The power required for agitation of non$-$aerated medium in fermentation is $\_\_\_\_\_\_\_\_$ kW$.$ Operating conditions are as follows: Fermentor diameter $=3$ m Number of impellers $=1$ Mixing speed $=300$ rpm Diameter of the Rushton turbine $=1$ m Viscosity of the broth $=0\mathrm{.}001$ Pa$.$s Density of the broth $=1000$ kg$.$m$-3$Power number $=5$