ition, dietary glutamate supplementation to some extent restored changed serum amino acid profile caused by mold-contaminated feed. In conclusion, glutamic acid may be act as a nutritional regulating factor to ameliorate the adverse effects induced by mycotoxins.24:T453,β-Carotene is a precursor of vitamin A and a dietary supplement for its antioxidant property. Producing β-carotene by microbial fermentation has attracted much attention owing to consumers' preference for the natural product. In this study, an engineered photosynthetic Rhodobacter sphaeroides producing β-carotene was constructed by the following strategies: (1) five promoters of different strengths were used to investigate the effect of the expression level of crtY on β-carotene content. It was found that P_rrnB increased the β-carotene content by 109%. (2) blocking of the branched pentose phosphate pathway by zwf deletion, and (3) overexpressing dxs could restore the transcriptional levels of crtE and crtB. Finally, the engineered RS-C3 has the highest β-carotene content of 14.93 mg/g dry cell weight (DCW) among all of the reported photosynthetic bacteria and the β-carotene content reached 3.34 mg/g DCW under light conditions. Our results will be available for industrial use to supply a large quantity of natural β-carotene.25:T467,The DO-stat fed-batch fermentation was carried out to explore the volumetric productivity of β-carotene in engineered Yarrowia lipolytica C11 strain. Using DO-stat fed-batch fermentation, we achieved 94 g/L biomass and 2.01 g/L β-carotene. Both biomass and β-carotene were about 1.28-fold higher than that in fed-batch fermentation. The ATP, NADP⁺/NADPH, and gene expression levels of tHMG, GGS1, carRA, and carB were promoted as compared to that in fed-batch fermentation. As for as the kinetic parameters in DO-stat fed-batch fermentation, μ_m', Y_x/s', and Y_p/s' was 0.527, 0.353, and 0.158, respectively. The μ_m' was elevated 4.66-fold than that in fed-batch fermentation. These data illustrate that more dissolved oxygen increased the biomass. The Y_x/s' and Y_p/s' were increased 1.15 and 22.57-fold, which suggest that the DO-stat fed-batch fermentation reduced the Crabtree effect and improved the utilization rate of glucose. Therefore, DO-stat fed-batch fermentation is a promising strategy in the industrialized production of β-carotene.

#	Concept	H-Index	Publications	Citations
1	Engineering	9	10	440
2	Medicine	8	8	543
3	Health Sciences	2	2	60
4	Education	1	1	42
5	Natural Sciences	1	2	44

	Year	Citations

About

Top Concepts