A review, with refs. This contribution analyzes the position of biochem. engineering in general and bioprocess engineering particularly in the force fields between fundamental science and applications, and between academia and industry. By using culture technol. as an example, it can be shown that bioprocess engineering has moved slowly but steadily from an empirical art concerned with mainly know-how to a science elucidating the know-why of culture behavior. Highly powerful monitoring tools enable biochem. engineers to understand and explain quant. the activity of cellular culture on a metabolic basis. Among these monitoring tools are not just semi-online analyses of culture broth by HPLC, GC and FIA, but, increasingly, also noninvasive methods such as midrange IR, Raman and capacitance spectroscopy, as well as online calorimetry. The detailed and quant. insight into the metabolome and the fluxome that bioprocess engineers are establishing offers an unprecedented opportunity for building bridges between mol. biol. and engineering biosciences. Thus, one of the major tasks of biochem. engineering sciences is not developing new know-how for industrial applications, but elucidating the know-why in biochem. engineering by conducting research on the underlying scientific fundamentals. [on SciFinder (R)]