title: Inhibition of microbial growth and metabolism by excess turbulence.
abstract: Excess turbulence caused by high-intensity stirring inhibited microbial growth and metabolism. In stirred tank bioreactors, the growth rate and lysine biosynthesis decreased in Brevibacterium flavum beyond 900 rpm, the growth rate of Trichoderma reesei on wheat straw beyond 150 rpm, and the growth rate of Saccharomyces cerevisae beyond 800 rpm. The term turbohypobiosis was introduced to describe this inhibition. Turbohypobiosis was characterized by a stress factor F(str) expressing the interaction of medium flow with microbial cells in local turbulent zones, dependent on the energy distribution of the stirring regime. Lysine synthesis was inhibited at significantly lower F(str) values than the growth of B. flavum. The main reason for the inhibition was shear effects causing decreased adenosine triphosphate (ATP) generation, lower O(2) uptake, and lower specific growth rate of bacteria.
authors.affiliation: August Kirchenstein Institute of Microbiology, Latvian Academy of Sciences, 226067 Riga, Kleisti, Latvian Republic, USSR.
authors.forename: M K
authors.initials: MK
authors.lastname: Toma
authors.forename: M P
authors.initials: MP
authors.lastname: Ruklisha
authors.forename: J J
authors.initials: JJ
authors.lastname: Vanags
authors.forename: M O
authors.initials: MO
authors.lastname: Zeltina
authors.forename: M P
authors.initials: MP
authors.lastname: Lelte
authors.forename: N I
authors.initials: NI
authors.lastname: Galinine
authors.forename: U E
authors.initials: UE
authors.lastname: Viesturs
authors.forename: R P
authors.initials: RP
authors.lastname: Tengerdy