Generation of microalga Chlamydomonas reinhardtii expressing shrimp antiviral dsRNA without supplementation of antibiotics

Structural modelling and preventive strategy targeting of WSSV hub proteins to combat viral infection in shrimp Penaeus monodon

White spot syndrome virus (WSSV) presents a considerable peril to the aquaculture sector, leading to notable financial consequences on a global scale. Previous studies have identified hub proteins, including WSSV051 and WSSV517, as essential binding elements in the protein interaction network of WSSV. This work further investigates the functional structures and potential applications of WSSV hub complexes in managing WSSV infection. Using computational methodologies, we have successfully generated comprehensive three-dimensional (3D) representations of hub proteins along with their three mutual binding counterparts, elucidating crucial interaction locations. The results of our study indicate that the WSSV051 hub protein demonstrates higher binding energy than WSSV517. Moreover, a unique motif, denoted as "S-S-x(5)-S-x(2)-P," was discovered among the binding proteins. This pattern perhaps contributes to the detection of partners by the hub proteins of WSSV. An antiviral strategy targeting WSSV hub proteins was demonstrated through the oral administration of dual hub double-stranded RNAs to the black tiger shrimp, Penaeus monodon, followed by a challenge assay. The findings demonstrate a decrease in shrimp mortality and a cessation of WSSV multiplication. In conclusion, our research unveils the structural features and dynamic interactions of hub complexes, shedding light on their significance in the WSSV protein network. This highlights the potential of hub protein-based interventions to mitigate the impact of WSSV infection in aquaculture.

Harnessing the potential of microalgae for the production of monoclonal antibodies and other recombinant proteins

Monoclonal antibodies (mAbs) have become indispensable tools in various fields, from research to therapeutics, diagnostics, and industries. However, their production, primarily in mammalian cell culture systems, is cost-intensive and resource-demanding. Microalgae, diverse photosynthetic microorganisms, are gaining attention as a favorable option for manufacturing mAbs and various other recombinant proteins. This review explores the potential of microalgae as a robust expression system for biomanufacturing high-value proteins. It also highlights the diversity of microalgae species suitable for recombinant protein. Nuclear and chloroplast genomes of some microalgae have been engineered to express mAbs and other valuable proteins. Codon optimization, vector construction, and other genetic engineering techniques have significantly improved recombinant protein expression in microalgae. These accomplishments demonstrate the potential of microalgae for biopharmaceutical manufacturing. Microalgal biotechnology holds promise for revolutionizing the production of mAbs and other therapeutic proteins, offering a sustainable and cost-effective solution to address critical healthcare needs.

The synthetic future of algal genomes

Algae are diverse organisms with significant biotechnological potential for resource circularity. Taking inspiration from fermentative microbes, engineering algal genomes holds promise to broadly expand their application ranges. Advances in genome sequencing with improvements in DNA synthesis and delivery techniques are enabling customized molecular tool development to confer advanced traits to algae. Efforts to redesign and rebuild entire genomes to create fit-for-purpose organisms currently being explored in heterotrophic prokaryotes and eukaryotic microbes could also be applied to photosynthetic algae. Future algal genome engineering will enhance yields of native products and permit the expression of complex biochemical pathways to produce novel metabolites from sustainable inputs. We present a historical perspective on advances in engineering algae, discuss the requisite genetic traits to enable algal genome optimization, take inspiration from whole-genome engineering efforts in other microbes for algal systems, and present candidate algal species in the context of these engineering goals.

Smart nano generation of transgenic algae expressing white spot syndrome virus in shrimps for inner ear-oral infection treatments using the spotted hyena optimizer (SHO)-Long short-term memory algorithm

Nanotechnology offers a promising avenue to amplify the effectiveness and precision of using transgenic algae in managing WSSV in shrimp by possibly crafting nano-carriers for targeted therapeutic agent delivery or modifying algae cells at a molecular level. Leveraging the capabilities of nano-scale interventions, this study could explore innovative means to manipulate cellular processes, control biological interactions, and enhance treatment efficacy while minimizing undesirable impacts in aquatic environments. The White Spot Syndrome Virus (WSSV) is a double-stranded DNA virus with a tail and rod form that belongs to theNimaviridaefamily. There is no workable way to manage this illness at the moment. This research proposes a new model based on the Long Short-Term Memory (LSTM) and Spotted Hyena Optimizer (SHO) method to control the inner ear-oral infection, utilizing transgenic algae (Chlamydomonas reinhardtii). It is pretty tricky to modify the weight matrix in LSTM. The output will be more accurate if the weight of the neurons is exact. Histological examinations and nested polymerase chain reaction (PCR) testing were performed on the challenged shrimp every 4 h to assess the degree of white spot disease. The SHO-LSTM has shown the highest accuracy and Roc value (98.12% and 0.93, respectively) and the lowest error values (MSE = 0.182 and MAE = 0.48). The hybrid optimized model improves the overall inner ear-oral linked neurological diseases detection ratio. Additionally, with the slightest technical complexity, it effectively controls the forecast factors required to anticipate the ENT. Algal cells were found to be particularly well-suited for inner ear-oral infections, and shrimps fed a transgenic line had the best survival ratio in WSSV infection studies, with 87% of the shrimp surviving. This shows that using this line would effectively stop the spread of WSSV in shrimp populations.

RNAi-Based Therapy: Combating Shrimp Viral Diseases

Shrimp aquaculture has become a vital industry, meeting the growing global demand for seafood. Shrimp viral diseases have posed significant challenges to the aquaculture industry, causing major economic losses worldwide. Conventional treatment methods have proven to be ineffective in controlling these diseases. However, recent advances in RNA interference (RNAi) technology have opened new possibilities for combating shrimp viral diseases. This cutting-edge technology uses cellular machinery to silence specific viral genes, preventing viral replication and spread. Numerous studies have shown the effectiveness of RNAi-based therapies in various model organisms, paving the way for their use in shrimp health. By precisely targeting viral pathogens, RNAi has the potential to provide a sustainable and environmentally friendly solution to combat viral diseases in shrimp aquaculture. This review paper provides an overview of RNAi-based therapy and its potential as a game-changer for shrimp viral diseases. We discuss the principles of RNAi, its application in combating viral infections, and the current progress made in RNAi-based therapy for shrimp viral diseases. We also address the challenges and prospects of this innovative approach.

Accelerating Chloroplast Engineering: A New System for Rapid Generation of Marker-Free Transplastomic Lines of Chlamydomonas reinhardtii

'Marker-free' strategies for creating transgenic microorganisms avoid the issue of potential transmission of antibiotic resistance genes to other microorganisms. An already-established strategy for engineering the chloroplast genome (=plastome) of the green microalga Chlamydomonas reinhardtii involves the restoration of photosynthetic function using a recipient strain carrying a plastome mutation in a key photosynthesis gene. Selection for transformant colonies is carried out on minimal media, such that only those cells in which the mutated gene has been replaced with a wild-type copy carried on the transgenic DNA are capable of phototrophic growth. However, this approach can suffer from issues of efficiency due to the slow growth of C. reinhardtii on minimal media and the slow die-back of the untransformed lawn of cells when using mutant strains with a limited photosensitivity phenotype. Furthermore, such phototrophic rescue has tended to rely on existing mutants that are not necessarily ideal for transformation and targeted transgene insertion: Mutants carrying point mutations can easily revert, and those with deletions that do not extend to the intended transgene insertion site can give rise to a sub-population of rescued lines that lack the transgene. In order to improve and accelerate the transformation pipeline for C. reinhardtii, we have created a novel recipient line, HNT6, carrying an engineered deletion in exon 3 of psaA, which encodes one of the core subunits of photosystem I (PSI). Such PSI mutants are highly light-sensitive allowing faster recovery of transformant colonies by selecting for light-tolerance on acetate-containing media, rather than phototrophic growth on minimal media. The deletion extends to a site upstream of psaA-3 that serves as a neutral locus for transgene insertion, thereby ensuring that all of the recovered colonies are transformants containing the transgene. We demonstrate the application of HNT6 using a luciferase reporter.

Transgenic Microalgae Expressing Double-Stranded RNA as Potential Feed Supplements for Controlling White Spot Syndrome in Shrimp Aquaculture

Viral infection of farmed fish and shellfish represents a major issue within the aquaculture industry. One potential control strategy involves RNA interference of viral gene expression through the oral delivery of specific double-stranded RNA (dsRNA). In previous work, we have shown that recombinant dsRNA can be produced in the chloroplast of the edible microalga Chlamydomonas reinhardtii and used to control disease in shrimp. Here, we report a significant improvement in antiviral dsRNA production and its use to protect shrimp against white spot syndrome virus (WSSV). A new strategy for dsRNA synthesis was developed that uses two convergent copies of the endogenous rrnS promoter to drive high-level transcription of both strands of the WSSV gene element in the chloroplast. Quantitative RT-PCR indicated that ~119 ng dsRNA was produced per liter of culture of the transgenic microalga. This represents an ~10-fold increase in dsRNA relative to our previous report. The engineered alga was assessed for its ability to prevent WSSV infection when fed to shrimp larvae prior to a challenge with the virus. The survival of shrimp given feed supplemented with dried alga containing the dsRNA was significantly enhanced (~69% survival) relative to a negative control (<10% survival). The findings suggest that this new dsRNA production platform could be employed as a low-cost, low-tech control method for aquaculture.

Application of ionizing radiation as an elicitor to enhance the growth and metabolic activities in Chlamydomonas reinhardtii

Chlamydomonas reinhardtii is a eukaryotic, unicellular photosynthetic organism and a potential algal platform for producing biomass and recombinant proteins for industrial use. Ionizing radiation is a potent genotoxic and mutagenic agent used for algal mutation breeding that induces various DNA damage and repair responses. In this study, however, we explored the counterintuitive bioeffects of ionizing radiation, such as X- and γ-rays, and its potential as an elicitor to facilitate batch or fed-batch cultivation of Chlamydomonas cells. A certain dose range of X- and γ-rays was shown to stimulate the growth and metabolite production of Chlamydomonas cells. X- or γ-irradiation with relatively low doses below 10 Gy substantially increased chlorophyll, protein, starch, and lipid content as well as growth and photosynthetic activity in Chlamydomonas cells without inducing apoptotic cell death. Transcriptome analysis demonstrated the radiation-induced changes in DNA damage response (DDR) and various metabolic pathways with the dose-dependent expression of some DDR genes, such as CrRPA30, CrFEN1, CrKU, CrRAD51, CrOASTL2, CrGST2, and CrRPA70A. However, the overall transcriptomic changes were not causally associated with growth stimulation and/or enhanced metabolic activities. Nevertheless, the radiation-induced growth stimulation was strongly enhanced by repetitive X-irradiation and/or subsequent cultivation with an inorganic carbon source, i.e., NaHCO₃, but was significantly inhibited by treatment of ascorbic acid, a scavenger of reactive oxygen species (ROS). The optimal dose range of X-irradiation for growth stimulation differed by genotype and radiation sensitivity. Here, we suggest that ionizing radiation within a certain dose range determined by genotype-dependent radiation sensitivity could induce growth stimulation and enhance metabolic activities, including photosynthesis, chlorophyll, protein, starch, and lipid synthesis in Chlamydomonas cells via ROS signaling. The counterintuitive benefits of a genotoxic and abiotic stress factor, i.e., ionizing radiation, in a unicellular algal organism, i.e., Chlamydomonas, may be explained by epigenetic stress memory or priming effects associated with ROS-mediated metabolic remodeling.

Simultaneous Production of a Virus-Like Particle Linked to dsRNA to Enhance dsRNA Delivery for Yellow Head Virus Inhibition

A co-expressed Penaeus stylirostris densovirus (PstDNV) capsid and dsRNA specific to the yellow head virus (YHV) protease (CoEx cpPstDNV/dspro) has been shown to suppress YHV replication in the Pacific white-legged shrimp (Litopenaeus vannamei). However, maintaining two plasmids in a single bacterial cell is not desirable; therefore, a single plasmid harboring both the PstDNV capsid and the dsRNA-YHV-pro gene was constructed under the regulation of a single T7 promoter, designated pET28a-Linked cpPstDNV-dspro. Following induction, this novel construct expressed an approximately 37-kDa recombinant protein associated with a roughly 400-bp dsRNA (Linked cpPstDNV-dspro). Under a transmission electron microscope, the virus-like particles (VLP; Linked PstDNV VLPs-dspro) obtained were seen to be monodispersed, similar to the native PstDNV virion. A nuclease digestion assay indicated dsRNA molecules were both encapsulated and present outside the Linked PstDNV VLPs-dspro. In addition, the amount of dsRNA produced from this strategy was higher than that obtained with a co-expression strategy. In a YHV infection challenge, the Linked PstDNV VLPs-dspro was more effective in delaying and reducing mortality than other constructs tested. Lastly, the linked construct provides protection for the dsRNA cargo from nucleolytic enzymes present in the shrimp hemolymph. This is the first report of a VLP carrying virus-inhibiting dsRNA that could be produced without disassembly and reassembly to control virus infection in shrimp.

Potential dsRNAs can be delivered to aquatic for defense pathogens

The use of antibiotics to facilitate resistance to pathogens in aquatic animals is a traditional method of pathogen control that is harmful to the environment and human health. RNAi is an emerging technology in which homologous small RNA molecules target specific genes for degradation, and it has already shown success in laboratory experiments. However, further research is needed before it can be applied in aquafarms. Many laboratories inject the dsRNA into aquatic animals for RNAi, which is obviously impractical and very time consuming in aquafarms. Therefore, to enable the use of RNAi on a large scale, the methods used to prepare dsRNA need to be continuously in order to be fast and efficient. At the same time, it is necessary to consider the issue of biological safety. This review summarizes the key harmful genes associated with aquatic pathogens (viruses, bacteria, and parasites) and provides potential targets for the preparation of dsRNA; it also lists some current examples where RNAi technology is used to control aquatic species, as well as how to deliver dsRNA to the target hydrobiont.

CpPosNeg: A positive-negative selection strategy allowing multiple cycles of marker-free engineering of the Chlamydomonas plastome

The chloroplast represents an attractive compartment for light-driven biosynthesis of recombinant products, and advanced synthetic biology tools are available for engineering the chloroplast genome ( = plastome) of several algal and plant species. However, producing commercial lines will likely require several plastome manipulations. This presents issues with respect to selectable markers, since there are a limited number available, they can be used only once in a serial engineering strategy, and it is undesirable to retain marker genes for antibiotic resistance in the final transplastome. To address these problems, we have designed a rapid iterative selection system, known as CpPosNeg, for the green microalga Chlamydomonas reinhardtii that allows creation of marker-free transformants starting from wild-type strains. The system employs a dual marker encoding a fusion protein of E. coli aminoglycoside adenyltransferase (AadA: conferring spectinomycin resistance) and a variant of E. coli cytosine deaminase (CodA: conferring sensitivity to 5-fluorocytosine). Initial selection on spectinomycin allows stable transformants to be established and driven to homoplasmy. Subsequent selection on 5-fluorocytosine results in rapid loss of the dual marker through intramolecular recombination between the 3'UTR of the marker and the 3'UTR of the introduced transgene. We demonstrate the versatility of the CpPosNeg system by serial introduction of reporter genes into the plastome.

Lipophilic and Hydrophilic Compounds from Arthrospira platensis and Its Effects on Tissue and Blood Cells—An Overview

The cyanobacterium Arthrospira platensis (Spirulina platensis) is a natural source of considerable amounts of ingredients that are relevant for nutra- and pharmaceutical uses. Different hydrophilic and hydrophobic substances can be obtained by extraction from the biomass. The respective extraction techniques determine the composition of substances in the extract and thus its biological activity. In this short review, we provide an overview of the hydrophilic compounds (phenols, phycobiliproteins, polysaccharides, and vitamins) and lipophilic ingredients (chlorophylls, vitamins, fatty acids, and glycolipids) of Arthrospira platensis. The principal influences of these substances on blood and tissue cells are briefly summarized.

Current Status and Perspective on the Use of Viral-Based Vectors in Eukaryotic Microalgae

During the last two decades, microalgae have attracted increasing interest, both commercially and scientifically. Commercial potential involves utilizing valuable natural compounds, including carotenoids, polysaccharides, and polyunsaturated fatty acids, which are widely applicable in food, biofuel, and pharmaceutical industries. Conversely, scientific potential focuses on bioreactors for producing recombinant proteins and developing viable technologies to significantly increase the yield and harvest periods. Here, viral-based vectors and transient expression strategies have significantly contributed to improving plant biotechnology. We present an updated outlook covering microalgal biotechnology for pharmaceutical application, transformation techniques for generating recombinant proteins, and genetic engineering tactics for viral-based vector construction. Challenges in industrial application are also discussed.

RNA Interference-Based Pesticides and Antiviral Agents: Microbial Overproduction Systems for Double-Stranded RNA for Applications in Agriculture and Aquaculture

RNA interference (RNAi)-based pesticides are pest control agents that use RNAi mechanisms as the basis of their action. They are regarded as environmentally friendly and are a promising alternative to conventional chemical pesticides. The effective substance in RNAi-based pesticides is double-stranded RNA (dsRNA) designed to match the nucleotide sequence of a target essential gene of the pest of concern. When taken up by the pest, this exerts an RNAi effect and inhibits some vital biochemical/biological process in the pest. dsRNA products are also expected to be applied for the control of viral diseases in aquaculture by RNAi, especially in shrimp farming. A critical issue in the practical application of RNAi agents is that production of the dsRNA must be low-cost. Here, we review recent methods for microbial production of dsRNAs using representative microorganisms (Escherichia coli, Pseudomonas syringae, Corynebacterium glutamicum, Chlamydomonas reinhardtii, and others) as host strains. The characteristics of each dsRNA production system are discussed.

Broad Spectrum Algae Compounds Against Viruses

The pharmaceutical industry is currently trying to develop new bioactive compounds to inactivate both enveloped and non-enveloped viruses for therapeutic purposes. Consequently, microalgal and macroalgal bioactive compounds are being explored by pharmaceutical, as well as biotechnology and food industries. In this review, we show how compounds produced by algae include important candidates for viral control applications. We discuss their mechanisms of action and activity against enveloped and non-enveloped viruses, including those causing infections by enteric, parenteral, and respiratory routes. Indeed, algal products have potential in human and animal medicine.

Advances in the Development of Microbial Double-Stranded RNA Production Systems for Application of RNA Interference in Agricultural Pest Control

RNA interference (RNAi) is a valuable and revolutionary technology that has been widely applied in medicine and agriculture. The application of RNAi in various industries requires large amounts of low-cost double-stranded RNA (dsRNA). Chemical synthesis can only produce short dsRNAs; long dsRNAs need to be synthesized biologically. Several microbial chassis cells, such as Escherichia coli, Saccharomyces cerevisiae, and Bacillus species, have been used for dsRNA synthesis. However, the titer, rate of production, and yield of dsRNA obtained by these microorganism-based strategies is still low. In this review, we summarize advances in microbial dsRNA production, and analyze the merits and faults of different microbial dsRNA production systems. This review provides a guide for dsRNA production system selection. Future development of efficient microbial dsRNA production systems is also discussed.

Advanced Applications for Protein and Compounds from Microalgae

Algal species still show unrevealed and unexplored potentiality for the identification of new compounds. Photosynthetic organisms represent a valuable resource to exploit and sustain the urgent need of sustainable and green technologies. Particularly, unconventional organisms from extreme environments could hide properties to be employed in a wide range of biotechnology applications, due to their peculiar alleles, proteins, and molecules. In this review we report a detailed dissection about the latest and advanced applications of protein derived from algae. Furthermore, the innovative use of modified algae as bio-reactors to generate proteins or bioactive compounds was discussed. The latest progress about pharmaceutical applications, including the possibility to obtain drugs to counteract virus (as SARS-CoV-2) were also examined. The last paragraph will survey recent cases of the utilization of extremophiles as bio-factories for specific protein and molecule production.

Efficient production of long double-stranded RNAs applicable to agricultural pest control by Corynebacterium glutamicum equipped with coliphage T7-expression system

Abstract

RNA-based pesticides exert their function by suppressing the expression of an essential gene in the target pest through RNA interference caused by double-stranded RNA (dsRNA). Here, we selected target genes for growth suppression of the solanaceous crop pests ladybird beetle (Henosepilachna vigintioctopunctata) and Colorado potato beetle (Leptinotarsa decemlineata)-the death-associated inhibitor of apoptosis protein 1 gene (diap1), and an orthologous gene of the COPI coatomer protein complex (copI), respectively. We constructed a cost-competitive overproduction system for dsRNA using Corynebacterium glutamicum as a host bacterium. The dsRNA expression unit was equipped with two sets of promoters and terminators derived from coliphage T7, and the convergent expression system was designed to be selectively transcribed by T7 RNA polymerase. This expression system efficiently overproduced both target dsRNAs. On culture in a jar fermentor, the yield of diap1-targeting dsRNA (approximately 360 bp) was > 1 g per liter of culture. Long-chain diap1-targeting dsRNAs (up to around 1 kbp) could be produced without a substantial loss of efficiency. dsRNA accumulated in C. glutamicum significantly suppressed larval growth of H. vigintioctopunctata. The dsRNA expression technology developed here is expected to substantially reduce dsRNA production costs. Our method can be applied for a wide range of industrial uses, including agricultural pest control.

Key points

• Overexpression of dsRNA was achieved in C. glutamicum using a coliphage T7 system.

• The best strain produced > 1 g/L of the target dsRNA species, for use as an insecticide.

• The developed system efficiently produced long dsRNA species, up to ~ 1 kbp.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-021-11324-9.

Evaluation of Microalgae as Immunostimulants and Recombinant Vaccines for Diseases Prevention and Control in Aquaculture

Microalgae are often used as nutritional supplements for aquatic animals and are widely used in the aquaculture industry, providing direct or indirect nutrients for many aquatic animals. Microalgae are abundant in nature, of high nutritional value, and some of them are non-toxic and rich in antioxidants so that they can be explored as a medicinal carrier for human or animals. Natural wild-type microalgae can be adopted as an immunostimulant to enhance non-specific immune response and improve growth performance, among which Haematococcus pluvialis, Arthrospira (Spirulina) platensis, and Chlorella spp. are commonly used. At present, there have been some successful cases of using microalgae to develop oral vaccines in the aquaculture industry. Researchers usually develop recombinant vaccines based on Chlamydomonas reinhardtii, Dunaliella salina, and cyanobacteria. Among them, in the genetic modification of eukaryotic microalgae, many examples are expressing antigen genes in chloroplasts. They are all used for the prevention and control of single infectious diseases and most of them are resistant to shrimp virus infection. However, there is still no effective strategy targeting polymicrobial infections and few commercial vaccines are available. Although several species of microalgae are widely developed in the aquaculture industry, many of them have not yet established an effective and mature genetic manipulation system. This article systematically analyzes and discusses the above problems to provide ideas for the future development of highly effective microalgae recombinant oral vaccines.

The phosphite oxidoreductase gene, ptxD as a bio-contained chloroplast marker and crop-protection tool for algal biotechnology using Chlamydomonas

Edible microalgae have potential as low-cost cell factories for the production and oral delivery of recombinant proteins such as vaccines, anti-bacterials and gut-active enzymes that are beneficial to farmed animals including livestock, poultry and fish. However, a major economic and technical problem associated with large-scale cultivation of microalgae, even in closed photobioreactors, is invasion by contaminating microorganisms. Avoiding this requires costly media sterilisation, aseptic techniques during set-up and implementation of 'crop-protection' strategies during cultivation. Here, we report a strain improvement approach in which the chloroplast of Chlamydomonas reinhardtii is engineered to allow oxidation of phosphite to its bio-available form: phosphate. We have designed a synthetic version of the bacterial gene (ptxD)-encoding phosphite oxidoreductase such that it is highly expressed in the chloroplast but has a Trp→Opal codon reassignment for bio-containment of the transgene. Under mixotrophic conditions, the growth rate of the engineered alga is unaffected when phosphate is replaced with phosphite in the medium. Furthermore, under non-sterile conditions, growth of contaminating microorganisms is severely impeded in phosphite medium. This, therefore, offers the possibility of producing algal biomass under non-sterile conditions. The ptxD gene can also serve as a dominant marker for genetic engineering of any C. reinhardtii strain, thereby avoiding the use of antibiotic resistance genes as markers and allowing the 'retro-fitting' of existing engineered strains. As a proof of concept, we demonstrate the application of our ptxD technology to a strain expressing a subunit vaccine targeting a major viral pathogen of farmed fish.

Recent Advances in Microalgal Bioactives for Food, Feed, and Healthcare Products: Commercial Potential, Market Space, and Sustainability

To combat food scarcity as well as to ensure nutritional food supply for sustainable living of increasing population, microalgae are considered as innovative sources for adequate nutrition. Currently, the dried biomass, various carotenoids, phycocyanin, phycoerythrin, omega fatty acids, and enzymes are being used as food additives, food coloring agents, and food supplements. Apart from nutritional importance, microalgae are finding the place in the market as "functional foods." When compared to the total market size of food and feed products derived from all the possible sources, the market portfolio of microalgae-based products is still smaller, but increasing steadily. On the other hand, the genetic modification of microalgae for enhanced production of commercially important metabolites holds a great potential. However, the success of commercial application of genetically modified (GM) algae will be defined by their safety to human health and environment. In view of this, the present study attempts to highlight the industrially important microalgal metabolites, their production, and application in food, feed, nutraceuticals, pharmaceuticals, and cosmeceuticals. The current and future market trends for microalgal products have been thoroughly discussed. Importantly, the safety pertaining to microalgae cultivation and consumption, and regulatory issues for GM microalgae have also been covered.

Microalgal Derivatives as Potential Nutraceutical and Food Supplements for Human Health: A Focus on Cancer Prevention and Interception

Epidemiological studies are providing strong evidence on beneficial health effects from dietary measures, leading scientists to actively investigate which foods and which specific agents in the diet can prevent diseases. Public health officers and medical experts should collaborate toward the design of disease prevention diets for nutritional intervention. Functional foods are emerging as an instrument for dietary intervention in disease prevention. Functional food products are technologically developed ingredients with specific health benefits. Among promising sources of functional foods and chemopreventive diets of interest, microalgae are gaining worldwide attention, based on their richness in high-value products, including carotenoids, proteins, vitamins, essential amino acids, omega-rich oils and, in general, anti-inflammatory and antioxidant compounds. Beneficial effects of microalgae on human health and/or wellness could in the future be useful in preventing or delaying the onset of cancer and cardiovascular diseases. During the past decades, microalgal biomass was predominately used in the health food market, with more than 75% of the annual microalgal biomass production being employed for the manufacture of powders, tablets, capsules or pastilles. In this review, we report and discuss the present and future role of microalgae as marine sources of functional foods/beverages for human wellbeing, focusing on perspectives in chemoprevention. We dissected this topic by analyzing the different classes of microalgal compounds with health outputs (based on their potential chemoprevention activities), the biodiversity of microalgal species and how to improve their cultivation, exploring the perspective of sustainable food from the sea.