function xp = teste(t,x)

   D = 0.3;
   mumax = 0.53;
   Y = 0.4;
   km = 0.12;
   sf = 4.0;
   k1 = 0.4545;
%
%  Substrate Inhibition expression for specific growth rate
%
   mu = mumax*x(2)/(km+x(2)+k1*x(2)*x(2));
%
%  dynamic equations
%
   dx1dt = (mu - D)*x(1);
   dx2dt = (sf - x(2))*D - mu*x(1)/Y;
   xp = [dx1dt; dx2dt];
