“…The use of pulsation to enhance gas-liquid mass transfer has been reported previously, see for example, Baird and Garstang (1972), Baird and Rama Rao (1988), but only recently was this type of study extended to an OBC. The overall gas-liquid volumetric mass transfer coe cient, k L a, in an OBC was found to be six times higher than that in a bubble column (Hewgill et al, 1993) and 75% higher than that in a stirred tank fermenter involving a yeast culture (Ni et al, 1995).…”