3.4 Important variables
To identify the important variables, MIE were applied to the DNN models using multivalent output models (Figures 3J and 3L ).Figure 4 indicates the top 20 most important variables based on the MIE calculations. Glycerol, phosphate, glutamic acid (Glu), and trehalose or maltose indicated high average MSE in the case of both cell growth and GFP production. Several of the amino acids observed were representatives of important components. In order to examine the numerical values of the important variables, we recalculated the relationships between the number of input variables, ordered by significance, and the MSEtest each learning were indicated (Figure S3 ). The MSEtest decreased along with an increase in the number of variables and converged minimal values. The results meant that the thresholds of the importance values for cell growth and GFP were 18 and 15, respectively. According to the sensitivity analysis of the important variables, the M4 yeast extract used for a basal medium containing Glu, trehalose or maltose, isoleucine (Ile), lysine (Lys), phosphate, glycine (Gly), and aspartic acid (Asp) were predicted to increase cell yields by less than 30% (Figure S4 ). Simultaneously, Glu, glycerol, phosphate, and Lys were estimated to increase the yield of GFP (Figure S5 ). Interestingly, almost all of the important variables over the thresholds were estimated to exert a slight effect on the cell growth and GFP yields.