The following information in the environment file must be specified:

• The molecular weights of the external metabolites are required to convert flux units [mmol/h] to [g/h].
• The feed rate and feed composition are set to zero since batch operation is simulated.
• Optimal growth rate is determined as the current value of the biomass flux. The production rate of ethanol is also updated, it is unique since it is the solution of secondary optimization problem.
• Other changes such as keeping the oxygen concentration constant can also be implemented.
• Finally, the ODEs for the bioreactor volume, the biomass and the accumulation of the external metabolites are set.

The following part of the FORTRAN code in res0.f shows the parameters of the bioreactor environment for the E. coli mono-culture simulation.

c###  Constant parameters
c     Molecular weights
      MW(1) = 0.18d0  ! [kg/mol]
      MW(2) = 0.15d0  ! [kg/mol]
      MW(3) = 0.046d0 ! [kg/mol]
      MW(4) = 1.0d0   ! [mol/mol]
c###  Specify feed properties 
      Fin  = 0.0d0 
      Fout = 0.0d0
      Xfeed(1) = 0.0d0
      Sfeed(1) = 0.0d0
      Sfeed(2) = 0.0d0
      Sfeed(3) = 0.0d0
      Sfeed(4) = 0.0d0
c###  Update growth rates and other exchange fluxes
      mu(1) = y(ny+ipar(6+np+150))
      v(3)  = y(ny+ipar(6+np+329))
c###  Update kinetics
      call updatekinetics(nlp, nextmet, nec, t, y, v)
      v(4)  = 0.0d0 ! Assume oxygen is controlled
c###  Extracellular mass balance
c     y = [Vol, X(1:nlp), S(1:nExtMet)]
c     ydot = f
c     Volume 
      f(1) = Fin - Fout
c     Microbial species
      do i=1,nlp
         f(1+i) = mu(i)*X(i) + Fin/Vol*(Xfeed(i) - X(i))
      end do
c     External metabolities
      do i=1,nextmet
         f(1+nlp+i) = MW(i)*v(i)*X(1) + Fin/Vol*(Sfeed(i) - S(i))
      end do