甘油对粒毛盘菌DP5胞外多酚积累的影响

Effect of glycerol on extracellular polyphenols accumulation in Lachnum DP5

摘要:

【目的】探明以甘油为碳源促进粒毛盘菌DP5积累多酚的可能原因。【方法】对碳源种类、甘油浓度、曲酸、抑制剂和前体等对多酚产量和生物量的影响进行分析。【结果】以甘油为碳源，能显著提高粒毛盘菌胞外多酚产量。甘油浓度为20 g/L时，胞外多酚产量最高，达到0.664 g GAE/L，并在发酵液中检测到曲酸，其含量为0.25 g/L。向以蔗糖为碳源的发酵液添加曲酸，胞外多酚含量从0.209 g GAE/L提高至0.376 g GAE/L。以甘油为碳源的发酵液中，酚氧化酶活性较低。粒毛盘菌DP5通过莽草酸途径和聚酮途径合成多酚，甘油有利于莽草酸途径和聚酮途径前体物质的合成。【结论】粒毛盘菌以甘油为碳源合成出曲酸，曲酸抑制多酚向黑色素的转化；甘油促进多酚前体的合成，从而提高了粒毛盘菌胞外多酚的积累量。

Abstract:

[Objective] The possible relationships between glycerol and the extracellular polyphenols (EP) production from Lachnum DP5 were explored initially. [Methods] The influences of various carbon sources, glycerol concentration, kojic acid, inhibitors and precursors on EP production and biomass were investigated. [Results] The EP accumulation was obviously increased by the addition of glycerol. The maximum EP content reached 0.664 g GAE/L when using 20 g/L glycerol as the carbon source. Meanwhile, kojic acid was produced, and its yield was 0.25 g/L. The EP yield increased from 0.209 g GAE/L to 0.376 g GAE/L by the addition of kojic acid into the sucrose-containing medium. The phenoloxidase activity was lower in the fermented glycerol-containing medium than that in the fermented sucrose-containing medium. The EP from Lachnum DP5 was biosynthesized via the shikimate and polyketide pathways. The biosynthesis of precursors of the shikimic acid and polyketide pathways were improved by glycerol. [Conclusion] Glycerol stimulated the biosynthesis of relative precursors and inhibited the bioconversion of polyphenols to melanin. Thus, EP accumulation was boosted by the addition of glycerol as carbon source.