3.3. Effect of incubation period
Amylase enzyme produced by A. niger and R. stolonifer fungi increased with the length of the incubation period, with a maximum after 6 days; further incubation decreased enzyme production ( Fig. 2). Uguru et al. [49] and Gupta et al. [23] reported that the maximum production of α-amylase by A. niger was achieved after 6 and 5 days of incubation, respectively. Singh et al. [50] studied α-amylase production by Humicola lanuginosa and found maximum amylase production after 144 h of incubation. Chimata et al. [26] reported that Aspergillus MK07 produced most α-amylase after 120 h of incubation, and Erdal and Taskin [51] found maximum production of amylase by Penicillium expansum after 6 days of incubation.