Effect of cell permeability and dehydrogenase expression on octane activation by CYP153A6-based whole cell Escherichia coli catalysts

Table 2 Average concentrations of active P450 over 24 h of biotransformation

Culture description	Volumetric concentration (µM)	Specific concentration (µmol_P450/g_DCW)
Low cell density (A): whole cells −GLD	1.72	0.380 ± 0.013
Low cell density (A): whole cells +GLD	0.67	0.146 ± 0.005
Low cell density (B): whole cells −GLD	1.47	0.384 ± 0.018
Low cell density (B): whole cells +GLD	0.61	0.134 ± 0.006
High cell density: whole cells −GLD	6.16 ± 0.31	0.224 ± 0.013
High cell density: whole cells +GLD	6.68 ± 0.33	0.187 ± 0.014
Rupture −GLD	4.93 ± 0.25	0.280 ± 0.068
Rupture +GLD	4.13 ± 0.28	0.238 ± 0.018
Disintegration −GLD	4.00 ± 0.13	0.247 ± 0.025
Disintegration +GLD	3.77 ± 0.13	0.240 ± 0.008
Cell free extract −GLD	3.91 ± 0.21	0.243 ± 0.018^a
Cell free extract +GLD	3.52 ± 0.13	0.219 ± 0.014^a
Acetone +GLD	5.40 ± 0.27	0.136 ± 0.009
Polymyxin B +GLD	5.98 ± 0.49	0.217 ± 0.019
Triton X-100 +GLD	5.14 ± 0.20	0.153 ± 0.004

Measurements were taken at five time points over the first 24 h of biotransformation. Two vials were sacrificed at each time point for sampling. Concentration of active P450 was determined by CO difference spectrometry in a microwell spectrophotometer using 200 μL (total) aqueous phase. The remaining aqueous phase was used to determine cell dry weight via pelleting and drying. In the case of cell free extract, specific values (marked ^a) were calculated based on the cell dry weights of the homogenised culture from which the CFE was extracted

ISSN: 1475-2859