TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The anaerobic conditions are created by (a1) carrying out step (a) and step (b) in the presence of one or more oxygen scavengers, (b1) degassing one or more of the raw materials, reagents, solvents and/or water used in step (a) and step (b), (c1) carrying out the step (a) and step (b) in an atmosphere comprising an inert gas or (d1) combination of (a1) and (b1), (a1) and (c1), (b1) and (c1) or (a1), (b1) and (c1). The degassing step is obtained by flushing the raw materials, reagents, solvents and water with nitrogen gas. The step (a) comprises converting DHPG with an alcohol to form a mixture comprising the corresponding DHPG ester. The step (b) results in the conversion of 7-ADCA into cephradine of at least 70% and the concentration of DHPG in the reaction mixture is below 2 wt.%. The DHPG-ester formed in the step (a) is not isolated as a solid intermediate prior to carrying out step (b). Preferred Components: The DHPGa is an amide or an ester. The alcohol is methanol (preferred) or ethanol. EXAMPLE - D-dihydrophenylglycine (153 g) was suspended in 280 ml methanol, and the suspension was degassed with nitrogen. Concentrated sulfuric acid (121 g) was dosed in 60 minutes (during the dosing the temperature was kept at 15-20 degrees C). The mixture was kept at reflux for 2 hours and concentrated at reduced pressure. Methanol (140 ml) was added and the mixture was kept again at reflux for 1 hour. The procedure was repeated for another 6 times. Finally, methanol (140 ml) was added and the solution was refluxed for another hour and cooled to ambient temperature, and worked up to give D-dihydrophenylglycine methyl ester (DHPGM) solution. Immobilized Escherichia coli PenG acylase mutant Phe-B24-Ala (37 g), 7-aminodesacetoxy-cephalosporanic acid (22.3 g), EDTA (0.03 g), sodium persulfate (0.4 g) and water (50 g) were added in a reactor, at 20 degrees C and the suspension was degassed with nitrogen. The pH was adjusted to 7.2 with 25% ammonia. The DHPGM solution (46 g) was dosed into the reactor at a constant rate in 180 minutes. The temperature was kept at 20 degrees C. After 60 minutes, solid cephradine (seed) (0.1 g) was added to the suspension. After 240 minutes, the pH was decreased to 6 with 80% sulfuric acid. The reactor was discharged and the resulting suspension was filtered to give cephradine.