Abstract
Microalgae are one of the less-explored, nutritional treasures of the marine biosphere. With the emergence of algal technology, research has been shifting slowly towards exploring the nutraceutical values of these microorganisms, and microalgae like Chlorella vulgaris are gaining high market value. In addition, with the increasing demand for vegan source of omega-3 fatty acids, the Chlorella vulgaris biomass may be considered as a potential alternative. In this study optimization of various parameters such as culturing conditions, media composition, pH, RPM, inoculum percentage, carbon source, concentration of glucose, and salt to enhance the yield has been carried out. The best results were obtained at pH 7 with an inoculum percentage of 5 and the addition of 1.5 gm of NaCl and glucose enhanced the yield of biomass, protein, and lipid in Chlorella vulgaris. Optimized conditions gave a maximum yield of biomass, lipids, and protein. Among the lipids, omega-3 fatty acids have high nutraceutical value. In the fatty acid methyl esters, DHA and EPA were found to be 2.9% and 0.55 %. Estimation of omega-3 fatty acids was done using TLC and GC-MS. The Omega-3 fatty acids and dietary proteins extracted from Chlorella vulgaris can serve as an alternate vegan source for nutritional supplements.
Download the full article as PDF here:
A Study on Chlorella Biomass as a Vegan Source for Omega-3 Fatty Acids and Dietary Proteins
Introduction
Omega-3 fatty acids are a category of fatty acids that the human body is unable to produce on its own. These are necessary fats that must be obtained from external sources. Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) are the two forms of omega-3 that are majorly obtained from fish Biomass. Plants contain omega-3 fatty acids in the form of alpha-linolenic acid (ALA). Due to the abundance of non-vegetarian sources of omega-3 fatty acids and the scarcity of vegan alternatives, omega-3 fatty acid supplements derived from fish oil are not practical for vegetarians, who are unable to meet their daily needs for omega-3 fattyacids. Since fishes spawn in a specific season, the biomass of fish is not available year-round for the production of omega-3 fatty acids. Fish from contaminated waterways may have accumulated mercury, which can cause cancer[1]. Fish and fish oil allergies exist in certain people. Omega-3 fatty acid supplements derived from fish oil are not feasible for such individuals[2]. Furthermore, some people have been known to develop gastritis and indigestion after taking fish oil. Microalgae hold great potential for the sustainable production of high-value chemicals, feed, and biofuels. Microalgae, such as Spirulina and Chlorella, are possible sources of proteins and lipids that can be utilized to make functional meals that enhance human health [3].
When compared to other microalgae, Chlorella vulgaris has a high market value, with a market scope analogous to Spirulina (Arthrospira platensis). However, the added advantage of Chlorella vulgaris over Spirulina is that it does not have a cytotoxic effect on healthy cells. The Spirulina produce a compound called microcystin which is toxic to liver cells [4]. Most of the applications of C. vulgaris have been on its metabolism of lipids, proteins, and carbohydrates[5]. They are commercially important as they can produce a variety of essential and non-essential amino acids [6]. Apart from its nutritional value Chlorella vulgaris has also been known for its medical applications like cardioprotective properties [7], immunomodulatory effects [8], anticancer properties [9] and antidiabetic properties [10]. Protein makes up to 45-58% of the dry weight of the Chlorella biomass of which 20% of the protein is bound to the cell wall supporting the structural integrity of the cell and also serves as a transporter.
The total protein content may vary 12-120 kDa of which the majority lies in the range of 39-75 kDa. Lipids constitute around 5-40% of the Chlorella vulgaris dry weight. The lipids are present in the form of glycolipids, waxes, hydrocarbons, fatty acids, and phospholipids. These are synthesized in the chloroplasts and directed towards the cell membrane and cell wall [11]. Concerning the type of fatty acids in C. vulgaris, it has been noted that 70.18% are saturated fatty acids (SFA),16.85% are monounsaturated fatty acids (MUFA) and 8.72% are polyunsaturated fatty acids (PUFA) hence, it can be considered as a storehouse of various fatty acids [12]. 2117 throughout the year and it takes only a few days to produce the culture.
The micrometer size and its unicellular nature contribute to a high surface-to-volume ratio giving efficient nutrient utilization and metabolite production[15]. It is a better alternative for people with allergies to fish and fish oil. In addition, there is no wastage in this process, as the by-products can be used as poultry/cattle feed, as they have high nutritional value. In this study, the optimization of physical parameters and media for maximal production of lipids and proteins has been carried out through sustainable and cost-efficient processes using Chlorella vulgaris. The lipids and proteins that come as a byproduct in culturing processes are of high nutraceutical and pharmaceutical significance.
Microalgae can be explored as a solution for the problems related to the production of Omega-3 fatty acids from fish biomass. In comparison to higher-level plants, the growth of microalgae is quicker, they can grow in harsh conditions and give better metabolite yield[13]. Omega 3 fatty acids are produced in higher amounts in the microalgae Chlorella vulgaris[14]. Microalgal biomass is available throughout the year and it takes only a few days to produce the culture. The micrometer size and its unicellular nature contribute to a high surface-to-volume ratio giving efficient nutrient utilization and metabolite production[15]. It is a better alternative for people with allergies to fish and fish oil. In addition, there is no wastage in this process, as the by-products can be used as poultry/cattle feed, as they have high nutritional value. In this study, the optimization of physical parameters and media for maximal production of lipids and proteins has been carried out through sustainable and cost-efficient processes using Chlorella vulgaris. The lipids and proteins that come as a byproduct in culturing processes are of high nutraceutical and pharmaceutical significance.
Revival and culturing of the microalgal strain
The pure culture of Chlorella vulgaris was obtained from Biopol Biosciences, Bangalore. The microalgae was revived in the BG11 media for further experiments. To find the optimal growth of the microalgae a comparative study was made between the growth, using an incubator shaker with 200 rpm at room temperature and plant tissue culture setup [16]. 200 ml of BG11 media was autoclaved and 50μl of inoculum was added to both the media under aseptic conditions and kept for incubation in their respective conditions. Once the microalgal growth was observed they were added with 40% glycerol and cryopreserved at -80⁰C and used for further experiments.
Ananya N Nayak, Dhamodhar Prakash, Akash S, Renju Raju. A Study on Chlorella Biomass as a Vegan Source for Omega-3 Fatty Acids and Dietary Proteins. Current Trends in Biotechnology and Pharmacy, Vol. 19(1) 2116-2129, January 2025, ISSN 0973-8916 (Print), 2230-7303 (Online)
DOI: 10.5530/ctbp.2025.1.2
