Chlorella sp. is a member of the Chlorophyceae class under the Chlorophyta division (Imelda et al., 2018). The cells of Chlorella sp. are spherical and have sizes between 2 and 10 m. The cells contain a twofold phospholipid-based enclosing membrane on their cup-shaped chloroplast . A thick cell wall (100–200 nm) made of chitin and cellulose and possessed by Chlorella sp. offers both chemical and mechanical defence. When growing properly, Chlorella sp. has a straightforward life cycle with metabolic activities like those of higher plants (Sydney et al., 2019). Because of its strong economic characteristics, including GRAS, quick cultivation, and high biomass, Chlorella sp. dominates the microalgal market (Silva et al., 2019).
Chlorella species has been used in a number of sectors, including biofuel, food, cosmetics, and agriculture. 51–58% of the protein, 14–22% of the lipid, 12–17% of the carbs, 4-5% of the nucleic acids, and 0.4% of the fibre in this species of alga are. Amino acids make up 60% of the protein content of chlorella. As a result, the human body can immediately absorb it (Safi et al., 2014). In addition, Chlorella sp. accumulates biologically active substances that come from secondary metabolism, such as phenolic compounds and pigments. According to several research, Chlorella bioactive components may have therapeutic benefits such as anti-inflammatory, anti-cancer, anti-cancer, and anti-hyperglycemia properties. They can now be utilized as a source of nutritional components (Morais et al., 2015).
People are far more conscious now than they were ten years ago that diet directly affects health. As a result, more and more study is being done on components of natural origin with significant biological value. Chlorella has received a lot of attention for being developed as a creative source for new foods due to its great nutritional content. Additionally, chlorella can be employed as functional foods, which are goods that offer certain health benefits above and beyond the needs for essential nutrients. Thus, by lowering the risk of illnesses, chlorella ingestion may enhance human wellbeing and quality of life (Potin et al., 2017) (Widyaningrum et al., 2021).
Chlorella's cell walls are thick and solid, however the structure of the walls can differ significantly between species (Gerken et al., 2013). The stiffness defends the cell's integrity and serves as a barrier against intruders and the hostile environment. Depending on the stage of growth, it varies.
It is a gel-like substance that is contained within the cell membrane wall and is made up of water, soluble proteins, minerals, and other substances. It also contains internal organelles from C. vulgaris, including a single chloroplast, a tiny nucleus, and mitochondria.
In addition to the respiratory system and genetic material, mitochondria are surrounded by a two-layer membrane, the outermost part of which covers all organelles and is composed equally of phospholipids and proteins. The inner layer, on the other hand, is made up of three times as many proteins as phospholipids and covers a region inside the mitochondria known the matrix.
A single chloroplast with two phospholipid-based enclosing membranes can be seen in C. vulgaris. The inner membrane has a number of roles in the transport of proteins while the outside membrane is permeable to ions and metabolites. When growing conditions are poor, starch granules made of amylopectin and amylose may develop into the chloroplast. The pyrenoid, which is the site of carbon dioxide fixation, has significant concentrations of the enzyme ribulose-1,5-bisphosphate carboxylase oxygenase. A collection of fused thylakoids, which are also stored in the chloroplast, is where chlorophyll, the main pigment, is generated. Lutein, another pigment, is coloured differently and is covered up by chlorophyll. The chloroplast and cytoplasm are where nitrogen stress is most concentrated during lipid globules (Ibrahim and Elbaily, 2020).
Chlorella Growth Factor:
The chlorella nucleus contains a special nutritional combination called Chlorella Growth Factor. As a result of photosynthesis, chlorella cells rapidly divide into four new cells per 20 hours. In humans, this rapid rate of CGF development aids in the repair of injured cells and reduces the ageing cycle (Imelda et al., 2018).
Many researchers and scientists have found that CGF, a water-soluble extract from Chlorella, stimulates the growth of animals and microorganisms. CGF includes sulphur, glycoprotein, nucleic acid-polysaccharides, nucleotide-peptides, and other nutrients that are essential for the body's growth, immunity, and other health advantages. . Numerous scientists, academics, and doctors continue to study its scientific and distinctive component structure, which is drawing attention from a wide audience worldwide. It possesses anti-cancer effects in its nucleotide-peptide. Since CGF is practically flavourless and odourless, it enhances food flavour and promotes the growth of lactobacillus, which is present in lactic acid beverages, natto, miso, soy sauce, and soybean paste, among other healthy and flavorful foods (Abdolbaghian et al., 2021).
Worldwide commercial availability of dietary supplement products made from chlorella species, which may be mass-cultivated. However, only a few years ago did commercial production of their biomass begin. Famous scientist and botanist Dr. Martinus Willem Beijerinck found and described Chlorella vulgaris in 1890. In 1903, a different Chlorella species was discovered and given the name C. pyrenoidosa, which is differentiated by the presence of pyrenoids in chloroplasts. Since then, approximately 20 Chlorella species and over 100 strains have been identified (Bito et al., 2020). Currently, the three Chlorella species—C. vulgaris, C. lobophora, and C. sorokiniana—are classified as separate species . A subspecies called C. sorokiniana was discovered by Sorokin in 1953. The original theory was that it was a mutant of C. pyrenoidosa that was thermotolerant (Lizzul et al., 2018).
The organism formerly known as C. pyrenoidosa—the focus of a number of studies—is now known as C. sorokiniana. When Chlorella was first used as a food source during a worldwide food shortage in the 1950s, studies on its nutritional significance for human health started. Chlorella was first created and eaten in Asia, primarily in Japan, and subsequently it spread to other parts of the world as a nutritional supplement (Sydney et al., 2019). Chlorella is grown for consumption in foods and as a source of its intrinsic chemicals in commercial production. C. vulgaris and C. pyrenoidosa are produced as industrial sources for dietary supplements using large-scale farming technologies. Studies have revealed that chlorella cells contain a wide range of nutrients and bioactive substances that support human health and prevent several diseases, indicating that natural substances derived from chlorella may serve as an alternative to synthetic substances or medications. Between species and cultivation conditions, chlorella's natural chemical concentration differs significantly (Bito et al., 2020).
Composition of Chlorella:
The primary element of microalgae is protein. They perform crucial functions in cell repair, maintenance, and growth. They work as chemical signals, cellular motors, activity controllers, and defensive mechanisms against invading forces. Total protein content in mature C. vulgaris accounts for 42–58% of the dry weight of the biomass. Depending on the environment for growth, it changes. Nearly 20% of all proteins are going for the cell wall, more than 50% are internal, and 30% move in and out of the cell. Proteins play many different roles. According to the amino acid composition of a protein determines its nutritional quality (Safi et al., 2013).
Like the most of microalgae, C., According to the fact that C. vulgaris cells included both required and non-essential amino acids, it matches favourably and even superior with the standard profile for human nutrition put forward by the Food and Agricultural Organization (FAO) and World Health Organization (WHO). Additionally, the method used to extract the proteins from C. vulgaris seems to have great emulsifying properties (Ursu et al., 2014). In comparison to the commercial substances, it is excellent.
A class of compounds known as carbohydrates includes polysaccharides like cellulose and starch as well as reducing sugars. The most dominant polysaccharide in C. vulgaris is starch. It typically found in the chloroplast and contains both amylose and amylopectin. They work with carbohydrates to provide the cells with energy storage. The cell wall of C. vulgaris contains cellulose, a structural polysaccharide with high resilience that serves as a fibrous preservation barrier (Alavijeh et al., 2020). Additionally, the 1- 3 glycan is one of the most significant polysaccharides present in C. vulgaris, and it has numerous nutritional and health advantages. Additionally, C. vulgaris has a significantly thick cell wall that is mostly made of a chitosan-like layer, proteins, and other components like lipids, cellulose, hemicellulose and minerals.
A heterogeneous class of chemicals known as Lipids is defined by their solubility in non-polar solvents and relative insolubility in water rather than by their structure. Under ideal growth conditions, the lipid content of C. vulgaris reaches 5- 40% of the dry weight of the biomass. They mostly consist of hydrocarbons, glycolipids, waxes, phospholipids, a minor amount of free fatty acids, and hydrocarbons. However, under poor development conditions, the lipid content—which is primarily made up of triacylglycerol—can increase to 58% (Chia et al., 2013) (Ibrahim and Elbaily, 2020).
Phenolic compounds support the chemical defences used by microalgae against metal toxicity, bacterial colonisation, and UV exposure. Additionally, phenolic compounds shield critical cell components from free radicals, including cell membranes, nucleic acids, structural proteins, and cellular enzymes. Phloroglucinol, ferulic acid, apigenin, and p-Coumaric acid are phenolic substances identified in C. vulgaris. The phenolic substances ferulic acid, cinnamic acid, caffeic acid, and p-Coumaric acid were isolated from Chlorella sorokiniana. Antioxidant, anti-tumor, and antibacterial characteristics are only a few of the medical benefits of phenolic chemicals. Previous research indicated that the predominant source of the antioxidative characteristics identified by analysis came from the phenolic chemicals found in chlorella. By blocking lipid peroxidation on the cell membrane, eliminating cellular free radicals, and guarding against DNA damage, chlorella phenolic chemicals may stop the carcinogenesis of liver cells. A study revealed that phenolic chemicals from C. vulgaris found in methanol extract have antibacterial activity (Widyaningrum et al., 2021).
All of the vitamins that people need are included in commercially available chlorella products, including vitamins B1, B2, B6, B12, biotin, pantothenic acid, niacin, folate, C, D2, E, and K, as well as - and -carotenes. Vitamins D2 and B12, each of which are well recognized to be lacking in plants, are present in significant quantities in chlorella products. Compared to spinach, commercially available chlorella (C. vulgaris) products have more folate (around 2.5 mg/100 g dry weight). Deficits in vitamin B12 and folate cause the serum homocysteine level to increase, which is linked to cardiovascular disorders (Woortman et al., 2020).
Minerals that are needed by humans can be found in commercially marketed chlorella products. Chlorella products in particular have high levels of potassium (986 mg/100 g dry weight) and iron (104 mg/100 g dry weight). These minerals prevent anaemia and hypertension when consumed enough. In the body, iron is involved in the processes of breathing, energy production, DNA synthesis, and cell division (Camaschella, 2015).
Due to their ability to chelate iron and create an insoluble complex, phytates found in grains effectively block the intestinal absorption of iron. Therefore, iron deficiency anaemia may be a problem for those who follow vegan and vegetarian diets (Gibson et al., 2018). Chlorella supplementation and the prevention of iron-deficiency anaemia have both been the subject of studies in rats and people. Oral Chlorella supplementation (6 g/day) for 12–18 weeks lowered anaemia indicators in a cohort of 32 pregnant women in the 2nd and 3rd trimester comparison to the control group. This suggests that taking chlorella supplements considerably lowers the risk of anaemia related to pregnancy (Nakano et al., 2010).
The most prevalent found naturally pigments in plants contain secondary metabolites called carotenoids that are involved in a number of biological functions. These include photomorphogenesis, photoprotection, and photosynthesis. They also act as food colouring and essential nutrients for humans, like provitamin A and antioxidants. More than 400 different types of carotenoids have been found in living things, but -carotene, astaxanthin, lutein, zeaxanthin, and lycopene are the most well-known (Sathasivam et al., 2019.Chlorella total carotenoids contents are around 1.3%. Lutein is said to be the main carotenoid produced by C. vulgaris.
Benefit of Chlorella:
Food source for human:
Chlorella has all nine essential amino acids and is high in protein (up to 68%). Fatty acids, carotenoids, dietary fibres, vitamins, minerals, and other bioactive substances are also present. This makes this algae a delicious food with superior nutritional value. The long history of using chlorella as a nutrient-dense food dates back to the World Wars' periods of food scarcity. Chlorella is mostly produced in China and Japan, with about 3,500 tonnes of biomass produced each year as of 2005. One of the few microalgae on the market is C. vulgaris, which is used as a food additive, colourant (C. vulgaris after carotenogenesis), and food emulsion. These goods are available in a variety of formats, including tablets, capsules, powder, and extracts (Silva et al., 2019).
Despite all the health advantages that C. vulgaris and other microalgae can offer, they are more often regarded as nutraceuticals than food products because there are no official regulations that are uniformly explicit about the standards of quality and needs for microalgae. Additionally, C. vulgaris extract demonstrated strong preservation action when combined with chlorella. It has been demonstrated to play significant roles in the treatment of illnesses and their prevention, such as enhancing immune system performance and preventing tumours and cancer, enhancing the impact of hypoglycemia, preventing cognitive deterioration in age-dependent dementia and bringing down blood pressure. Because of its abundant pigments, chlorella is frequently utilised as a natural colourant for human food. According to, adding Chlorella biomass provided cookies a more appealing and creative appearance and improved texture qualities (Liu and Chen, 2014).
Food source for animal:
More recently, chlorella has been used as animal feed. Biomass from nutritional chlorella can be fed to animals direct or used to enrich protozoa like rotifers that are fed to animals in aquaculture. According to estimates, 30% of microalgal production is sold for use in animal feed as a result of the rising demand for foods made from natural ingredients rather than synthetic ones. Due to this, extensive study is being done to identify natural substances that can raise the calibre of animal feeding items. Chlorella is beneficial for fish growth and nutrient improvement when fed to them. One of the most crucial quality factors affecting the market value of fish, especially ornamental fish, is the degree of skin pigmentation. They must consume creatures that contain carotenoids, such as microalgae, in order to produce them because they are unable to produce them on their own (Kotrbáček et al., 2015).
Chlorella is frequently used in aquaculture to colour ornamental fish since it is rich in colours and, based on the species, even keto-carotenoids. Additionally, Chlorella exhibits potential uses in poultry, such as feeding to chickens to colour their egg yolks. Since Chlorella has a hard, inflexible cell wall, it is frequently required to pre-treat it properly in order to speed up the digestion and absorption of its nutrients. Due to this, extensive study is being done to identify natural substances that can raise the standard of animal feeding items. Therefore, under stress, C. vulgaris tends to accumulate significant amounts of carotenoids, and when fed to fish and poultry, it exhibits interesting pigmentation potential for fish flesh and egg yolk, as well as improving health and lengthening animal life (Abdelnour et al., 2019).
Additionally, C. vulgaris demonstrated a defensive impact against high metals and other hazardous substances, significantly lowering the oxidative stress brought on by these harmful substances and raising the antioxidant activity in the bodies of examined animals. They are the primary forces behind the development of microalgae in a wastewater treatment system. So, a procedure that accelerates growth while also reducing water contamination is favourable and promising. Additionally, C. vulgaris performed better in synthetic wastewater when immobilised in alginate beads with bacteria that encourage microalgae development. It was capable of removing 100% of ammonium (NH4) after four consecutive cycles of 4 8 h and 83% of phosphorus after one cycle of 4 8 h. Because of its amazing ability to totally eradicate ammonium and occasionally minor ability to entirely remove phosphorus contained in the medium, C. vulgaris is regarded as one of the finest microalgae for bioremediation of wastewater (Lu et al., 2015).
Application of Chlorella in Functional Food:
Functional foods are those that include one or more substances that can improve the quality of life in addition to being designed to give people the essential nutrients they need. Research on ingredients with high biological value that are of natural origin has been stimulated by the growing demands for such foods. Chlorella is a type of microalga that can be used to create novel products with great potential as functional food components. Chlorella has long been popular as a dietary supplement and nutritious food (Andrade et al., 2018). The human body benefits from the effects of consuming 3 to 10 grammes of chlorella everyday. Recent research has demonstrated that chlorella has a chemical components that is properly balanced. As a result, food products that contain chlorella can improve nutritional value (Rzymski et al., 2019).
Since ancient times, chlorella has been used extensively as a nutritional supplement. Chlorella is available in tablet and powder form, and the microalgal market is flooded with it because of its capacity to bind toxic heavy metals like mercury and expel them from the body. Research has recently been conducted on the creation of food products made from chlorella biomass. Chlorella has been added to a variety of food products, including biscuits, pasta, yoghurt, and croissants (Beheshtipour et al., 2013). These food products now have more functional nutrients, including vital amino acids, antioxidants, polyunsaturated fatty acids, and vitamins thanks to the addition of chlorella biomass. These products are appealing and inventive. Additionally, adding chlorella may increase the probiotics' survivability in fermented dairy products like yoghurt.
Chlorella has a significant potential to be developed as a meal for the future, according to the growing body of research on it as a functional food element. Additionally, there is a significant market for food that helps people stay healthy, feel better, and live better. Thus, it is anticipated that the market for chlorella ingredients will expand and satisfy human nutritional requirements. Another significant obstacle to the expansion of the chlorella business may be the lack of awareness of the benefits of chlorella (Bito et al., 2020).
Microalgae can generate in amounts comparable to those of land plants. In terms of vital sources of food, medicine, building materials, and energy supply, it has long been essential to human survival. Numerous photosynthetic unicellular microalgae are becoming well-known as cutting-edge renewable energy sources that can meet the needs of human activities. Lipids from microalgae can be used as a starting ingredient in the production of biodiesel. Bioethanol or biogas can be made from any leftover, carbohydrate-rich biomass. Furthermore, the entire biomass can be converted directly into crude bio-oil using a variety of thermochemical conversion techniques (Wang et al., 2022).
Lipid accumulation in microalgae often accounts for 20–50% of their dry weight. Under some circumstances, some species can reach up to 80%. These neutral lipids, which can be changed to fatty acid methyl esters (FAMEs) and biodiesel, are primarily triacylglycerols (TAGs) (up to 90–95%). (MacDougall et al., 2011).
Due to their rapid growth and productivity, their, capability to grow on non-arable land using wastewater, ability for using water contaminants and CO2, and the capacity to generate a variety of high-value biological compounds, algae have benefits over first generation biofuels derived from sugar, starch, and vegetable oil (Cheng and Luo, 2022). Biofuels (biodiesel and ethanol) made up 135 billion gallons of the total fuel used for transportation in 2016, or 4%. In addition to having many benefits over petroleum, such as lower CO2 emissions, reduced production costs, and greater sustainability, biodiesel and ethanol are alternatives for petroleum-based diesel and gasoline, respectively (Kushwaha et al., 2022) (Srimongkol et al., 2022).
Chlorella for CO2 Bio-mitigation:
Industrialization and urbanisation have contributed to a significant rise in greenhouse gases (GHGs), primarily carbon dioxide, over the past few of centuries (CO2). It is regarded as one of the primary contributors to both global warming and other significant environmental issues, like ocean acidification (Peter et al., 2018). Globally, several approaches based on chemical, physical, and biological processes have been investigated for lowering CO2 emission levels. One of the most efficient strategies for CO2 capture among them is CO2 bio-fixation through the photosynthetic process (Duarte et al., 2016).
An effective photosynthetic system, like microalgae, may also be beneficial through a variety of uses and offer a sustainable method for reducing CO2. Microalgae grows up to 50 times more quickly than their terrestrial plant counterparts, making them the planet's fastest-growing photosynthetic creatures. They don't need access to arable land, and they use a lot less fresh water. A wide range of culture conditions, including exceptionally high CO2 concentrations, are tolerated by different microalgae (Papazi et al., 2018).
Chlorella vulgaris is a photosynthetic microalga that can change a CO2-rich, unfriendly for humans atmosphere into a hospitable O2-rich atmosphere. It requires extremely high CO2 concentrations for its metabolism. Particularly, CO2 fixation rates of up to 10% were seen in photoautotrophic cultures of Chlorella vulgaris grown in bubble column photobioreactors (Anjos et al., 2013). Chlorella vulgaris is a species that not only tolerates very high CO2 levels, but also dramatically increases its photosynthetic activity at very high CO2 levels (up to 1500 times greater concentration than the ambient air CO2 concentration). Chlorella vulgaris on a wide scale could provide useful biomass while addressing environmental issues, namely CO2-driven climate change. Chlorella vulgaris is not only tolerant of very high CO2 levels, but also needs them for energetic photosynthetic activity that is unaffected by stress. These findings demonstrate how special this microalga is as a technique for battling climate change (Mountourokis et al., 2021).
Conclusions and Future Prospects:
Chlorella is a single-cell bioreactor that uses sunlight to transform carbon dioxide into strong bio compounds like proteins, lipids, and carbohydrates. It is one of the most researched genera of microalgae used in bulk cultivation. Chlorella is a significant source of healthy food for humans to consume due to its richness in protein and other nutritional components, biological safety, and the ability to reproduce and maintain outdoors on a big scale. Chlorella is seen as a possible source of microalgal oils for the creation of biofuels. The pipeline for producing biofuel still faces significant obstacles, including those related to mass growing, harvesting, and drying, disrupting biomass for extracting oil and conversion, and recycling water and nutrients. In comparison to fossil fuels, it renders biofuels made from chlorella capital-intensive and far from economically viable. A prospective step toward a Chlorella production method that is affordable is the integrated manufacturing of biofuels and other potential high-value goods, along with ecologically friendly uses like wastewater treatment and flue gas bio mitigation. Biologists and engineers must work closely together to achieve this. Comprehensive investigations of several prospective strains of Chlorella are being conducted using genomic, transcriptomic, proteomic, lipidomic, and metabolomic techniques as interest in the algae grows. The biological consequences will be revealed once those omics data are available. It makes Chlorella easier to manipulate specifically for more diverse industrial uses.
BioGenesis Chlorella is organically grown in the pristine Great Barrier Reef region of northern Australia. Bathed in golden sunshine the Chlorella thrive in the fresh spring water ponds. We have developed an innovative advanced energy efficient hydrodynamic growth system that replicates a natural river flow. When harvested we apply an advanced biodynamic technology to gently crack the hard outer cell wall making the nutrients fully available.
Australia’s only Licenced Chlorella grower. No.9298. Produced in a USA FDA accredited Bio Secure site.