Effect of glycerol on extracellular polyphenols accumulation in Lachnum DP5

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.