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Biomolecules from Microalgae for Commercial Applications
Published in Kalyan Gayen, Tridib Kumar Bhowmick, Sunil K. Maity, Sustainable Downstream Processing of Microalgae for Industrial Application, 2019
Meghna Rajvanshi, Uma Shankar Sagaram, G. Venkata Subhash, G. Raja Krishna Kumar, Chitranshu Kumar, Sridharan Govindachary, Santanu Dasgupta
Astaxanthin (3,3'-dihydroxy-b, b-carotene-4,4'-dione) is produced by some micro- and macro-green algae, plants, fungi and bacteria. In microalgae, Haematococcus pluvialis, Neochloris wimmeri, Chlorella zofingiensis, Chlorococcum sp., Protosiphon botryoides, Scotiellopsis oocystiformis and Scenedesmus vacuolatus are reported to produce astaxanthin (Orosa et al. 2001). Among all of these, H. pluvialis is considered a commercially viable strain because it can accumulate up to about 5% of dry weight as astaxanthin. The anti-oxidant property of astaxanthin, which is commonly represented by oxygen radical absorbance capacity (ORAC) (2,822,200 μ mol TE/100 G), is a great deal higher than the ORAC of vitamin E and vitamin C (Superfoodly 2018). Further, the anti-cancer, anti-inflammatory, anti-diabetic, photoprotective, skin damage protection and DNA repair properties of astaxanthin have increased the demand in global pharmaceutical and nutraceutical industries. Commercially, astaxanthin is currently produced from H. pluvialis, yeast fermentation and chemical synthesis. Natural astaxanthin derived from H. pluvialis is esterified (>95%) and ideal for human applications like dietary supplements, cosmetics and food. Yeast accumulates ~0.5% astaxanthin by dry weight. Chemically, astaxanthin is mainly synthesized by the reaction of C15 phosphonium salts with C10 dialdehyde (Wittig reaction), or by hydroxylation of canthaxanthin, or by oxidation of zeaxanthin. Chemically synthesized astaxanthin is an unesterified or free form with low ORAC, and hence suspected to be less effective. However, chemically synthesized astaxanthin dominates the global market due to the lower cost of synthesis (Nguyen 2013). Astaxanthin is widely used as a food colorant and in aqua culture to feed salmon and crustaceans like shrimp, crab, lobster and krill (Miyashita and Hosokawa 2019). Global astaxanthin production was USD 615 million in 2016. Astaxanthin—Global Market Outlook (2017–2023) estimates that world astaxanthin production will be USD 1226 million in 2023, with a CAGR of 10.3% because of increasing demand in cosmetics, nutraceuticals and health care products (Wood 2017). Demand for natural astaxanthin derived from H. pluvialis was ~55% in 2017 by the global nutraceutical market, and it is predicted to be 190 Metric Ton by 2024 (Wood 2018). The FDA has granted GRAS status to astaxanthin extracted from H. pluvialis by the supercritical CO2 method and advised a permissible human consumption dosage up to 12 mg/day to 24 mg/day for a maximum of 30 days (Davinelli, Nielsen, and Scapagnini 2018). Market analysts opined that natural astaxanthin market (USD 7000/kg) growth can go higher because of expanding end-use applications. However, the labor-intensive cultivation and production processes of natural astaxanthin and adulteration with cheap, chemically synthesized (USD 2000/kg) or yeast-fermented astaxanthin (USD 2500/kg) are major obstacles in the sustained growth of the natural astaxanthin market (Nguyen 2013).
Improvement of oxidation stability of biodiesel by an antioxidant component contained in spent coffee grounds
Published in Biofuels, 2021
Masatoshi Todaka, Wasana Kowhakul, Hiroshi Masamoto, Mikiji Shigematsu
As an antioxidant evaluation method, oxygen radical absorbance capacity (ORAC) is attractive because this method can measure the antioxidant capacity of both hydrophilic and hydrophobic fractions, such as vegetable oils and plant material. Kraujalienė et al. reported the hexane extraction fraction from plant materials evaluated using the ORAC method [21]. Also, Marineli et al. used the ORAC method for antioxidant evaluation; they measured the antioxidant of chia seed oil as the hydrophobic and chia seed methanol extract as the hydrophilic fraction [22]. In the antioxidant evaluation of coffee using the ORAC method, Yashin et al. reported the effect of different roasted conditions on the antioxidant capacity of coffee bean [23]. In this way, the ORAC method is suitable for antioxidant measurement because it can evaluate both hydrophilic and hydrophobic materials.