2.4. Oxygen transfer quantification
Various models have been proposed to determine volumetric gas–liquid mass
transfer coefficient in shaking flasks. We have used the empirical equation (1) proposed
by Maier [24] and used by Seletzky et al. [25]. This correlation is valid for the
standard glass Erlenmeyer flasks and operating conditions that we have used in this
study:
kLa = 6.67 × 10−6N1,16V−0.83
L d0.38
0 d1.92 (1)
where kLa is the volumetric gas–liquid mass transfer coefficient (s−1), N the shaking
frequency (rpm), VL (mL) the working volume, d0 (cm) the shaking diameter and d
Fig. 1.