Assays for cellulolytic enzymes
Cellulase assay for the selected EDB was performed on modified
nitrogen free agar (Döbereiner et al. 1972) supplemented
with 0.25% (w/v) carboxymethyl cellulose instead of glucose
and 0.5 % (w/v) tryptone (Verma et al. 2001). The bacteria
were spotted on the agar plate and incubated at 30 °C for 48 h,
then soaked with Congo red solution for 1 min and then rinsed
with 1 M NaCl solution (Reinhold-Hurek et al. 1993). The
screening for pectinase production was tested by spotting
bacteria on the same nitrogen free agar that was supplemented
with 0.5 % (w/v) tryptone and 0.5 % (w/v) citrus pectin
instead of glucose. The culture plates were incubated at
30 °C for 48, then soaked with 2 % (w/v) hexadecyltrimethyl
ammonium bromide (CTAB) solution for 30 min, and rinsed
with 1 M NaCl solution to visualize the halo zone around the
bacterial colonies (Mateos et al. 1992). Chitinase assay was
carried out by spotting test of the bacteria onto chitin agar (Hsu
and Lockwood 1975), while colloidal chitin component was
Ann Microbiol (2015) 65:253–266 255
prepared following the protocol described by Chaiharn and
Lumyong (2009). The culture plates were incubated at 30 °C
for 72 h, and the presence of clear zone around inoculated
colonies indicated positive chitinase activity.