Pseudohyphozyma (formerly Rhodotorula) bogoriensis synthesizes long‐chain‐length (22‐carbon chain) sophorolipids (22:0‐SL) that are variously acetylated at the 6′‐ or/and 6″‐carbons of the sophorose unit. In this paper, we describe a low‐temperature crystallization protocol that preferentially separates the 6′‐monoacetylated 22:0‐SL (6′‐Ac₁‐22:0‐SL) from a parental mixture of 22:0‐SL containing a majority (64.7%) of the 6′,6″‐diacetylated moiety (6′,6″‐Ac₂‐22:0‐SL), as deduced from high‐pressure‐liquid‐chromatography evaporative‐light‐scattering‐detection (HPLC‐ELSD) and LC/Q‐TOF‐MS analyses. Tensiometry measurements using the Wilhelmy plate method yielded minimum‐surface‐tension (SFT_min) and critical‐micelle‐concentration (CMC) values of 34.6 ± 1.0 mN m⁻¹ and 0.014 mM, respectively, for 6′‐Ac₁‐22:0‐SL (CRYSTAL) fraction and 34.9 ± 1.0 mM m⁻¹ (SFT_min) and 0.018 (CMC) for the hexane precipitate (Hx‐PRCP) fraction containing a high concentration (89.2%) of the diacetylated 6′,6″‐Ac₂‐22:0‐SL after crystal removal. In contrast, the SFT_min and CMC of the well‐studied 16‐18 carbon (C_16‐18)‐SL of Starmerella bombicola were 35–37.2 mN m⁻¹ and 0.05‐(>0.3) mM, respectively. Individually, the purified CRYSTAL and Hx‐PRCP fractions exhibited a similar degree of strong growth‐inhibition activity against Cutibacterium (formerly Propionibacterium) acnes as determined by an agar‐plate zone of inhibition assay. Study on the growth inhibition of oral health‐related bacteria, i.e., Streptococcus mutans and Lactobacillus acidophilus, showed that, depending on the bacteria and strains tested, the CRYSTAL fraction was either slightly better than or equally effective as the Hx‐PRCP fraction in inhibiting cell growth.

中文翻译：

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分离单乙酰化长链槐糖脂的低温结晶：表征其表面活性和抗菌性能

假拟假菌（原Rhodotorula）合成了长链长（22碳链）槐糖脂（22：0-SL），其在槐糖单元的6'-或/和6”-碳处被各种乙酰化。在本文中，我们描述了一种低温结晶协议优先分离6'-单乙酰化22：0-SL（6'- AC ₁从22亲代混合物：含0-SL一个：0-SL -22） 6的大部分（64.7％）'，6“-diacetylated部分（6'，6”-Ac ₂ -22：0-SL），如从高压液相色谱蒸发光散射检测推断（ HPLC-ELSD）和LC / Q-TOF-MS分析。使用Wilhelmy平板法进行的张力测量可产生最小表面张力（SFT _min）和临界胶束浓度（CMC）值，对于6'-Ac ₁ -22-22-SL（CRYSTAL）分数和34.9±1.0 mM m ^-1（34.9±1.0 mN m ^-1和0.014 mM SFT _min）和己烷析出物（Hx-PRCP）馏分的0.018（CMC），去除晶体后含有高浓度（89.2％）的二乙酰化6'，6''-Ac ₂ -22：0-SL。相比之下，经过充分研究的Starmerella bombicola的16-18碳（C _16-18） -SL的SFT _min和CMC为35-37.2 mN m ^-1和0.05-（> 0.3）mM。单独地，纯化的CRYSTAL和Hx-PRCP组分对琼脂板（以前称为丙酸杆菌）的痤疮表现出相似程度的强生长抑制活性，这是通过琼脂板抑制试验确定的。对口腔健康相关细菌（即变形链球菌和嗜酸乳杆菌）的生长抑制作用的研究表明，根据所测试的细菌和菌株，CRYSTAL组分在抑制细菌方面比Hx-PRCP组分稍好或同等有效。细胞生长。