The biomass concentration estimated by the static feedforward multiplayer neural network of 5-5-1 topology and hybrid neural network - microbe growth model with five inputs of culture time, temperature, pH and dissolved oxygen and glucose concentration. The result showed that the static feedforward multiplayer neural network mean squared error (MSE) of testing samples 1.73×10^-3. And hybrid neural network - microbe growth model offered a much better generalization accuracy than that of single neural network model, with MSE of testing samples of 0.25×10^-3, it was found that there was some deviation between estimated biomass and actual values while microbe were growing in the stationary phase.