cosmetics and nutraceutics, it is now clearly established that microalgae pigments have a great potential as health nutrients to prevent cancer, as biotechnological probes for cancer diagnosis and as anticancer drugs to trigger cancer cells apoptosis, prevent tumor angiogenesis, reduce the risk of metastasis, sensitize cancer cells to chemotherapy, destroy cancer cells by tumor phototherapy and filter UV to limit cancer cells initiation. Numerous studies aiming to identify antiproliferative molecules from microalgae extracts led to the isolation of carotenoids and to the demonstration of their high antiproliferative, cytostatic, cytotoxic, and/or pro-apoptotic activity in cancer cell cultures [1,2]. As an example, our research team performed the bioguided isolation of pigments from Duniella tertiolecta and found that violaxanthin was the most antiproliferative molecule contained in Dt dichloromethane extract [3]. We also recently reported the strong antiproliferative activity of zeaxanthin and β-cryptoxanthin in human invasive melanoma cells, after their bioguided isolation from Cyanophora paradoxa ethanolic extracts [4].

Enhancement of Chlorella vulgaris Growth and Bioremediation Ability of Aquarium Wastewater Using Diazotrophs

Treatment of aquarium wastewater represents an important process to clean and recycle wastewater to be safely returned to the environment, used for cultivation or to minimize the multiple renewal of water. Chlorella vulgaris was an important freshwater microalgae which used in wastewater treatment, and increasing its potential of treatment can be achieved with existence of N2-fixing bacteria. Co-culturing of Chlorella vulgaris with the diazotrophs, Azospirillum brasilense or Azotobacter chroococcum in three different media; aquarium wastewater (AWW), sterile enriched natural aquarium wastewater (GPM) and synthetic wastewater media (SWW) were studied. Biomass yield of the microalgae was estimated by determination of chlorophylls (a and b), total carotenoid and the dry weight of C. vulgaris. Also determination of ammonia, nitrite, phosphate and nitrate in the culture were done. The presence of diazotrophs significantly increased the biomass of C. vulgaris by increasing its microalgae pigments (chlorophylls a and b, and total carotenoids). The highest pigments percentage was reported due to addition of A. brasilense to C. vulgaris (18.3-133.5%) compared to A. chroococcum (23.9-56.9%). As well as increased dry weight from 12 to 50%. There was also improved removal of nitrate, nitrite, ammonia and phosphate; where, the highest removal percentage was reported due to addition of A. chroococcum to C. vulgaris (0.0-52%) compared to A. brasilense (0.6-16.4%). A. brasilense and A. chroococcum can support C. vulgaris biomass production and bioremediation activity in the aquarium to minimize the periodical water renewal.