Enhancing beta-carotene biosynthesis and gene transcriptional regulation in Blakeslea trispora with sodium acetate

Abstract

The mold Blakeslea trispora is one of the most promising and economically attractive natural sources of β-carotene. In this study, the effects of sodium acetate (NaAC) on β-carotene content and production in mated B. trispora were investigated. The results show that the addition of acetate into mated medium could enhance β-carotene accumulation in B. trispora. The highest β-carotene content (59.91mg/g dry biomass) and production (2130mg/l) were obtained as adding 35mM of NaAC at stationary phase, which were 77.7% and 80.5% increments compared with that of the control, respectively. Furthermore, the effects of NaAC on expression levels of carotenogenesis genes in mated B. trispora were investigated. The results show that addition of NaAC in mated medium caused the induction of five carotenogenesis genes expression (hmgR, carG, ipi, carRA, and carB) and promoted de novo synthesis of β-carotene. The induction of five genes expression exhibited sequential gene expression profiles and the five gene expression were ranging from 1.8 to 3.8 folds increment as early as 24h after NaAC addition. We demonstrate that NaAC stimulation of β-carotene biosynthesis in mated B. trispora involved in change at genes transcriptional levels. Such regulatory mechanism provides an explanation for effect of NaAC on the biosynthesis of β-carotene in mated B. trispora.