Yamane Reo, Ishida Reiya, Uejima Yuuya, Takagi Akari, Nakamura Akihiro, Asayama Munehiko
College of Agriculture, Ibaraki University, 3-21-1 Ami, Ibaraki, 300-0393, Japan.
United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8, Fuchu, Tokyo, 183-8509, Japan.
Appl Biochem Biotechnol. 2025 Jun 11. doi: 10.1007/s12010-025-05276-3.
The green alga Parachlorella sp. AMI5 is a newly identified strain that produces a substantial amount of the unique extracellular polysaccharide amiEPS. This study aimed to investigate the purification, characteristics, and function of amiEPS-N from the AMI5 strain cultivated in a nitrogen-deficient BG11 (BG11-N) culture. We successfully obtained a high yield of 1.08 g/L of purified amiEPS-N with low protein content. Characteristic analyses revealed that amiEPS-N was composed of a flexible molecular form with 0.51 ± 0.00 log (nm)/log (g/mol) of a conformation plot slope in the water solution, and the weight average molecular mass was 1.73 × 10⁶ g/mol in maximum. The monosaccharide composition of amiEPS-N was rhamnose:xylose:glucuronic acid as 55.1:34.8:10.1 (mol%), indicating that it is an acidic rhamnan. The aqueous amiEPS-N exhibited anti-angiotensin-converting enzyme and tyrosinase-enhancing activities, which may contribute to the anti-hypertensive effects and inhibition of gray hair, indicating its novel and unique properties. The biochemical characteristics of the novel amiEPS and the contribution of this production technology to the social implementation for biorefineries are discussed.
绿藻小球藻属 Parachlorella sp. AMI5 是一种新鉴定出的菌株，它能产生大量独特的细胞外多糖 amiEPS。本研究旨在探究从在缺氮 BG11（BG11-N）培养基中培养的 AMI5 菌株中纯化得到的 amiEPS-N 的纯化方法、特性及功能。我们成功获得了高产率（1.08 g/L）且蛋白质含量低的纯化 amiEPS-N。特性分析表明，amiEPS-N 在水溶液中的分子形态较为灵活，构象图斜率为 0.51 ± 0.00 log(nm)/log(g/mol)，重均分子量最大为 1.73×10⁶ g/mol。amiEPS-N 的单糖组成为鼠李糖:木糖:葡萄糖醛酸 = 55.1:34.8:10.1（摩尔%），表明它是一种酸性鼠李聚糖。amiEPS-N 水溶液具有抗血管紧张素转换酶和增强酪氨酸酶的活性，这可能有助于产生抗高血压作用和抑制白发，显示出其新颖独特的特性。本文还讨论了新型 amiEPS 的生化特性以及该生产技术对生物精炼厂社会应用的贡献。
