The effects of various nutrients in fermentation broth on the volumetric liquid-phase mass transfer cofficient kLa were studied in a bubble column. The mathematical model for measuring kLa was modified. The correlation of kLa was derived theoretically as follows It was shown that the presence of macromolecular carbon source or nitrogen source decreased kLa

while that of urea and inorganic salts with low ion strength ( < 0.02kmol / m3) had no effect on kLa and the presence of glucose and inorganic salts with higher ion strength ( ≥0.02 kmol/m3) could increase kLa. Parameters of the correlation were determined according to the different effects of various nutrients. Values of kLa from the correlation agree well with the measured values.