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Microalgae as a Source of Sustainability
Published in Pau Loke Show, Wai Siong Chai, Tau Chuan Ling, Microalgae for Environmental Biotechnology, 2023
Pik Han Chong, Jian Hong Tan, Joshua Troop
At the end, cyanobacteria are Gram-negative bacteria that obtain energy through photosynthesis. Although it is a bacteria, cyanobacteria were recognized as being blue–green algae. However, some plant scientists and modern botanists might refrain or disagree to classify cyanobacteria as plants or algae (Reynolds 1984). They can be found in any terrestrial and aquatic habitat. As cyanobacteria are photosynthetic, they also produce oxygen. However, some species can repair atmospheric nitrogen through cells named heterocysts in anaerobic conditions (K. Kumar, Mella-Herrera, and Golden 2010; Castenholz 2015). Arthrospira platensis is one example of cyanobacteria, which is known by its common name Spirulina. For the Arthrospira genus bacteria, they come in helical coiling trichomes, with varied sizes and degrees of coiling. Arthrospira spp. has been used to make food supplements due to its high protein and lipid content, which includes other nutritional compounds such as vitamins, minerals, and photosynthetic pigments as well (Tomaselli 1997; Capelli and Cysewski 2010).
Why Microalgae?
Published in Kyoung Hee Kim, Microalgae Building Enclosures, 2022
Of over hundreds of thousands strains, biofuel researchers narrowed down the 300 most promising strains consisting mainly of green algae and diatoms.47 A promising species needs fast growth and high lipid content to make microalgae-based biofuel economical. Chlorella vulgaris and Nannochloropsis species were identified as two top lipid producers and additional species such as Haematococcus pluvialis and Chlamydomonas reinhardtii are being studied for lipid production improvement.48Chlorella sp., a freshwater green microalga, grows in a high-pH solution that provides resistance to contamination by bacteria. With up to 8% photosynthetic efficiency, Chlorella’s environmental tolerance and high lipid rates make them a good candidate for biofuel production, achieving a range of 10–48% lipid content in their biomass.49Haematococcus pluvialis, a freshwater microalgae, can reach a lipid content of up to 40% of cell dry mass.50Nannochloropsis sp. is another top candidate for algal biodiesel with 60% lipid content in their biomass.51 One of the most widely cultivated algae in the world are Spirulina (Arthrospira platensis and Arthrospira maxima). Spirulina, a blue-green freshwater microalga, is largely used as a dietary supplement in humans, agriculture, and aquaculture due to its high vitamin and nutrient content. Various studies have shown the lipid content of Spirulina to range between 5% and 19.5%, which could be used for biofuel production.52 With a combined bioethanol and methane process, Spirulina achieved an 82% starch conversion efficiency in the saccharification process to produce bioethanol, followed by an 83% efficiency during fermentation to produce methane.53Spirulina is also a more attractive option for membrane filtration than either Chlorella or Nannochloropsis, which are both circular in shape, because Spirulina’s spiral filamentous structure makes it easier to mechanically separate them from the growth culture.54
Multifaceted Utilization of Microalgal Biomass Towards Industrial Applications
Published in Prakash K. Sarangi, Latika Bhatia, Biotechnology for Waste Biomass Utilization, 2023
O. N. Tiwari, Dipankar Ghosh, Shrestha Debnath, Minakshi Sahu, Kondi Vanitha
Currently microalgal regimes represent for generating high esteem appended molecules due to their large amount of biodiversity, ability to represent reservoir of novel value-added molecules and products in all over the world. Out of 30,000 known species few are susceptible to generate different value-added products like pigments, proteins, vitamins, high amount of PUFA (Poly unsaturated fatty acid), etc. (Sharma and Sharma, 2017, Chew et al., 2017). It can adapt very well to any environment in different conditions for survive and produce different types of secondary metabolites which cannot be found in another organism. The three types of microalgae such as Dunaliella species, Chlorella species and Spirulina species mostly used to produce high value-added components (Priyadarshani and Rath, 2012; Caporgno and Mathys, 2018). D. salina, H. pluvialis, Odontella aurita, P. cruentum, Porphyridiumsp, I. galbana, P. tricornutum, L. majuscule, and Muriellopsis sp; these microalgal species are hugely used in industry for different value-added compounds production (Liu et al., 2016; Gong et al., 2011). Poly unsaturated fatty acid (PUFA) such as DHA (Docosahexaenoic acid), EPA (Eicosapentaenoic acid) has naturally derived from Schizochytrium sp., Ulkenia sp., I. galbana, C. pyrenoidosa, C. ellipsoidea and Crypthecodinium sp. microalgal species. Phaeodactylum tricornutum, Monodus subterraneus, and Nannochloropsis sp., contains (2.2–3.9% of DW), (3% of DW), and (2.8–4.3%), EPA (eicosapentaenoic acid), respectively. The universal commercial impact is ~700 million US$ per year.1.8 billion US$ in the year of 2019 has been expected global market value of algal-carotenoids (Bhalamurugan et al., 2018; Kumara et al., 2019). Lutein reaches US $309 million by 2018 market value (Andrade et al., 2018). Phycobiliproteins are used in various sectors as a high value-added molecule. It has been derived from Arthrospira platensis species having various therapeutics nutraceutical applications (Manirafasha et al., 2016). Isochrysis galbana have the highest production yield of fatty acid 10 % on dry matter (Sánchez et al., 2016). Arthrospira species contains highest proteins and high value-added molecules which are used in food industry (Varfolomeeva and Wassermanb, 2011). Lyngbya, Symploca, and Oscillatoria like different marine organism are used for building of amino acid through the combinatorial enzymatic activities including polyketide synthases (PKSs), non-ribosomal peptide synthetases (NRPSs) (Gangl et al., 2015). The unicellular green algae H. pluvialis provides high value-added red pigments up to 5% on dry weight basis (Leu and Boussiba, 2014).
Effect of nano additives in spirulina microalgae biodiesel–diesel blends in a direct injection diesel engine
Published in International Journal of Ambient Energy, 2022
The scientific name of spirulina microalgae is Arthrospira platensis. Spirulina microalgae biodiesel was prepared by the conventional transesterification process. Raw spirulina microalgae oil is sourced from Rasha petroleum products, Chennai. For the transesterification process, initially, the oil is heated from 55°C with 5 g of KOH and with methanol (250 mL) and stirred for an hour. Now the resulting solution is allowed to settle for a day and the biodiesel is found to be settled at the top with glycerin at the bottom. The biodiesel is now washed with water and the same settling process is done and the water is separated from the conical flask. B20 is a common blend because it represents a good balance of cost, emissions, cold-weather performance, materials compatibility, and the ability to act as a solvent. Most of the literature supports the B20 blend and performs better (Harish, Raju, and Subramani 2019). The presence of nanoparticles may cause engine wear on several engine components like piston, cylinder, exhaust valve and fuel injector system and also exhaust pipe corrosion issues. The main problem with the use of nanoparticles as fuel catalysts is their stability aspects (Jayaseelan et al. 2020). These nanoparticles are tending to aggregate and may chance of clogging the fuel injection system. Hence, the addition of nanoparticles must be limited in quantity. Similar research works suggested a minimum dosage level (Bala Prasad et al. 2020). Therefore, the blends used were B20 (20% spirulina microalgae biodiesel + 80% diesel fuel), B20+Zr (20% spirulina microalgae biodiesel + 80% diesel fuel + 25 ppm Zr2O3 nano additives) along with baseline diesel fuel. The properties of blending stocks were displayed in Table 1.
Protective effect of Spirulina against cyclophosphamide-induced urotoxicity in mice
Published in Egyptian Journal of Basic and Applied Sciences, 2018
Fatma M. Eltantawy, Mohamed A. Ali Sobh, Ahmed M. EL-Waseef, Rehab-Allah A. Ibrahim, Mohamed A.A. Saad
Spirulina (Sp; ArthroSpira platensis) is a photosynthetic cyanobacterium that possesses biological activity and is widely cultivated for the production of nutritional supplements [10]. Sp has also gained increasing attention from medical scientists as a nutraceutical and source of potential pharmaceuticals. Indeed, numerous active components of Sp, including phycocyanins, tocopherols, β-carotenes and phenolic compounds exhibit antioxidant properties [11]. Sp is rich in fatty acids (linoleic acid, F-linolenic acid and palmitic acid), essential amino acids, selenium (Se) and vitamins A–E [12].