Abstract

The effects of several surfactants on the biosynthesis of β-1,3-D-glucan (β-glucan) and pullulan by Aureobasidium pullulans CCTCC M 2012259 were investigated, and Triton X-100 was found to decrease biomass formation but increase β-glucan and pullulan production. The addition of 5 g/L Triton X-100 to the fermentation medium and bioconversion broth significantly increased β-glucan production by 76.6% and 69.9%, respectively, when compared to the control without surfactant addition. To reveal the physiological mechanism underlying the effect of Triton X-100 on polysaccharides production, the cell morphology and viability, membrane permeability, key enzyme activities, and intracellular levels of UDPG, NADH, and ATP were determined. The results indicated that Triton X-100 increased the activities of key enzymes involved in β-glucan and pullulan biosynthesis, improved intracellular UDPG and energy supply, and accelerated the transportation rate of precursors across the cell membrane, all of which contributed to the enhanced production of β-glucan and pullulan. Moreover, a two-stage culture strategy with combined processes of batch fermentation and bioconversion was applied, and co-production of β-glucan and pullulan in the presence of 5 g/L Triton X-100 additions was further improved. The present study not only provides insights into the effect of surfactant on β-glucan and pullulan production but also presents a feasible approach for efficient production of analogue exopolysaccharides.

Key points

• Triton X-100 increased β-glucan and pullulan production under either batch fermentation or bioconversion.

• Triton X-100 increased the permeability of cell membrane and accelerated the transportation rate of precursors across cell membrane.

• Activities of key enzymes involved in β-glucan and pullulan biosynthesis were increased in the presence of Triton X-100.

• Intracellular UDPG levels and energy supply were improved by Triton X-100 addition.

中文翻译：

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Triton X-100改善了金黄担子霉菌产生β-1,3-D-葡聚糖和支链淀粉的联产

摘要

研究了几种表面活性剂对Aureobasidium pullulans CCTCC M 2012259生物合成β - 1,3 -D-葡聚糖（β-葡聚糖）和支链淀粉的影响，发现Triton X-100减少了生物量的形成，但增加了β-葡聚糖。和支链淀粉的生产。向发酵培养基和生物转化肉汤中添加5 g / L Triton X-100可显着增加β与不添加表面活性剂的对照相比，β-葡聚糖的产量分别增加了76.6％和69.9％。为了揭示潜在的Triton X-100影响多糖产生的生理机制，测定了细胞形态和活力，膜通透性，关键酶活性以及UDPG，NADH和ATP的细胞内水平。结果表明，Triton X-100增加了参与β-葡聚糖和支链淀粉生物合成的关键酶的活性，改善了细胞内UDPG和能量供应，并加快了前体穿过细胞膜的运输速度，所有这些都有助于提高产量。的β-葡聚糖和支链淀粉。此外，采用了分批发酵和生物转化相结合的两阶段培养策略，并进一步改善了在添加5 g / L Triton X-100的情况下β-葡聚糖和支链淀粉的联合生产。本研究不仅提供了对表面活性剂对β-葡聚糖和支链淀粉生产的影响的见解，而且为有效生产类似胞外多糖提供了可行的方法。

关键点

•在分批发酵或生物转化下，Triton X-100增加了β-葡聚糖和支链淀粉的产量。

• Triton X-100增加了细胞膜的通透性，并加快了前体跨细胞膜的运输速度。

•在Triton X-100的存在下，参与β-葡聚糖和支链淀粉生物合成的关键酶的活性增加。

•加入Triton X-100可改善细胞内UDPG水平和能量供应。