Tween 20对强化骆驼刺泛菌NX-11合成胞外多糖的影响

Effect of Tween 20 on enhancing extracellular polysaccharide synthesis by Pantoea alhagi NX-11

摘要:

骆驼刺泛菌NX-11胞外多糖(Pantoea alhagi NX-11 exopolysaccharides, PAPS)是一种新型微生物源生物刺激素，可增强农作物对盐和干旱胁迫的抗性，且生物可降解，在农业提产增效领域具有巨大应用前景。但其高黏发酵特征体系造成的发酵过程传氧效率低下，严重制约产量提升和下游处理。本研究分析了Span 80、Span 20、Tween 80、Tween 20、甘油、橄榄油和大豆油等7种氧载体对发酵产量的影响。结果表明：添加0.5% (体积分数) Tween 20促进PAPS生产效果最佳。扩大培养中，在7.5 L生物反应器添加0.5% (体积分数) Tween 20后，PAPS产量达(16.85±0.50) g/L，比对照组提高了17.70%。此外，多糖流变学表征和多糖产品微观结构结果显示，氧载体处理组多糖的特征结构未发生改变但其黏度增加。本研究结果为进一步提高其他高分子产品的生物合成效率提供了一定的借鉴。

Abstract:

Pantoea alhagi NX-11 exopolysaccharide (PAPS) is a novel microbial biostimulant that enhances crop resistance to salt and drought stress. It is biodegradable and holds promising applications in improving agricultural yield and efficiency. However, the fermentation process of PAPS exhibits a high viscosity due to low oxygen transfer efficiency, which hinders yield improvement and downstream processing. This study aimed to investigate the effects of seven oxygen carriers (Span 80, Span 20, Tween 80, Tween 20, glycerin, olive oil, and soybean oil) on fermentation yield. The results showed that the addition of 0.5% (V/V) Tween 20 significantly enhanced the production of PAPS. Moreover, the introduction of 0.5% (V/V) Tween 20 in a 7.5 L fermenter resulted in a PAPS titer of (16.85±0.50) g/L, which was 17.70% higher than that of the control group. Furthermore, the rheological characterization and the microstructure analysis of the polysaccharide products revealed that the characteristic structure of polysaccharides remained unchanged in the oxygen carrier treated group, but their viscosity increased. These findings may facilitate enhancing the biosynthesis efficiency of other polymer products