Production, Optimization, and Characterization of an Acid Protease from a Filamentous Fungus by Solid-State Fermentation

Table 4

Effect of incubation period on acid protease production by the isolate Z1LB1.

No.	Incubation period (in hour)	PA (U/mL) mean ± SEM
1	24	—
2	48	36.8 ± 5^a
3	72	56.3 ± 7^b
4	96	88.0 ± 5.2^c
5	120	95.2 ± 7^c
6	144	71.8 ± 4.9^bc

PA: protease activity; SEM: standard error of the mean. Mean is the average of three measurements. Different letters (a, b, c) designate significantly different means as determined by the SPSS test ; temp. 30°C; initial media pH 4.5.