The current study aimed to investigate the concurrent production of astaxanthin and lipids using Chlorella sorokiniana under mixotrophic conditions in an external loop airlift photobioreactor (ELAPB). Supplementation of Fe²⁺ into the media in the red phase (stress phase) induced the astaxanthin production. The maximum yield of 154.36 mg L⁻¹ was obtained by the end of the red phase, which is equivalent to 3.4% of the dry biomass weight. The role of reactive oxygen species in the formation of astaxanthin, which protects the microalgal cells from different oxidative stress, has been elucidated. Apart from astaxanthin, unsaturated fatty acids (81.34%) were also produced with excellent biodiesel properties. Unsaturated fatty acids viz., palmitoleic acid (16:1), have resulted in high yields (22.85%), followed by linoleic acid (18:2), 28.27%; oleic acid (C18:1), 14.38%; and eicosapentaenoic acid (20:5), 4.49%. Hence, the simultaneous production of high value-added products, viz., astaxanthin, and lipids makes the whole process economically viable and environmentally sustainable and elevates the commercial potential during scale-up. The astaxanthin radical scavenging activity was also assessed by H₂O₂ assay, and the maximum scavenging activity was determined as 91%. The study confers the potential advantages of algal cultivation for high-value commercial product synthesis towards additional revenue generation and development of an efficient microalgae-based biorefinery process.

Graphical abstract

中文翻译：

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在活性氧存在下，同时从索氏小球藻同时生产虾青素和脂质：一种生物精炼方法

当前的研究旨在调查在外部营养环空运光生物反应器（ELAPB）中，在混合营养条件下使用Sorokiniana小球藻同时生产虾青素和脂质。在红色阶段（应激阶段）向培养基中补充Fe ^2+会诱导虾青素的产生。最大产量154.36 mg L ^-1到红色相结束时，获得的有机碳量相当于干生物质重量的3.4％。已经阐明了活性氧在虾青素形成中的作用，该虾青素可保护微藻细胞免受不同的氧化应激。除虾青素外，还生产出具有优异生物柴油特性的不饱和脂肪酸（81.34％）。不饱和脂肪酸，即棕榈油酸（16：1），收率高（22.85％），其次是亚油酸（18：2），收率28.27％；油酸（C18：1），14.38％; 和二十碳五烯酸（20：5），占4.49％。因此，同时生产高附加值的产品，即虾青素和脂质，使整个过程在经济上可行且在环境上可持续，并在扩大规模时提高了商业潜力。₂ O ₂分析，最大清除活性确定为91％。这项研究将藻类栽培用于高价值商业产品合成的潜在优势赋予了额外的收入来源，并开发了一种有效的基于微藻的生物精炼工艺。

图形概要