For biodegradation of alkali lignin, two most effective RBBRdecolorizing
strains (Bacillus sp. CS-1 and CS-2) were selected. Biodegradation
experiments were carried out in BSGYP (as mentioned
above) containing 0.05 g L1 of alkali lignin. Two isolates were pregrown
on BSGYP medium for 24 h. Erlenmeyer flasks (250 mL) containing
100 mL of autoclaved (20 min, 121 C) BSGYP (pH 6.0) were
inoculated with 2 mL of pregrown pure culture (0.65 mg protein
mL1) in log phase. The uninoculated (control) and bacterial
inoculated flasks were incubated at 30 C on a rotary shaker
(120 rpm) in dark conditions for 3 days. The time course of lignin
degradation was followed while shaking the flasks for 3 days. Disappearance
of alkali was monitored by aseptically removing 1 mL
samples for measurement of ultraviolet absorption spectra at
280 nm after centrifugation at 6000g for 5 min. All assays were
performed at least in duplicate with their corresponding controls.
Both non-inoculated media (blanks) and inoculated autoclaved
samples (controls) were used.