title: Inhibitory effect of acetic acid on growth of hyperthermophilic archaeon Pyrococcus furiosus.
abstract: The growth inhibition of Pyrococcus furiosus by acetic acid was stronger than that by hydrogen and could be described by a non-competitive inhibition model in which the inhibition constants of undissociated acetic acid, K(p) and n, were estimated to be 0.69 mM (25 mM total acetic acid at pH 6.5; pKa=4.96; 98 degrees C) and 1.0, respectively. In order to reduce the acetic acid inhibition, repeated-batch culturing was performed using a filtration module. This yielded 0.49 g of dry cells l(-1) after growth for 12 h after inoculation. It became impossible, however, to continue repeated-batch culturing manually because the time intervals for medium replacement became too short. In order to automatically maintain a low concentration of acetic acid, a perfusion culture was carried out in which medium feeding coupled to a pH-auxostat was performed. In this perfusion culture, it was possible to maintain the acetic acid concentration below 7.6 mM during exponential growth of P. furiosus, resulting in 1.8 g of dry cells l(-1) at 15 h after inoculation.
authors.affiliation: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739-8527, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakashimada
authors.forename: K
authors.initials: K
authors.lastname: Nakae
authors.forename: N
authors.initials: N
authors.lastname: Nishio