The thraustochytrids, the heterotrophic marine microorganisms, have received increasing attention because of their capacity for the production of high‐value products such as docosahexaenoic acid (DHA), carotenoids, and sterols. In this study, three potential Δ^5,7‐sterols, showing similar UV absorption spectra to that of ergosterol, in the thraustochytrid Schizochytrium sp. S31, were estimated by the ultraperformance liquid chromatography (UPLC) − APCI−MS/MS method. The proposed structures of three Δ^5,7‐sterols were ergosta‐5,7,24(28)‐trien‐3β‐ol, ergosta‐5,7‐dien‐3β‐ol, and 24‐ethylcholesta‐5,7,22‐trien‐3β‐ol. The contents of astaxanthin, ergosterol, and the other three Δ^5,7‐sterols in Schizochytrium sp. S31 during the cultivation performed in three separate batches were analyzed by a fast UPLC–PDA method. The results demonstrated that astaxanthin, ergosterol, and ergosta‐5,7‐dien‐3β‐ol were the predominant carotenoid and Δ^5,7‐sterols, respectively, and their contents kept increasing during the growth and reached a maximum after 23 days of cultivation. The estimated maximum contents of astaxanthin and four Δ^5,7‐sterols, including ergosterol, ergosta‐5,7‐dien‐3β‐ol, ergosta‐5,7,24(28)‐trien‐3β‐ol, and 24‐ethylcholesta‐5,7,22‐trien‐3β‐ol were 2.31, 4.02, 3.43, 0.30, and 0.97 mg g⁻¹ dry biomass, respectively. These findings are different to other strains reported in the composition and accumulation of Δ^5,7‐sterols and carotenoids. The present study suggests that Schizochytrium sp. S31 might be a promising marine microorganism for the productions of high‐value natural pigment astaxanthin, the provitamin D₂ ergosterol, and the provitamin D₄ ergosta‐5,7‐dien‐3β‐ol, and taken as a model organism to study the sterologenesis of the microorganisms because of its complexity of sterol compositions.

中文翻译：

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海洋微异养菌Schizochytrium sp中的Delta 5,7-甾醇和虾青素。S31

破囊壶菌是海洋中的异养微生物，由于它们具有生产高价值产品（如二十二碳六烯酸（DHA），类胡萝卜素和固醇）的能力而受到越来越多的关注。在这项研究中，三个可能的Δ ^5,7 -sterols，示出类似的UV吸收光谱于麦角甾醇，在破囊壶菌裂殖藻。S31是通过超高效液相色谱（UPLC）-APCI-MS / MS方法估算的。三个Δ提出的结构^5,7- -sterols是麦角甾5,7,24（28） -三烯3β醇，麦角甾-5,7-二烯3β醇，和24 ethylcholesta-5,7 22‐trien‐3β‐ol。虾青素，麦角甾醇的含量，以及其他三个Δ ^5,7在-sterols裂殖sp。通过快速UPLC-PDA方法分析了三批培养过程中的S31。结果表明，虾青素，麦角甾醇，麦角甾并-5,7-二烯3β醇是主要的类胡萝卜素和Δ ^5,7 -sterols，分别与它们的内容保持在生长过程中增加，后23天达到最大值培养。虾青素的所估计的最大内容和四个Δ ^5,7 -sterols，包括麦角甾醇，麦角甾-5,7-二烯3β醇，麦角甾5,7,24（28） -三烯3β醇，和24-乙基胆甾醇5,7,22-三烯-3β-醇分别为2.31、4.02、3.43、0.30和0.97 mg g ^-1干燥生物量。这些发现与其他菌株在^Δ5,7的组成和积累方面有所不同甾醇和类胡萝卜素。本研究表明，裂殖壶菌属。S31可能是一种有前途的海洋微生物，可用于生产高价值的天然色素虾青素，维生素原D ₂麦角固醇和维生素原D ₄麦角固醇5,7-dien-3β-醇，并被用作研究生物的模型生物由于其甾醇组合物的复杂性，微生物的甾醇生成。