2.3 Whole-cell catalysis
The G. oxydans catalyzed bioprocess for primary diols was conducted in a 250-mL Erlenmeyer flask containing 0.5 g/L MgSO4, 1 g/L KH2PO4, 2 g/L K2HPO4, 5 g/L (NH4)2SO4 and 5 g/L yeast extract. The previously washed spare cells were measured at a wavelength of 600 nm by ultraviolet spectrophotometry(Yao et al., 2017). Then, the cells with OD600 = 2 concentration were centrifuged and inoculated into the catalytic medium containing primary diols. The whole course was performed at a constant temperature of 30 ℃, with continual agitation at 220 rpm using a shaking table. Moreover, the ultra-high titer 5-HPA was conducted in a sealed oxygen supplied bioreactor (SOS-BR) in which pure oxygen (Purity≥99.9%) was fed into the bioreactor with an oxygen cylinder replacing the air compressor and the pressure of the bioreactor was controlled at 0.03-0.05 MPa by an exhaust valve(Hua et al., 2020).