Biotechnology Letters, Vol.42, No.11, 2169-2178, 2020
Enhancement of glucaric acid production in Saccharomyces cerevisiae by expressing Vitreoscilla hemoglobin
Objective To enhance the glucaric acid (GA) production inSaccharomyces cerevisiae, theVitreoscillahemoglobin was employed to reinforce cellular oxygen supplement. Additionally, the pH-free fermentation strategy was engaged to lower the cost brought by base feeding during the acid-accumulated and long-period glucaric acid production. Results Recombinant yeast Bga-4 was constructed harboringVitreoscillahemoglobin on the basis of previous Bga-3. Higher glucose uptake rate, growth rate, and ethanol reuse rate were achieved in Bga-4 in shake-flask fermentation than those in Bga-3. Furthermore, the fed-batch fermentation in a 5-L bioreactor was performed without pH control, resulting in a final glucaric acid titer of 6.38 g/L. Conclusions Both the GA titer and biomass were enhanced along with the efficiency of ethanol re-utilization in the presence of VHb. Moreover, the absence of base feeding for long-period fermentation reduced production cost, which is meaningful for industrial applications.