Functional Polysaccharides Research Group, Instituto de Ciencias Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Sede Talca, Talca, Chile.
Facultad de Ciencias para el Cuidado de la Salud, Universidad San Sebastián, Campus Las Tres Pascualas, Lientur 1457, 4080871, Concepción, Chile.
Sci Rep. 2024 Oct 23;14(1):25058. doi: 10.1038/s41598-024-74830-6.
Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermotolerant (growth from 34-44 °C) strain Pseudomonas alcaligenes Med1 from Medano hot spring (39.1 °C surface temperature, pH 7.1) located in the Central Andean Mountains of Chile. Bacterial growth was screened for temperature tolerance (10-60 °C) to confirm the thermotolerance behaviour. Physicochemical properties of the EPS were characterized by different techniques: Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). Whole genome of P. alcaligenes Med1 has also been studied in detail to correlate the structural and functional characteristics with genomic insight. The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps composed of mainly carbon and oxygen. The monosaccharide analysis has shown the presence of glucose, galactose, and mannose sugars at different ratios. TGA revealed the high thermal stability (315.3 °C) of the polysaccharide. The GPC has shown that Med1 is a low molecular weight polysaccharide (34.8 kDa) with low PI. The 2D-NMR linkage analysis suggests a diverse array of glycosidic bonds within the exopolysaccharide structure. The functional properties of the EPS were evaluated for food industry applications, specifically for antioxidant (DPPH, FRAP an HO). Extracted Med1 EPS revealed significant emulsification activity against different food grade vegetative oils (Coconut oil, Corn oil, Canola oil, Avocado oil, Sunflower oil, Olive oil, and Sesame oil). The highest 33.9% flocculation activity was observed with 60 mg L EPS concentration. It showed water-holding (WHC) of 107.6% and oil-holding (OHC) capacity of 110.8%. The functional EPS produced by Pseudomonas alcaligenes Med1 from Central Andean Chilean hot spring of central Chile can be a useful additive for the food-processing industry.
胞外多糖 (EPSs) 是细菌生物膜的组成部分，作为极端微生物的保护鞘，具有很高的工业价值。在这项研究中，我们阐明了一种来自嗜热菌 (生长温度为 34-44°C) 假单胞菌的新型 EPS，该菌来自智利中央安第斯山脉的梅达诺温泉 (表面温度为 39.1°C，pH 值为 7.1)。通过筛选细菌的耐温性 (10-60°C) 来确认其耐温行为。通过不同的技术对 EPS 的物理化学性质进行了表征：扫描电子显微镜-能量色散 X 射线光谱 (SEM-EDS)、原子力显微镜 (AFM)、高效液相色谱 (HPLC)、凝胶渗透色谱 (GPC)、傅里叶变换红外光谱 (FTIR)、核磁共振 (NMR) 和热重分析 (TGA)。还详细研究了 P. alcaligenes Med1 的全基因组，以将结构和功能特征与基因组洞察力相关联。EPS 表现出无定形的表面粗糙度，由主要由碳和氧组成的均匀分布的大分子块组成。单糖分析表明，葡萄糖、半乳糖和甘露糖的比例不同。TGA 显示多糖具有很高的热稳定性 (315.3°C)。GPC 表明 Med1 是一种低分子量多糖 (34.8 kDa)，PI 较低。二维 NMR 键合分析表明，在 EPS 结构中存在多种糖苷键。评估了 EPS 的功能特性，以用于食品工业应用，特别是抗氧化剂 (DPPH、FRAP 和 HO)。从智利中部安第斯山脉的温泉中提取的 Med1 EPS 表现出对不同食品级植物油 (椰子油、玉米油、菜籽油、鳄梨油、葵花籽油、橄榄油和芝麻油) 的显著乳化活性。在 60 mg L EPS 浓度下观察到最高 33.9%的絮凝活性。它显示出 107.6%的持水能力 (WHC) 和 110.8%的持油能力 (OHC)。智利中部安第斯山脉温泉中分离的假单胞菌产生的功能性 EPS 可作为食品加工业的有用添加剂。
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