Kim Jee Young, Oh Jeong-Joo, Kim Da Hee, Kim Hyun Soo, Lee Changsu, Park Jaewon, Choi Yoon-E
Division of Environmental Science & Ecological Engineering, Korea University, Seoul, 02841, South Korea.
Korea Institute of Machinery and Materials, Daegu Research Center for Medical Devices and Rehabilitation, Daegu, 42994, South Korea.
Appl Microbiol Biotechnol. 2021 Feb;105(3):1031-1039. doi: 10.1007/s00253-020-11033-9. Epub 2021 Jan 7.
Paramylon also called β-1,3-glucan is a value-added product produced from Euglena gracilis. Recently, researchers have developed various strategies for the enhanced paramylon production, among which electrical treatment for microbial stimulation can be an alternative owing to the applicability to large-scale cultivation. In this study, we applied the electrical treatment for enhanced paramylon production and found the proper treatment conditions. Under the treatment with platinum electrodes at 10 mA, the paramylon production of treated cells was significantly increased about 2.5-fold, compared to those of the untreated cells, although the density of cells was maintained due to considerable stress. The size of treated cells became larger, possibly due to the increased level of paramylon production within the cells. Accordingly, the contents of glucose uptake, glucose-6-phosphate (G6P), glucose-1-phosphate (G1P), and uridine diphosphoglucose (UDPG) were shifted to appropriate states for the process of paramylon synthesis under the treatment. The increased level of transcripts encoding glucan synthase-like 2 (EgGSL2) was also confirmed via droplet digital PCR (ddPCR) under the treatment. Overall, this study makes a major contribution to research on electrical stimulation and provides new insights into E. gracilis metabolism like paramylon synthesis. KEY POINTS: • Electrical treatment induced the paramylon production and morphological change of Euglena gracilis. • The glucose uptake of E. gracilis was increased during the electrical treatment, fueling the paramylon synthesis.
副淀粉也称为β-1,3-葡聚糖，是一种由纤细裸藻生产的增值产品。最近，研究人员开发了各种提高副淀粉产量的策略，其中由于适用于大规模培养，微生物刺激的电处理可以成为一种替代方法。在本研究中，我们应用电处理来提高副淀粉产量并找到了合适的处理条件。在用铂电极以10 mA进行处理的情况下，与未处理的细胞相比，处理后细胞的副淀粉产量显著增加了约2.5倍，尽管由于相当大的压力细胞密度得以维持。处理后细胞的尺寸变大，这可能是由于细胞内副淀粉产量增加所致。因此，在处理下，葡萄糖摄取、6-磷酸葡萄糖（G6P）、1-磷酸葡萄糖（G1P）和尿苷二磷酸葡萄糖（UDPG）的含量转移到了适合副淀粉合成过程的状态。在处理下，还通过液滴数字PCR（ddPCR）证实了编码类葡聚糖合酶2（EgGSL2）的转录本水平增加。总体而言，本研究对电刺激研究做出了重大贡献，并为纤细裸藻的代谢如副淀粉合成提供了新的见解。关键点：• 电处理诱导了纤细裸藻的副淀粉产量和形态变化。• 在电处理期间，纤细裸藻的葡萄糖摄取增加，为副淀粉合成提供了燃料。
