Fig. 3
Growth a and glucoamylase production b profiles of the five mutants and the parental strain CBS 513.88 in shake flask fermentation. Data represent the average values and standard deviations from three replicates. Statistical significance was performed using a two-tailed Student’s t test to compare the DCW and glucoamylase activity differences between A. niger CBS 513.88 and each of the five mutants in certain time points (***p < 0.001; **p < 0.01; *p < 0.05; n.s., not significant)