Abstract: Methods for monitoring, controlling, optimising and simulating a bioprocess comprising a cell culture in a bioreactor are provided. The methods comprise obtaining the values of one or more state variables of a state space model at one or more maturities, and predicting the value of one or more critical quality attributes of a product of the bioprocess using a machine learning model trained to predict the value of the one or more critical quality attributes based on input variables comprising values of the one or more state variables or variables derived therefrom, at one or more maturities. The state space model comprises a kinetic growth model representing changes in the state of the cell culture and a material balance model representing changes in the bulk concentration of one or more metabolites in the bioreactor. Systems, computer readable media implementing such methods, and methods for providing tools to implement such methods, are also provided.