Tianjin Key Laboratory of Aqua-Ecology & Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
Institute of Climate Adaptation and Marine Biotechnology (ICAMB), Universiti Malaysia Terengganu, Mengabang Telipot, Kuala Nerus, 21030, Malaysia.
World J Microbiol Biotechnol. 2024 Sep 19;40(10):325. doi: 10.1007/s11274-024-04130-8.
Euglena gracilis is a unique microalga that lacks a cell wall and is able to grow under different trophic culture conditions. In this study, cell growth, biomass production, and changes in the ultrastructure of E. gracilis cells cultivated photoautotrophically, mixotrophically, and under sequential-heterotrophy-photoinduction (SHP) were assessed. Mixotrophy induced the highest cell growth and biomass productivity (6.27 ± 0.59 mg/L/d) in E. gracilis, while the highest content of fatty acids, 2.69 ± 0.04% of dry cell weight (DCW) and amino acids, 38.16 ± 0.08% of DCW was obtained under SHP condition. E. gracilis also accumulated significantly higher saturated fatty acids and lower unsaturated fatty acids when cultivated under SHP condition. Transcriptomic analysis showed that the expression of photosynthetic genes (PsbA, PsbC, F-type ATPase alpha and beta) was lower, carbohydrate and protein synthetic genes (glnA, alg14 and fba) were expressed higher in SHP-culture cells when compared to other groups. Different trophic conditions also induced changes in the cell ultrastructure, where paramylon and starch granules were more abundant in SHP-cultured cells. The findings generated in this study illustrated that aerobic SHP cultivation of E. gracilis possesses great potential in human and animal feed applications.
衣藻是一种独特的微藻，缺乏细胞壁，能够在不同的营养培养条件下生长。本研究评估了衣藻在光自养、混合营养和顺序异养-光诱导（SHP）条件下的细胞生长、生物量生产和细胞超微结构的变化。混合营养诱导衣藻的细胞生长和生物量生产力最高（6.27±0.59mg/L/d），而在 SHP 条件下获得了最高的脂肪酸含量（占干重的 2.69±0.04%）和氨基酸含量（占干重的 38.16±0.08%）。在 SHP 条件下，衣藻还积累了显著更高的饱和脂肪酸和更低的不饱和脂肪酸。转录组分析表明，与其他组相比，SHP 培养细胞中光合基因（PsbA、PsbC、F 型 ATP 酶α和β）的表达较低，碳水化合物和蛋白质合成基因（glnA、alg14 和 fba）的表达较高。不同的营养条件也诱导了细胞超微结构的变化，其中在 SHP 培养的细胞中，副淀粉和淀粉颗粒更为丰富。本研究的结果表明，衣藻的有氧 SHP 培养在人和动物饲料应用中具有巨大的潜力。
