Caccamo Maria Teresa, Zammuto Vincenzo, Spanò Antonio, Gugliandolo Concetta, Magazù Salvatore
Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres 31, 98166 Messina, Italy.
Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D'Alcontres 31, 98166 Messina, Italy.
Materials (Basel). 2022 Aug 30;15(17):5988. doi: 10.3390/ma15175988.
The surfactin-like lipopeptide (BS-SBP3) and the exopolysaccharide (EPS-SBP3) produced by the polyextremophilic SBP3 (DSM 103063) have been recently described as valuable biopolymers useful in biotechnological applications. To investigate the hydrating capabilities of BS-SBP3 and EPS-SBP3, here we evaluated (i) their wetting properties, measuring the contact angle; (ii) their moisture uptake abilities using the gravimetric method; and (iii) their hydrating states (from 0 to 160% / of water content) using ATR-FTIR spectroscopy. BS-SBP3 reduced the water contact angle on a hydrophobic surface from 81.7° to 51.3°, whereas the contact angle in the presence of EPS-SBP3 was 72.9°, indicating that BS-SBP3 improved the wettability of the hydrophobic surface. In the moisture uptake tests, EPS-SBP3 absorbed more water than BS-SBP3, increasing its weight from 10 mg to 30.1 mg after 36 h of 100% humidity exposure. Spectral distance and cross-correlation analyses were used to evaluate the molecular changes of the two biopolymers during the hydration process. As the water concentration increased, BS-SBP3 spectra changed in intensity in the two contributions of the OH-stretching band named "closed" and "open" (3247 and 3336 cm, respectively). Differently, the spectra of EPS-SBP3 exhibited a broader peak (3257 cm), which shifted at higher water concentrations. As evaluated by the spectral distance and the wavelet cross-correlation analysis, the OH-stretching bands of the BS-SBP3 and EPS-SBP3 changed as a function of water content, with two different sigmoidal trends having the inflection points at 80% and 48%, respectively, indicating peculiar water-properties of each biopolymer. As wetting agents, these biopolymers might replace industrially manufactured additives in agriculture and the food and cosmetic industries.
多极端嗜性菌株SBP3（DSM 103063）产生的类表面活性素脂肽（BS-SBP3）和胞外多糖（EPS-SBP3）最近被描述为在生物技术应用中有用的有价值生物聚合物。为了研究BS-SBP3和EPS-SBP3的保湿能力，我们在此评估了：（i）它们的润湿性能，通过测量接触角；（ii）使用重量法测定它们的吸湿能力；以及（iii）使用衰减全反射傅里叶变换红外光谱（ATR-FTIR光谱）测定它们的水合状态（含水量从0至160%）。BS-SBP3将疏水表面上的水接触角从81.7°降低至51.3°，而在存在EPS-SBP3的情况下接触角为72.9°，这表明BS-SBP3改善了疏水表面的润湿性。在吸湿试验中，EPS-SBP3比BS-SBP3吸收了更多的水，在100%湿度暴露36小时后其重量从10毫克增加到30.1毫克。光谱距离和互相关分析用于评估两种生物聚合物在水合过程中的分子变化。随着水浓度增加，BS-SBP3光谱在名为“封闭”和“开放”的OH伸缩带的两个贡献（分别为3247和3336厘米）中的强度发生变化。不同的是，EPS-SBP3的光谱表现出一个更宽的峰（3257厘米），该峰在更高水浓度下发生位移。通过光谱距离和小波互相关分析评估，BS-SBP3和EPS-SBP3的OH伸缩带随含水量而变化，具有两种不同的S形趋势，其拐点分别在80%和48%，这表明每种生物聚合物具有独特的水性质。作为润湿剂，这些生物聚合物可能会取代农业以及食品和化妆品行业中工业生产的添加剂。
