*2.2. Qualitative Evaluation of Enzyme Activities of Actinobacterial Strains*

There were significant differences between the 31 actinobacterial strains evaluated for their chitinolytic, cellulolytic or proteolytic activity (*p* < 0.0001) (Table 2). Twenty out of the 31 strains evaluated showed chitinolytic halo, which ranged from 25.3 ± 0.96 to 33.5 ± 1.91 mm for CBQ-CD-24 to CBQ-EBa-5, respectively. Concerning the cellulolytic activity, the cellulolytic halo ranged between 90.0 ± 0.41 (CBQ-B-8; -CB-14; -ECa-24; -ESFe-12; -Ni-32; -Plat-2; -Plat-3; -Plat-4; and -WP-14) and 36.3 ± 0.75 mm (CBQ-EA-3). Only three out of the 30 strains evaluated did not show cellulolytic halo (CBQ-EB-27; -EC-18; -OSS-4). Finally, 21 out of the 31 strains evaluated showed proteolytic halo, which ranged from 51.5 ± 1.50 to 27.0 ± 0.71 mm for CBQ-EA-12 to CBQ-ECa-24, respectively (Table 2).


**Table 2.** Chitinolytic, cellulolytic and proteolytic activity of the 31 actinobacterial strains selected for these experiments.

a,b,c Halo develop (mm) for each actinobacterial strain grown onto chitin agar medium Colloidal, Yeast Extract-Malt Extract Agar (ISP2) plates with cellulose (1%, *w*/*v*), and ISP2 agar with 1% skimmed milk, respectively, at 28–30 ◦C in darkness for seven days. For each strain, data represent the average of twelve Petri dishes ± the standard error of the means. In each column, means followed by a common letter do not differ significantly according to Dunn's multiple comparisons for proportions test at *p* = 0.05.
