$4-37$ A completely mixed$-$flow continuous bioreactor used for growing penicillin operates as a zero$-$order system. The input, glucose, is converted to various organic yeasts. The flow rate to this system is $20\frac{L}{m}in,$ and the conversion rate constant is $4m\frac{g}{\text{m}\text{i}\text{n}-L}.$ The influent glucose concentration is $800m\frac{g}{L},$ and the effluent must be less than $100m\frac{g}{L}.$ What is the smallest reactor capable of producing this conversion?