Microalgae as sustainable food and feed sources for animals and humans - Biotechnological and environmental aspects

Microfluidic method for rapidly determining the protein and lipid yield of microalgae

Microalgae are a promising source of green energy. They produce valuable bioproducts, such as proteins and lipids, and remove atmospheric carbon. In this study, we developed a microfluidic chip for culturing and screening for microalgae with high protein and lipid contents. Over 30 microalgae cultures can be grown in parallel in hanging drops on the chip and separately subjected to various experimental treatments, such as random mutations or different light levels. The microfluidic chip has a simple design and was fabricated from optically transparent polymethyl methacrylate; it could be easily operated without complex equipment (e.g., a syringe pump). The design was experimentally validated by culturing Cyanidium sp. and performing in-situ fluorescein measurements of its protein content after various ultraviolet and illumination treatments; significant increases in protein yield were observed for selected mutants (approximately 36 %) and further increased with optimized illumination (2500 lux; approximately 35 %). Moreover, Botryococcus braunii cultured in hanging drops that were separately immobilized using a biocompatible agarose gel for in-situ Raman spectroscopy measurements that rapidly determined the lipid composition. Our developed single-drop Raman spectroscopy method not only quantified the lipid content but also revealed its detailed chemical composition. In summary, the designed microfluidic chip is suitable for in-situ fluorescent assays and Raman microspectroscopy and is a compelling solution for high-throughput screening of algal lipids and proteins, reducing the labor required for breeding mutant algae and optimizing algal cultivation.

Effects of using microalgae in poultry diets on the production and quality of meat and eggs: a review

1. This review was conducted to examine the nutritional composition of microalgae and their effects as a feed ingredient in poultry diets, delving into their influence on the production and quality of meat and eggs. Data collection focused on peer-reviewed scientific articles, with no limitation on the temporal horizon.2. Regarding nutritional composition, the collected papers indicated that certain microalgae species have a rich nutritional composition, with approximately 50% of their biomass composed of proteins. They contain a high concentration of EPA and DHA, important fatty acids that are found in low concentrations in conventional feedstuffs, and the presence of carotenoids such as beta-carotene.3. Incorporating microalgae into the diet of poultry can improve performance variables, such as mortality, live weight and feed conversion rate. It promotes benefits in meat and egg quality, with reduced cholesterol, increased EPA and DHA, intensified colour and higher concentration of carotenoids.

P. Oliveira MB, Carpena M, Prieto MA. Therapeutic and Preventive Potential of Plant-Derived Antioxidant Nutraceuticals

Oxidative stress and its relation to the onset of several chronic diseases have been increasingly highlighted in recent years. In parallel, there has been an increasing interest in the antioxidant properties of phytochemicals. Phytochemicals are products of plant secondary metabolism, including structural polysaccharides, unsaturated fatty acids, pigments (chlorophylls, carotenoids, and anthocyanins), or phenolic compounds. Phytochemicals can be obtained from lower and higher plants, their fruits, and even from macro- or microalgae. Their diverse structural features are linked to different beneficial effects through various molecular mechanisms, contributing to disease prevention. Beyond antioxidant activity, many phytochemicals also display anti-inflammatory, antidiabetic, anti-obesity, and neuroprotective effects, which can be intertwined. Beyond these, other natural antioxidants can also be obtained from animal, fungal, and bacterial sources. Thus, a wide range of antioxidants have the potential to be used as nutraceuticals with chemopreventive effects on the onset of various diseases related to antioxidant stress. Given their enormous structural and sourcing diversity, the present work provides an updated insight into the therapeutic and preventive potential of plant-derived antioxidants and nutraceuticals.

Microalgae-mediated green synthesis of silver nanoparticles: a sustainable approach using extracellular polymeric substances from Graesiella emersonii KNUA204

Traditional nanoparticle synthesis relies on chemical and physical methods that often involve hazardous reagents, high energy consumption, and environmental toxicity. As a sustainable alternative, biological synthesis utilizes biomolecules in an eco-friendly manner to form nanoparticles. This study explores the green synthesis of silver nanoparticles (AgNPs) using extracellular polymeric substances (EPS) secreted by the microalga Graesiella emersonii KNUA204, highlighting the potential of microalgal biomolecules in nanotechnology. EPS-rich supernatant from G. emersonii enabled AgNP formation under light without the need for biomass pre-processing. The effects of culture age, pH (optimal at 10-11), and tetracycline as a secondary stabilizer were examined. Tetracycline accelerated AgNP formation in dark conditions but could not fully substitute light-induced reduction. The synthesized AgNPs and tetracycline-assisted AgNPs (Tetra-AgNPs) were characterized using UV-visible spectroscopy, EDX, XRD, FTIR, TEM, and Zeta potential measurements, confirming their crystalline, spherical, and moderately stable properties. Biological assays showed strong antibacterial activity at 10 μg mL-1, though Tetra-AgNPs did not outperform AgNPs or tetracycline alone, suggesting structural incorporation of tetracycline. Both AgNPs and Tetra-AgNPs showed similar antioxidant activity. These findings support the potential of G. emersonii KNUA204 for dual biomass utilization, integrating biofuel production with nanomaterial synthesis. Further optimization of EPS composition and biosynthesis conditions could enhance nanoparticle properties for biomedical and environmental applications, reinforcing microalgae as a platform for sustainable nanotechnology.

Complex interplay between the microalgae and their microbiome in production raceways

Algae-associated microbiomes are underexplored, limiting our understanding of their influence on the large-scale microalgae reactors. Over two 8-month periods, microbial dynamics were monitored three times per week in two microalgae raceways inoculated with Desmodesmus armatus. One reactor received wastewater, while the other used clean water and fertilizers. The sampled culture volume was filtered into pico and nano size fractions before DNA extraction. Metabarcoding of the 18S and 16S rRNA genes revealed a high microbial diversity across the two time series and a complex eukaryotic and prokaryotic community growing alongside the microalga. Chlorophyta and Fungi were the dominant eukaryotic groups, while Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Bacteroidia dominated the prokaryotic communities. Contrasting Amplicon Sequence Variants (ASVs) were found between healthy (D. armatus abundance > 70 %) and unhealthy (D. armatus abundance 10-20 %) conditions across reactors and time series. Network analysis identified up to 10 potential ecological interactions among D. armatus and its microbiome, predominantly positive. Specific ASVs associated with a healthy condition were positively correlated with D. armatus, while other ASVs linked to an unhealthy condition were negatively correlated. Potentially pathogenic bacteria included Mycobacterium and Flavobacterium, whereas potentially beneficial taxa included Geminocystis, Thiocapsa, Ahniella, and Bosea. Several fungal ASVs showed context-specific associations, whereas specific fungi such as Paraphelidium tribonemae, Aphelidium parallelum, Aphelidium desmodesmi, Aphelidiomycota sp., Rozellomycota sp., and Rhizophidium sp, were identified as potentially harmful. This study reveals the striking diversity and complexity of microalgae-associated microbiomes within raceways, providing valuable insights for optimizing industrial production processes, particularly for wastewater treatment and sustainable green biomass generation.

Marine Microalgae-Microorganism Co-Cultures: An Insight into Nannochloropsis sp. Use and Biotechnological Applications

The increasing demand for sustainable, economical, and environmentally friendly solutions has positioned microalgae as promising candidates in biotechnology, particularly in food, feed, nutraceutical, pharmaceutical, biofuel, and bioremediation applications. This review explores the role of the Nannochloropsis genus and other marine oleaginous microalgae in co-cultivation systems, highlighting their mechanisms of interaction with various microorganisms and their potential for various biotechnological purposes. Case studies of Nannochloropsis sp. co-cultures with other microalgae, bacteria, and fungi are presented. The different types of associations are described as alternative strategies to enhance biomass productivity, lipid accumulation, and nutrient recycling. A key focus of this review is the potential of Nannochloropsis microalgae co-cultivation in food, as it is part of the list of microalgae to be approved for consumption in the European Union, discussing their rich nutritional value, safety, and regulatory status. Additionally, the role of microalgae in the alternative protein sector is explored, with particular emphasis on their integration in cultivated meat products as nutrient suppliers and metabolic partners for animal cells. Despite their potential, several challenges, such as scale-up, contamination risk, and strain selection, remain key obstacles to the widespread adoption of microalgal biotechnology. Future research should focus on optimizing microalgae-based co-cultures for food applications, addressing safety concerns, and further investigating their integration into functional foods and cellular agriculture products.

Microalgae as an emerging alternative raw material of docosahexaenoic acid and eicosapentaenoic acid - a review

Long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been widely applied due to their nutraceutical and healthcare benefits. With the rising rates of chronic diseases, there is a growing consumer interest and demand for sustainable dietary sources of n-3 PUFAs. Currently, microalgae have emerged as a sustainable source of n-3 PUFAs which are rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), regarded as promising alternatives to conventional sources (seafood) that cannot meet the growing demands of natural food supplements. This review provides a comprehensive overview of recent advancements in strategies such as genetic engineering, mutagenesis, improving photosynthetic efficiency, nutritional or environmental factors, and cultivation approaches to improve DHA and EPA production efficiency in microalgae cells. Additionally, it explains the application of DHA and EPA-rich microalgae in animal feed, human nutrition- snacks, and supplements to avoid malnutrition and non-communicable diseases.

Improving Meat Quality, Safety and Sustainability in Monogastric Livestock with Algae Feed Additives

Integrating algae (microalgae and seaweeds) into monogastric animal diets presents significant opportunities to improve meat quality, safety, and sustainability. This review synthesizes current knowledge on the nutritional and bioactive compounds found in key microalgae (e.g., Chlorella vulgaris, Spirulina, and Nannochloropsis) and seaweeds (e.g., Ascophyllum nodosum, Ulva), emphasizing their potential benefits for animal health and meat production. Algae-enriched diets substantially increase meat omega-3 fatty acid content and antioxidant capacity, thereby enhancing nutritional value, sensory appeal, and shelf life by mitigating lipid and protein oxidation during storage. Additionally, bioactive compounds in algae demonstrate potent antimicrobial activities capable of reducing pathogenic bacteria such as Salmonella, Escherichia coli, and Campylobacter, significantly contributing to improved meat safety. Environmentally, algae cultivation reduces dependency on arable land and freshwater, promotes nutrient recycling through wastewater use, and substantially decreases greenhouse gas emissions compared to traditional livestock feeds. Nevertheless, challenges persist, including high production costs, scalability concerns, variability in nutrient composition, potential contamination with heavy metals and other toxins, and regulatory constraints. Overcoming these limitations through advancements in cultivation technologies, optimized inclusion strategies, and comprehensive market and regulatory analyses is essential to fully realize the potential of algae in sustainable monogastric livestock feeding systems.

Utilization of Microalgae and Duckweed as Sustainable Protein Sources for Food and Feed: Nutritional Potential and Functional Applications

Aquatic biomass, particularly microalgae and duckweed, presents a promising and sustainable alternative source of plant-based protein and bioactive compounds for food and feed applications. This review highlights the nutritional potential of these aquatic species, focusing on their high protein content, rapid growth rates, and adaptability to nonarable environments. Microalgae, such as Chlorella and Arthrospira spp., and duckweed, such as Lemna minor, are evaluated for their functional food applications, including their roles as protein supplements, bioactive components, antioxidants, and emulsifiers in food formulations. The study also examines their environmental benefits, including wastewater bioremediation, nutrient recycling, and greenhouse gas mitigation, which contribute to a more sustainable agricultural system. Technological advancements in the cultivation, harvesting, and processing of microalgae and duckweed are discussed to enhance their scalability and economic feasibility in food and feed production. The findings suggest that integrating microalgae and duckweed into agricultural and food systems can significantly improve food security, nutritional outcomes, and sustainability. Future research should focus on optimizing cultivation efficiencies, advancing protein extraction techniques, and expanding the applications of aquatic biomass in various food products.

Moving towards novel and sustainable foods: Investigating consumers' intention to consume algae-based foods in a developing country

The world's growing population is putting immense pressure on natural resources and food security. Algae, as a sustainable and nutrient-rich alternative protein source, have gained attention due to their lower environmental impacts and potential health benefits. However, consumer acceptance remains a key challenge, especially in developing countries where awareness is limited. This study investigates the factors influencing Iranian consumers' willingness to consume algae-based foods through the Theory of Planned Behavior (TPB). A survey involving 445 respondents from Mashhad, Iran, was conducted, and the data were analyzed using structural equation modeling. The findings reveal that attitude has the strongest influence on consumption intention, followed by food disgust, subjective norms, knowledge, moral norms, and environmental concerns. Attitude also mediates the relationships between the constructs of disgust, moral norms, knowledge, and environmental concerns with consumption intention. Furthermore, the findings indicate that attitude constitutes the fundamental mechanism of the relationship between knowledge, environmental concerns, and intention. On the other hand, moral norms confirm the existence of a relationship between the subjective norms construct and consumption intention, such that moral norms shape the fundamental mechanism of the relationship between subjective norms and attitude, emphasizing the profound influence of moral values in Iranian consumption culture. In contrast, food neophobia did not have a significant impact on consumption intentions, indicating an openness towards dietary innovations among Iranians. This research contributes to the theoretical advancement in this field by identifying the direct, indirect, and total effects of the extended Theory of Planned Behavior components on the decision to consume algae or algae-containing foods. Practically, the findings from this study can provide guidance for effective introduction and promotion strategies of algae-based food products in emerging markets.

Improvement of growth and lipid accumulation in microalgae with aggregation-induced emission-based nanomaterials towards sustainable lipid production

Microalgae are a hot research area owing to their promising applications for sustainable food, biofunctional compounds, and biofuel feedstock. However, low lipid content in algal biomass is still a challenge that needs to be resolved for commercial use. The current approaches are not satisfactory for achieving high growth and lipid accumulation in algal cells. This research aims to understand and evaluate the effects of light spectral shift on growth and lipid biosynthesis in a green microalga, Chlamydomonas reinhardtii. As a novel approach, an aggregation-induced emission luminogen (AIEgen), TPA-A (C21H19NO), was introduced into the culture media for tailoring the wavelength to a specific range to enhance photosynthesis and lipid production. Algal growth almost doubled at 10 μM TPA-A exposure compared to the control. A significant increase (*p < 0.05) in lipid accumulation was observed in the algal cells exposed to TPA-A. The elevated level of chlorophyll was attributed to fast algal growth. Furthermore, this luminogen was highly biocompatible (∼97% cell viability) on the HaCaT cell line at a concentration of 10 μM in under light conditions. No residues of TPA-A were detected after 7 days in culture media, indicating that this AIEgen was easily degradable. This AIE-based nanomaterial overcomes the conventional fluorophores' aggregation-caused quenching effect by providing increased fluorescence with AIEgen. This approach for lipid induction with increased algal growth provides potential for the algal biofactory to produce sustainable bioproducts and eco-friendly biofuels.

Enhancing Meat Quality and Nutritional Value in Monogastric Livestock Using Sustainable Novel Feed Ingredients

This study explores the potential of novel feed ingredients for monogastric animals, such as pigs and poultry, to enhance meat quality and nutritional value while reducing the environmental footprint of production. Innovative feed options like black soldier fly larvae, Schizochytrium microalga, Laminaria seaweed, fermented soybean hulls, fortified flaxseed and grape pomace have significantly improved meat quality and nutritional traits. Results indicate that these ingredients enrich meat with omega-3 fatty acids, antioxidants, vitamins and minerals, enhancing nutritional value while improving sensory traits such as flavour, tenderness and colour. For instance, including Laminaria seaweed increased iodine content by up to 45%, while Schizochytrium microalga improved omega-3 deposition by over 70%. The inclusion of grape pomace enhanced oxidative stability and extended meat shelf life. This review also discusses the influence of ingredient composition, inclusion levels and processing techniques, alongside challenges such as regulatory constraints, ingredient cost and palatability. The alignment of these alternative feeds with circular economy principles and sustainability goals further emphasizes their role in reducing environmental impact. By summarising recent advancements, this paper underscores the transformative potential of novel feed ingredients in advancing monogastric meat production towards greater nutritional quality, sustainability and consumer acceptance.

Current trends and possibilities of typical microbial protein production approaches: a review

Global population growth and demographic restructuring are driving the food and agriculture sectors to provide greater quantities and varieties of food, of which protein resources are particularly important. Traditional animal-source proteins are becoming increasingly difficult to meet the demand of the current consumer market, and the search for alternative protein sources is urgent. Microbial proteins are biomass obtained from nonpathogenic single-celled organisms, such as bacteria, fungi, and microalgae. They contain large amounts of proteins and essential amino acids as well as a variety of other nutritive substances, which are considered to be promising sustainable alternatives to traditional proteins. In this review, typical approaches to microbial protein synthesis processes were highlighted and the characteristics and applications of different types of microbial proteins were described. Bacteria, fungi, and microalgae can be individually or co-cultured to obtain protein-rich biomass using starch-based raw materials, organic wastes, and one-carbon compounds as fermentation substrates. Microbial proteins have been gradually used in practical applications as foods, nutritional supplements, flavor modifiers, and animal feeds. However, further development and application of microbial proteins require more advanced biotechnological support, screening of good strains, and safety considerations. This review contributes to accelerating the practical application of microbial proteins as a promising alternative protein resource and provides a sustainable solution to the food crisis facing the world.

Microalgal metabolic engineering facilitates precision nutrition and dietary regulation

Microalgae have gained considerable attention as promising candidates for precision nutrition and dietary regulation due to their versatile metabolic capabilities. This review innovatively applies system metabolic engineering to utilize microalgae for precision nutrition and sustainable diets, encompassing the construction of microalgal cell factories, cell cultivation and practical application of microalgae. Manipulating the metabolic pathways and key metabolites of microalgae through multi-omics analysis and employing advanced metabolic engineering strategies, including ZFNs, TALENs, and the CRISPR/Cas system, enhances the production of valuable bioactive compounds, such as omega-3 fatty acids, antioxidants, and essential amino acids. This work begins by providing an overview of the metabolic diversity of microalgae and their ability to thrive in diverse environmental conditions. It then delves into the principles and strategies of metabolic engineering, emphasizing the genetic modifications employed to optimize microalgal strains for enhanced nutritional content. Enhancing PSY, BKT, and CHYB benefits carotenoid synthesis, whereas boosting ACCase, fatty acid desaturases, and elongases promotes polyunsaturated fatty acid production. Here, advancements in synthetic biology, evolutionary biology and machine learning are discussed, offering insights into the precision and efficiency of metabolic pathway manipulation. Also, this review highlights the potential impact of microalgal precision nutrition on human health and aquaculture. The optimized microalgal strains could serve as sustainable and cost-effective sources of nutrition for both human consumption and aquaculture feed, addressing the growing demand for functional foods and environmentally friendly feed alternatives. The tailored microalgal strains are anticipated to play a crucial role in meeting the nutritional needs of diverse populations and contributing to sustainable food production systems.

Industrial Production of Functional Foods for Human Health and Sustainability

Functional foods significantly affect social stability, human health, and food security. Plants and microorganisms are high-quality chassis for the bioactive ingredients in functional foods. Characterised by precise nutrition and the provision of both nutritive and medicinal value, functional foods serve a as key extension of functional agriculture and offer assurance of food availability for future space exploration efforts. This review summarises the main bioactive ingredients in functional foods and their functions, describes the strategies used for the nutritional fortification and industrial production of functional foods, and provides insights into the challenges and future developments in the applications of plants and microorganisms in functional foods. Our review aims to provide a theoretical basis for the development of functional foods, ensure the successful production of new products, and support the U.N. Sustainable Development Goals, including no poverty, zero hunger, and good health and well-being.

Aggregation-Induced Emission Photosensitizer Boosting Algal Growth and Lipid Accumulation

Mass production of microalgae is a research focus owing to their promising aspects for sustainable food, biofunctional compounds, nutraceuticals, and biofuel feedstock. This study uses a novel approach to enhance microalgae-derived biomass and metabolites by using an aggregation-induced emission (AIE) photosensitizer (PS), CN-TPAQ-PF6 ([C32H23N4]+). The unique AIE features of CN-TPAQ-PF6 facilitate nano-aggregation in aquatic media for an effective light spectral shift for photosynthetic augmentation in a green microalga, Chlamydomonas reinhardtii. The high reactive oxygen species (ROS) production capacity and redox-based cellular modulations reveal its potential to upsurge algal growth and lipid biosynthesis and fabricate fatty acid profiles in the metabolic pathways. Algal cells are labeled with other AIE-based nanoprobes, which are suitable as an in vivo visualization toolkit with superior fluorescence. Furthermore, cytotoxicity analysis of CN-TPAQ-PF6 on the HaCat cell line confirms that this AIE PS is biocompatible without adverse impact on living cells. The results demonstrate the property of AIE PS for the first time in enhancing algal growth and lipid accumulation simultaneously.

Monoterpene Hydroxy Lactones Isolated from Thalassiosira sp. Microalga and Their Antibacterial and Antioxidant Activities

Two monoterpenoid lactones, loliolide (1) and epi-loliolide (2), were isolated from the crude dichloromethane extract of a microalga, Thalassiosira sp.). The structures of loliolide (1) and epi-loliolide (2) were elucidated by 1D and 2D NMR analysis, as well as a comparison of their 1H or/and 13C NMR data with those reported in the literature. In the case of loliolide (1), the absolute configurations of its stereogenic carbons were confirmed by X-ray analysis, whereas those of epi-loliolide (2) were determined by NOESY correlations. Loliolide (1) and epi-loliolide (2) were tested for their growth inhibitory activity against two Gram-positive (Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212) and two Gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) bacteria, as well as one clinical isolate (E. coli SA/2, an extended-spectrum β-lactamase producer-ESBL) and two environmental isolates, S. aureus 74/24, a methicillin-resistant (MRSA), and E. faecalis B3/101, a vancomycin-resistant (VRE) isolates. The results showed that none of the tested compounds exhibited antibacterial activity at the highest concentrations tested (325 μM), and both revealed low antioxidant activity, with ORAC values of 2.786 ± 0.070 and 2.520 ± 0.319 µmol TE/100 mg for loliolide (1) and epi-loliolide (2), respectively.

A crosswalk on the genetic and conventional strategies for enhancing astaxanthin production in Haematococcus pluvialis

Astaxanthin is a naturally occurring xanthophyll with powerful: antioxidant, antitumor, and antibacterial properties that are widely employed in food, feed, medicinal and nutraceutical industries. Currently, chemical synthesis dominates the world's astaxanthin market, but the increasing demand for natural products is shifting the market for natural astaxanthin. Haematococcus pluvialis (H. pluvialis) is the factory source of natural astaxanthin when grown in optimal conditions. Currently, various strategies for the production of astaxanthin have been proposed or are being developed in order to meet its market demand. This up-to-date review scrutinized the current approaches or strategies that aim to increase astaxanthin yield from H. pluvialis. We have emphasized the genetic and environmental parameters that increase astaxanthin yield. We also looked at the transcriptomic dynamics caused by environmental factors (phytohormones induction, light, salt, temperature, and nutrient starvation) on astaxanthin synthesizing genes and other metabolic changes. Genetic engineering and culture optimization (environmental factors) are effective approaches to producing more astaxanthin for commercial purposes. Genetic engineering, in particular, is accurate, specific, potent, and safer than conventional random mutagenesis approaches. New technologies, such as CRISPR-Cas9 coupled with omics and emerging computational tools, may be the principal strategies in the future to attain strains that can produce more astaxanthin. This review provides accessible data on the strategies to increase astaxanthin accumulation natively. Also, this review can be a starting point for new scholars interested in H. pluvialis research.

Preventing biofouling in microalgal photobioreactors

Photobioreactors (PBRs) are used to grow the light-requiring microalgae in diverse commercial processes. Often, they are operated as continuous culture over months period. However, with time, biofouling layer develops on the inner surfaces of their walls. The fouling layer formation deteriorates the PBR performance as foulants reduce light penetration in it. Light is essential for photosynthetic cultures, and a deterioration in lighting adversely impacts algae growth and biomass productivity. Fouling requires a frequent shutdown to clean the PBR and add to the environmental impact of the operation by generating many wastewaters contaminated with the cleaning chemicals. Antibiofouling coatings could be used to modify the surfaces of existing and future PBRs. Therefore, transparent and non-toxic fouling-release coatings, produced using hydrogel technology, could transform the existing PBRs into efficient and enduring microalgae culture systems, requiring only the application of the coating to the inner walls, without additional investments in new PBRs.

Sustainable agriculture: leveraging microorganisms for a circular economy

Microorganisms serve as linchpins in agricultural systems. Classic examples include microbial composting for nutrient recovery, using microorganisms in biogas technology for agricultural waste utilization, and employing biofilters to reduce emissions from stables or improve water quality in aquaculture. This mini-review highlights the importance of microbiome analysis in understanding microbial diversity, dynamics, and functions, fostering innovations for a more sustainable agriculture. In this regard, customized microorganisms for soil improvement, replacements for harmful agrochemicals or antibiotics in animal husbandry, and (probiotic) additives in animal nutrition are already in or even beyond the testing phase for a large-scale conventional agriculture. Additionally, as climate change reduces arable land, new strategies based on closed-loop systems and controlled environment agriculture, emphasizing microbial techniques, are being developed for regional food production. These strategies aim to secure the future food supply and pave the way for a sustainable, resilient, and circular agricultural economy. KEY POINTS: • Microbial strategies facilitate the integration of multiple trophic levels, essential for cycling carbon, nitrogen, phosphorus, and micronutrients. • Exploring microorganisms in integrated biological systems is essential for developing practical agricultural solutions. • Technological progress makes sustainable closed-entity re-circulation systems possible, securing resilient future food production.

Foods of the Future: Challenges, Opportunities, Trends, and Expectations

Creating propositions for the near and distant future requires a design to catch the tide of the times and move with or against trends. In addition, appropriate, adaptable, flexible, and transformational projects are needed in light of changes in science, technology, social, economic, political, and demographic fields over time. Humanity is facing a period in which science and developing technologies will be even more important in solving food safety, health, and environmental problems. Adapting to and mitigating climate change; reducing pollution, waste, and biodiversity loss; and feeding a growing global population with safe food are key challenges facing the agri-food industry and the food supply chain, requiring systemic transformation in agricultural systems and sustainable future agri-food. The aim of this review is to compile scientific evidence and data, define, and create strategies for the future in terms of food security, safety, and sufficiency; future sustainable foods and alternative protein sources; factors affecting food and nutrition security and agriculture; and promising food systems such as functional foods, novel foods, synthetic biology, and 3D food printing. In this review, the safety, conservation, nutritional, sensory, welfare, and potential challenges and limitations of food systems and the opportunities to overcome them on the basis of new approaches, innovative interpretations, future possibilities, and technologies are discussed. Additionally, this review also offers suggestions for future research and food trends in light of future perspectives. This article focuses on future sustainable foods, alternative protein sources, and novel efficient food systems, highlights scientific and technological advances and new research directions, and provides a significant perspective on sustainability.

Utilizing Mixed Cultures of Microalgae to Up-Cycle and Remove Nutrients from Dairy Wastewater

This study explores the novel use of mixed cultures of microalgae-Spirulina platensis, Micractinium, and Chlorella-for nutrient removal from dairy wastewater (DW). Microalgae were isolated from a local wastewater treatment plant and cultivated under various light conditions. The results showed significant biomass production, with mixed cultures achieving the highest biomass (2.51 g/L), followed by Spirulina (1.98 g/L) and Chlorella (1.92 g/L). Supplementing DW (75%) with BG medium (25%) significantly enhanced biomass and pH levels, improving pathogenic bacteria removal. Spirulina and mixed cultures exhibited high nitrogen removal efficiencies of 92.56% and 93.34%, respectively, while Chlorella achieved 86.85% nitrogen and 83.45% phosphorus removal. Although growth rates were lower under phosphorus-limited conditions, the microalgae adapted well to real DW, which is essential for effective algal harvesting. Phosphorus removal efficiencies ranged from 69.56% to 86.67%, with mixed cultures achieving the highest removal. Microbial and coliform removal efficiencies reached 97.81%, with elevated pH levels contributing to significant reductions in fecal E. coli and coliform levels. These findings suggest that integrating microalgae cultivation into DW treatment systems can significantly enhance nutrient and pathogen removal, providing a sustainable solution for wastewater management.

Microalgae as future food: Rich nutrients, safety, production costs and environmental effects

The improvement of food security and nutrition has attracted wide attention, and microalgae as the most promising food source are being further explored. This paper comprehensively introduces basic and functional nutrients rich in microalgae by elaborated tables incorporating a wide variety of studies and summarizes factors influencing their accumulation effects. Subsequently, multiple comparisons of nutrients were conducted, indicating that microalgae have a high protein content. Moreover, controllable production costs and environmental friendliness prompt microalgae into the list that contains more promising and reliable future food. However, microalgae and -based foods approved and sold are limited strictly, showing that safety is a key factor affecting dietary consideration. Notably, sensory profiles and ingredient clarity play an important role in improving the acceptance of microalgae-based foods. Finally, based on the bottleneck in the microalgae food industry, suggestions for its future development were discussed.

What are the growth kinetics and biochemical compositions of microalgae isolated from diverse aquatic ecosystems in Morocco, France, and Tunisia?

Thirty-six microalgae belonging to five taxonomic groups (Cyanobacteria, Chlorophyceae, Diatomophyceae, Euglenophyceae, and Eustigmatophyceae) were identified from six freshwater ecosystems in Morocco, two treatment stations in Etueffont landfill in France and three hot spring waters in Tunisia. Investigations on species growth kinetics and growth rates showed that the cyanobacterium Leptolyngbya gelatinosa exhibited both the highest biomass and growth rate with 4 g DW L-1 and 0.282 day-1, respectively. A significant protein production (more than 40% DW) was observed across the studied species. Cyanobacteria and chlorophytes stood out for their increased protein production with a maximum (66.63 ± 3.84% DW) attained by the cyanobacterium Leptolyngbya sp. Chlorophytes produced substantial amounts of carbohydrates (more than 20% DW). Euglenophytes including Phacus orbicularis and Euglena ehrenbergii along with the chlorophyte Graesiella sp. accumulated significant amounts of lipids (up to 31.12% DW).

Perspectives on cultivation and harvesting technologies of microalgae, towards environmental sustainability and life cycle analysis

The development of algae is seen as a potential and ecologically sound approach to address the increasing demands in multiple sectors. However, successful implementation of processes is highly dependent on effective growing and harvesting methods. The present study provides a complete examination of contemporary techniques employed in the production and harvesting of algae, with a particular emphasis on their sustainability. The review begins by examining several culture strategies, encompassing open ponds, closed photobioreactors, and raceway ponds. The analysis of each method is conducted in a systematic manner, with a particular focus on highlighting their advantages, limitations, and potential for expansion. This approach ensures that the conversation is in line with the objectives of sustainability. Moreover, this study explores essential elements of algae harvesting, including the processes of cell separation, dewatering, and biomass extraction. Traditional methods such as centrifugation, filtration, and sedimentation are examined in conjunction with novel, environmentally concerned strategies including flocculation, electro-coagulation, and membrane filtration. It evaluates the impacts on the environment that are caused by the cultivation process, including the usage of water and land, the use of energy, the production of carbon dioxide, and the runoff of nutrients. Furthermore, this study presents a thorough examination of the current body of research pertaining to Life Cycle Analysis (LCA) studies, presenting a perspective that emphasizes sustainability in the context of algae harvesting systems. In conclusion, the analysis ends up with an examination ahead at potential areas for future study in the cultivation and harvesting of algae. This review is an essential guide for scientists, policymakers, and industry experts associated with the advancement and implementation of algae-based technologies.

Beauvericin and enniatin B mycotoxins alter aquatic ecosystems: Effects on green algae

Myxotoxins can contaminate algal-based products and arrive to the food chain to consumers producing chronic toxicity effects. Here, we studied phytotoxicity of mycotoxins, beauvericin (BEA) and ennaitin B (ENN B) in four phytoplankton strains: Acutodesmus sp., Chlamydomonas reinhardtii, Haematococcus pluvialis, and Monoraphidium griffithii, which are all green algae. It was tested the capacity of clearing the media of BEA and ENN B at different concentrations by comparing nominal and measured quantifications. Results revealed that Acutodesmus sp. and C. reinhardtii tended to flow up and down growth rate without reaching values below 50% or 60%, respectively. On the other hand, for H. pluvialis and M. griffith, IC50 values were reached. Regarding the clearance of media, in individual treatment a decrease of the quantified mycotoxin between nominal and measured values was observed; while in binary treatment, differences among both values were higher and more noted for BEA than for ENN B.

Exploring the dynamics of algae-associated microbiome during the scale-up process of Tetraselmis sp. microalgae: A metagenomics approach

Microalgae have become a key source of valuable compounds, promoting commercial scale applications. However, biological contamination is one of the most critical problems associated with large scale algal production, especially in open systems such as raceway ponds. The current research is the first to assess the effectiveness of open raceway ponds in maintaining a pure culture of Tetraselmis sp., starting from 20 L culture up to 10,000 L culture. Microbial profiling of each successive stage revealed lower abundance of eukaryotic organisms, whereas bacterial abundance increased notably resulting in a significant decrease in Tetraselmis sp. abundance. Furthermore, several bacteria with algae growth-promoting properties were found throughout the various culture stages including Balneola, Roseovarius, and Marinobacter. However, some algae-suppressive bacteria were evidenced at later stages such as Ulvibacter, Aestuariicoccus, and Defluviimonas. Overall, due to the increasing bacterial concentration, considerations limiting bacterial contamination need to be taken.

Transparent antibiofouling coating to improve the efficiency of Nannochloropsis gaditana and Chlorella sorokiniana culture photobioreactors at the pilot-plant scale

The implementation of industrial-scale facilities for microalgae cultivation is limited due to the high operation costs. One of the main problems in obtaining an efficient and long-lasting microalgae culture system is biofouling. The particular issue when developing antibiofouling surfaces for microalgae cultures is that the material must be transparent. The main purpose of this work was to evaluate the antibiofouling efficiency of a non-toxic polydimethylsiloxane-based coating prepared with polyethylene glycol-based copolymer on different photobioreactors at the pilot-plant scale. The antifouling properties result from the development of a fouling-release coating utilizing hydrogel technology. Nannochloropsis gaditana and Chlorella sorokiniana were cultured outdoors for 3 months over the summer, when biofouling formation is at its highest due to environmental conditions, to test the coating's antibiofouling efficiency. Although biofouling was not completely prevented in either photobioreactor, the coating significantly reduced cell adhesion compared to the polydimethylsiloxane control (70% less adhesion). Therefore, this coating was shown to be a good alternative for constructing efficient closed-photobioreactors at the pilot-plant scale, at least for cultures lasting 3 months.

Spirulina platensis ameliorates hepatic oxidative stress and DNA damage induced by aflatoxin B1 in rats

Aflatoxin B1 (AFB1) is a widely distributed mycotoxin, causing hepatotoxicity and oxidative stress. One of the most famous unicellular cyanobacteria is Spirulina platensis (SP) which is well known for its antioxidant characteristics against many toxicants. Therefore, this study aimed to investigate the antioxidant potential and hepatoprotective ability of SP against oxidative stress and cytotoxicity in male Wistar albino rats intraperitoneally injected with AFB1. Rats were separated into five groups as follows: negative control administered with saline; SP (1000 mg/kg BW) for two weeks; AFB1 (2.5 mg/kg BW) twice on days 12 and 14; AFB1 (twice) + 500 mg SP/kg BW (for two weeks) and AFB1 (twice) + 1000 mg SP/kg BW (for two weeks). Liver and blood samples were assembled for histological and biochemical analyses. AFB1 intoxicated rats showed a marked elevation in serum biochemical parameters (ALP, ALT, and AST), hepatic lipid peroxidation (MDA and NO), and proliferating cell nuclear antigen (PCNA) indicating DNA damage. Moreover, AFB1 caused suppression of antioxidant biomarkers (SOD, GHS, GSH-Px, and CAT). However, the elevated serum levels of biochemical parameters and PCNA expression were reduced by SP. Moreover, SP lowered oxidative stress and lipid peroxidation markers in a dose-dependent manner. To sum up, SP supplementation is capable of decreasing AFB1 toxicity through its powerful antioxidant activity.

Algae-based approaches for Holistic wastewater management: A low-cost paradigm

Aquatic algal communities demonstrated their appeal for diverse industrial applications due to their vast availability, ease of harvest, lower production costs, and ability to biosynthesize valuable molecules. Algal biomass is promising because it can multiply in water and on land. Integrated algal systems have a significant advantage in wastewater treatment due to their ability to use phosphorus and nitrogen, simultaneously accumulating heavy metals and toxic substances. Several species of microalgae have adapted to thrive in these harsh environmental circumstances. The potential of algal communities contributes to achieving the United Nations' sustainable development goals in improving aquaculture, combating climate change, reducing carbon dioxide (CO2) emissions, and providing biomass as a biofuel feedstock. Algal-based biomass processing technology facilitates the development of a circular bio-economy that is both commercially and ecologically viable. An integrated bio-refinery process featuring zero waste discharge could be a sustainable solution. In the current review, we will highlight wastewater management by algal species. In addition, designing and optimizing algal bioreactors for wastewater treatment have also been incorporated.

Biotreatment of Industrial Wastewater using Microalgae: A Tool for a Sustainable Bioeconomy

Fresh water is one of the essential sources of life, and its requirement has increased in the past years due to population growth and industrialization. Industries use huge quantities of fresh water for their processes, and generate high quantities of wastewater rich in organic matter, nitrates, and phosphates. These effluents have contaminated the freshwater sources and there is a need to recycle this wastewater in an ecologically harmless manner. Microalgae use the nutrients in the wastewater as a medium for growth and the biomass produced are rich in nutrition that can cater growing food and energy needs. The primary and secondary metabolites of microalgae are utilized as biofuel and as active ingredients in cosmetics, animal feed, therapeutics, and pharmaceutical products. In this review, we explore food processing industries like dairy, meat, aquaculture, breweries, and their wastewater for the microalgal growth. Current treatment methods are expensive and energy demanding, which indirectly leads to higher greenhouse gas emissions. Microalgae acts as a potential biotreatment tool and mitigates carbon dioxide due to their high photosynthetic efficiency. This review aims to address the need to recycle wastewater generated from such industries and potentiality to use microalgae for biotreatment. This will help to build a circular bioeconomy by using wastewater as a valuable resource to produce valuable products.

Unlocking microalgal host-exploring dark-growing microalgae transformation for sustainable high-value phytochemical production

Microalgae have emerged as a promising, next-generation sustainable resource with versatile applications, particularly as expression platforms and green cell factories. They possess the ability to overcome the limitations of terrestrial plants, such non-arable land, water scarcity, time-intensive growth, and seasonal changes. However, the heterologous expression of interested genes in microalgae under heterotrophic cultivation (dark mode) remains a niche area within the field of engineering technologies. In this study, the green microalga, Chlorella sorokiniana AARL G015 was chosen as a potential candidate due to its remarkable capacity for rapid growth in complete darkness, its ability to utilize diverse carbon sources, and its potential for wastewater treatment in a circular bioeconomy model. The aims of this study were to advance microalgal genetic engineering via dark cultivation, thereby positioning the strain as promising dark-host for expressing heterologous genes to produce high-value phytochemicals and ingredients for food and feed. To facilitate comprehensive screening based on resistance, eleven common antibiotics were tested under heterotrophic condition. As the most effective selectable markers for this strain, G418, hygromycin, and streptomycin exhibited growth inhibition rates of 98%, 93%, and 92%, respectively, ensuring robust long-term transgenic growth. Successful transformation was achieved through microalgal cell cocultivation with Agrobacterium under complete darkness verified through the expression of green fluorescence protein and β-glucuronidase. In summary, this study pioneers an alternative dark-host microalgal platform, using, Chlorella, under dark mode, presenting an easy protocol for heterologous gene transformation for microalgal host, devoid of the need for expensive equipment and light for industrial production. Furthermore, the developed genetic transformation methodology presents a sustainable way for production of high-value nutrients, dietary supplements, nutraceuticals, proteins and pharmaceuticals using heterotrophic microalgae as an innovative host system.

The Effect of Lactiplantibacillus plantarum I-Enriched Diet on the Phenolic Content and Antioxidant Capacity of Queen Scallop (Aequipecten opercularis Linnaeus, 1758) Extracts

The use of probiotics in the diet of bivalves poses a great potential in aquaculture as an alternative to antibiotics. The aim of this study was to assess the effect of Lactiplantibacillus plantarum I on the phenolic content and antioxidant capacity (AC) of queen scallop extracts after one month of feeding. Total phenols (TP) ranged from 28.17 ± 3.11 to 58.58 ± 8.57 mg GAE/100 g, total non-flavonoids (TNF) from 23.33 ± 3.66 to 36.56 ± 9.91 mg GAE/100 g, and total flavonoids (TF) from 10.56 ± 5.57 to 30.16 ± 1.69 mg CE/100 g. AC was assessed via three different methods: the ferric-reducing ability of plasma assay (FRAP), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic) acid assay (ABTS), and 2,2-diphenyl-1-picryhydrazyl assay (DPPH). FRAP values ranged from 0.13 ± 0.03 to 0.17 ± 0.02 µM AA/g, ABTS from 0.68 ± 0.11 to 2.79 ± 0.34 µM AA/g, and DPPH from 1.75 ± 0.17 to 2.98 ± 0.53 µM AA/g. Among all extracts, the best phenolic content and AC were observed in water extracts from queen scallops. The bivalves treated with the Lactiplantibacillus plantarum I-enriched diet showed higher AC according to the FRAP assay in all extracts. A significant correlation was observed between AC and TP and TNF in control and Lactiplantibacillus plantarum I-treated scallops.

Investigating the Potential Anti-Alzheimer's Disease Mechanism of Marine Polyphenols: Insights from Network Pharmacology and Molecular Docking

Marine polyphenols, including eckol(EK), dieckol(DK), and 8,8'-bieckol(BK), have attracted attention as bioactive ingredients for preventing Alzheimer's disease (AD). Since AD is a multifactorial disorder, the present study aims to provide an unbiased elucidation of unexplored targets of AD mechanisms and a systematic prediction of effective preventive combinations of marine polyphenols. Based on the omics data between each compound and AD, a protein-protein interaction (PPI) network was constructed to predict potential hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to provide further biological insights. In the PPI network of the top 10 hub genes, AKT1, SRC, EGFR, and ESR1 were common targets of EK and BK, whereas PTGS2 was a common target of DK and BK. GO and KEGG pathway analysis revealed that the overlapped genes between each compound and AD were mainly enriched in EGFR tyrosine kinase inhibitor resistance, the MAPK pathway, and the Rap1 and Ras pathways. Finally, docking validation showed stable binding between marine polyphenols and their top hub gene via the lowest binding energy and multiple interactions. The results expanded potential mechanisms and novel targets for AD, and also provided a system-level insight into the molecular targets of marine polyphenols against AD.

Microalgae-based domestic wastewater treatment: a review of biological aspects, bioremediation potential, and biomass production with biotechnological high-value

This review aims to perform an updated bibliographical survey on the cultivation of microalgae in domestic wastewater with a focus on biotechnological aspects. It was verified that the largest number of researches developed was about cultures in microalgae-bacteria consortium and mixed cultures of microalgae, followed by researches referring to the species Chlorella vulgaris and to the family Scenedesmaceae. According to published studies, these microorganisms are efficient in the biological treatment of domestic wastewater, as well as in the production of high value-added biomass, as they are capable of biosorbing the organic and inorganic compounds present in the culture medium, thus generating cells with high levels of lipids, proteins, and carbohydrates. These compounds are of great importance for different industry sectors, such as pharmaceuticals, food, and also for agriculture and aquaculture. In addition, biomolecules produced by microalgae can be extracted for several biotechnological applications; however, most studies focus on the production of biofuels, with biodiesel being the main one. There are also other emerging applications that still require more in-depth research, such as the use of biomass as a biofertilizer and biostimulant in the production of bioplastic. Therefore, it is concluded that the cultivation of microalgae in domestic wastewater is a sustainable way to promote effluent bioremediation and produce valuable biomass for the biobased industry, contributing to the development of technology for the green economy.

Applications of Microalgae in Foods, Pharma and Feeds and Their Use as Fertilizers and Biostimulants: Legislation and Regulatory Aspects for Consideration

Microalgae are a rich resource of lipids, proteins, carbohydrates and pigments with nutritional and health benefits. They increasingly find use as ingredients in functional foods and feeds as well as in cosmetics and agricultural products including biostimulants. One of their distinct advantages is their ability to grow on wastewaters and other waste streams, and they are considered an environmentally friendly and cheap method to recover nutrients and remove pollutants from the environment. However, there are limits concerning their applications if grown on certain waste streams. Within, we collate an overview of existing algal applications and current market scenarios for microalgal products as foods and feeds along with relevant legislative requirements concerning their use in Europe and the United States. Microalgal compounds of interest and their extraction and processing methodologies are summarized, and the benefits and caveats of microalgae cultivated in various waste streams and their applications are discussed.

Astaxanthin: Past, Present, and Future

Astaxanthin (AX), a lipid-soluble pigment belonging to the xanthophyll carotenoids family, has recently garnered significant attention due to its unique physical properties, biochemical attributes, and physiological effects. Originally recognized primarily for its role in imparting the characteristic red-pink color to various organisms, AX is currently experiencing a surge in interest and research. The growing body of literature in this field predominantly focuses on AXs distinctive bioactivities and properties. However, the potential of algae-derived AX as a solution to various global environmental and societal challenges that threaten life on our planet has not received extensive attention. Furthermore, the historical context and the role of AX in nature, as well as its significance in diverse cultures and traditional health practices, have not been comprehensively explored in previous works. This review article embarks on a comprehensive journey through the history leading up to the present, offering insights into the discovery of AX, its chemical and physical attributes, distribution in organisms, and biosynthesis. Additionally, it delves into the intricate realm of health benefits, biofunctional characteristics, and the current market status of AX. By encompassing these multifaceted aspects, this review aims to provide readers with a more profound understanding and a robust foundation for future scientific endeavors directed at addressing societal needs for sustainable nutritional and medicinal solutions. An updated summary of AXs health benefits, its present market status, and potential future applications are also included for a well-rounded perspective.

Intestinal Immune Cell Populations, Barrier Function, and Microbiomes in Broilers Fed a Diet Supplemented with Chlorella vulgaris

This study aimed to evaluate the effects of dietary Chlorella vulgaris (CV) on the distribution of immune cells, intestinal morphology, intestinal barrier function, antioxidant markers, and the cecal microbiome in 10-day-old broiler chickens. A total of 120 day-old Ross 308 male broiler chicks were assigned to two dietary treatments using a randomized complete block design, with body weight as the blocking factor. Birds fed a diet containing CV showed an increase in CD4⁺ T cells (p < 0.05) compared to those fed the control diet. The relative mRNA expression of intestinal epithelial barrier function-related markers (occludin and avian β-defensin 5) was elevated (p < 0.05) in the CV-supplemented group compared to the control group. The alpha diversity indices (Chao1 and observed features) of the cecal microbiome in 10-day-old birds increased (p < 0.05), indicating higher richness within the cecal bacterial community. In the microbiome analysis, enriched genera abundance of Clostridium ASF356 and Coriobacteriaceae CHKCI002 was observed in birds fed the diet containing CV compared to those fed the control diet. Taken together, dietary CV supplementation might alter intestinal barrier function, immunity, and microbiomes in 10-day-old broiler chickens.

Algal nutraceuticals: A perspective on metabolic diversity, current food applications, and prospects in the field of metabolomics

The current consumers' demand for food naturalness is urging the search for new functional foods of natural origin with enhanced health-promoting properties. In this sense, algae constitute an underexplored biological source of nutraceuticals that can be used to fortify food products. Both marine macroalgae (or seaweeds) and microalgae exhibit a myriad of chemical constituents with associated features as a result of their primary and secondary metabolism. Thus, primary metabolites, especially polysaccharides and phycobiliproteins, present interesting properties to improve the rheological and nutritional properties of food matrices, whereas secondary metabolites, such as polyphenols and xanthophylls, may provide interesting bioactivities, including antioxidant or cytotoxic effects. Due to the interest in algae as a source of nutraceuticals by the food and related industries, novel strategies should be undertaken to add value to their derived functional components. As a result, metabolomics is considered a high throughput technology to get insight into the full metabolic profile of biological samples, and it opens a wide perspective in the study of algae metabolism, whose knowledge is still little explored. This review focuses on algae metabolism and its applications in the food industry, paying attention to the promising metabolomic approaches to be developed aiming at the functional characterization of these organisms.

Edible microalgae: potential candidate for developing edible vaccines

Infectious diseases are always a threat to all living beings. Today, in this world pathogens have no difficulty reaching anywhere. Every year new and deadly diseases are born and most of them are caused by viruses. Vaccines can provide lifelong immunity against infectious diseases, but the production cost of vaccines is unaffordable for a layman and traditional vaccines have certain limitations with storage and delivery. However, edible vaccines have shifted this paradigm and have received acceptance all over the world, especially in developing countries. Microalgae are one of the potential candidates for developing edible vaccines. Modifying microalgae as edible vaccines are gaining worldwide attention, especially in the world of science. Microalgae can augment the immune system as they are a promising source for antigen carriers and many of them are regarded as safe to eat. Moreover, they are a pantry of proteins, vitamins, minerals, and other secondary metabolites like alkaloids, phenols, and terpenes. In addition, being resistant to animal pathogens they are less sophisticated for genetic modification. This review analyses the potential scope of microalgae as an edible vaccine source.

Biomass, photosynthetic activity, and biomolecule composition in Chlorella fusca (Chlorophyta) cultured in a raceway pond operated under greenhouse conditions

Raceways are widely used as microalgae culture systems due to their low cost, but they are not the best option for biomass yield. Understanding in situ photosynthetic performance can be a first step to increase their biomass productivity. This study aimed at comparing the real time photosynthetic activity in a greenhouse raceway culture (250L) with discrete measurements under laboratory conditions. We evaluated the photophysiology and biochemical composition of Chlorella fusca culture up to 120h. In situ photosynthetic activity was continuously monitored and compared to discrete ex situ measurements; biochemical compounds were measured daily. The results showed a final biomass density of 0.45gL^-1 (5 days - 120h) and an increase of the electron transport rate (ETR) up to 48h but decreased thereafter. When the relative ETR was estimated considering the absorption coefficient (a) positive correlations of this parameter with photosynthetic capacity, cell density, biomass, biocompounds and antioxidant activity were obtained, whereas no correlation was detected without considering a. In situ photosynthesis monitoring showed higher absolute maximal ETR (10 - 160 μmol m^-3s^-1) than discrete ex situ measurements. We demonstrated the importance of considering the light absorption coefficient for expressing photosynthetic capacity and showed that C. fusca can produce, in the short-term, bioactive compounds that are correlated to photosynthetic conditions.

Microbial meat: A sustainable vegan protein source produced from agri-waste to feed the world

In the modern world, animal and plant protein may not meet the sustainability criteria due to their high need for arable land and potable water consumption, among other practices. Considering the growing population and food shortage, finding alternative protein sources for human consumption is an urgent issue that needs to be solved, especially in developing countries. In this context, microbial bioconversion of valuable materials in nutritious microbial cells represent a sustainable alternative to the food chain. Microbial protein, also known as single-cell protein (SCP), consist of algae biomass, fungi or bacteria that are currently used as food source for both humans and animals. Besides contributing as a sustainable source of protein to feed the world, producing SCP, is important to reduce waste disposal problems and production costs meeting the sustainable development goals. However, for microbial protein as feed or food to become an important and sustainable alternative, addressing the challenges of raising awareness and achieving wider public regulatory acceptance is real and must be addressed with care and convenience. In this work, we critically reviewed the potential technologies for microbial protein production, its benefits, safety, and limitations associated with its uses, and perspectives for broader large-scale implementation. We argue that the information documented in this manuscript will assist in developing microbial meat as a major protein source for the vegan world.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

Graphical abstract

An extensive review of marine pigments: sources, biotechnological applications, and sustainability

The global demand for food and healthcare products based on natural compounds means that the industrial and scientific sectors are on a continuous search for natural colored compounds that can contribute to the replacement of synthetic colors. Natural pigments are a heterogeneous group of chemical molecules, widely distributed in nature. Recently, the interest in marine organisms has increased as they represent the most varied environment in the world and provide a wide range of colored compounds with bioactive properties and biotechnological applications in areas such as the food, pharmaceutical, cosmetic, and textile industries. The use of marine-derived pigments has increased during the last two decades because they are environmentally safe and healthy compounds. This article provides a comprehensive review of the current knowledge of sources, applications, and sustainability of the most important marine pigments. In addition, alternatives to protect these compounds from environmental conditions and their applications in the industrial sector are reviewed.

Functional properties of bioactive compounds from Spirulina spp.: Current status and future trends

•

Functional foods that contain bioactive compounds (BC) and provide health benefits;

•

Spirulina is a cyanobacterium considered blue microalgae rich in BC;

•

BC from Spirulina have interesting health effects;

•

Chlorophyll, carotenoids, and phycocyanin are natural corants from Spirulina;

•

Spirulina has potential as an ingredient for application in functional foods.

Functional foods show non-toxic bioactive compounds that offer health benefits beyond their nutritional value and beneficially modulate one or more target functions in the body. In recent decades, there has been an increase in the trend toward consuming foods rich in bioactive compounds, less industrialized, and with functional properties. Spirulina, a cyanobacterium considered blue microalgae, widely found in South America, stands out for its rich composition of bioactive compounds, as well as unsaturated fatty acids and essential amino acids, which contribute to basic human nutrition and can be used as a protein source for diets free from animal products. In addition, they have colored compounds, such as chlorophylls, carotenoids, phycocyanins, and phenolic compounds which can be used as corants and natural antioxidants. In this context, this review article presents the main biological activities of spirulina as an anticancer, neuroprotective, probiotic, anti-inflammatory, and immune system stimulating effect. Furthermore, an overview of the composition of spirulina, its potential for different applications in functional foods, and its emerging technologies are covered in this review.

Regulation of Cholesterol Metabolism by Phytochemicals Derived from Algae and Edible Mushrooms in Non-Alcoholic Fatty Liver Disease

Cholesterol synthesis occurs in almost all cells, but mainly in hepatocytes in the liver. Cholesterol is garnering increasing attention for its central role in various metabolic diseases. In addition, cholesterol is one of the most essential elements for cells as both a structural source and a player participating in various metabolic pathways. Accurate regulation of cholesterol is necessary for the proper metabolism of fats in the body. Disturbances in cholesterol homeostasis have been linked to various metabolic diseases, such as hyperlipidemia and non-alcoholic fatty liver disease (NAFLD). For many years, the use of synthetic chemical drugs has been effective against many health conditions. Furthermore, from ancient to modern times, various plant-based drugs have been considered local medicines, playing important roles in human health. Phytochemicals are bioactive natural compounds that are derived from medicinal plants, fruit, vegetables, roots, leaves, and flowers and are used to treat a variety of diseases. They include flavonoids, carotenoids, polyphenols, polysaccharides, vitamins, and more. Many of these compounds have been proven to have antioxidant, anti-inflammatory, antiobesity and antihypercholesteremic activity. The multifaceted role of phytochemicals may provide health benefits to humans with regard to the treatment and control of cholesterol metabolism and the diseases associated with this disorder, such as NAFLD. In recent years, global environmental climate change, the COVID-19 pandemic, the current war in Europe, and other conflicts have threatened food security and human nutrition worldwide. This further emphasizes the urgent need for sustainable sources of functional phytochemicals to be included in the food industry and dietary habits. This review summarizes the latest findings on selected phytochemicals from sustainable sources-algae and edible mushrooms-that affect the synthesis and metabolism of cholesterol and improve or prevent NAFLD.

Cultivation of microalgae on food waste: Recent advances and way forward

Microalgae are photosynthetic microbes that can synthesize compounds of therapeutic potential with wide applications in the food, bioprocessing and pharmaceutical sector. Recent research advances have therefore, focused on finding suitable economic substrates for the sustainable cultivation of microalgae. Among such substrates, food derived waste specifically from the starch, meat, dairy, brewery, oil and fruit and vegetable processing industries has gained popularity but poses numerous challenges. Pretreatment, dilution of waste water supernatants, mixing of different food waste streams, utilizing two-stage cultivation and other biorefinery approaches have been intensively explored for multifold improvement in microalgal biomass recovery from food waste. This review discusses the advances and challenges associated with cultivation of microalgae on food waste. The review suggests that there is a need to standardize different waste substrates in terms of general composition, genetically engineered microalgal strains, tackling process scalability issues, controlling wastewater toxicity and establishing a waste transportation chain.

Microalgae biomass concentration and reuse of water as new cultivation medium using ceramic membrane filtration

The aim of this study is to advance means for microalgae dewatering with the simultaneous reuse of water as new cultivation medium, specifically through ceramic membrane filtration. Three algae, namely, Spirulina platensis, Scenedesmus obliquus, and Chlorella sorokiniana were tested by filtering suspensions with four ceramic membranes having nominal pore sizes of 0.8 μm, 0.14 μm, 300 kDa, 15 kDa. The observed flux values and organic matter removal rates were related to the membrane pore size and cake layer properties, with some differences in productivity between algae types, likely due to cell size and shape. Interestingly, similar near steady-state fluxes (70-120 L m^-2h^-1) were measured using membranes with nominal pore size above 15 kDa, suggesting the dominance of cake layer filtration independently of the initial flux. Virtually complete algae cells rejections and high nutrient passage (>75%) were observed in all combinations. When the permeate streams were used as media for new growth cycles of the various algae, no or little growth was observed with Spirulina p., while Chlorella s. (permeate from 300 kDa membrane) and especially Scenedesmus o. (permeate from 0.14 μm membrane) showed the fastest growth rates, almost comparable to those observed with ideal fresh media.