As a result of isolation and screening, two strains of Bacillus sp.
(CS-1 and CS-2) were selected for alkali lignin degradation experiments
on the basis of their RBBR-decolorizing efficiency (Table 1).
With initial concentrations of 0.05–2.0 g L1, at least 61% of alkali
lignin could be degraded within 48 h (data not shown). There
was a significant biodegradation of alkali lignin (0.5 g L1) in the
culture after 24 h; the removal ratio of lignin was up to 40%, reaching
80% on the second day of incubation (Fig. 1). The maximum lignin
degradation rate of CS-1 was estimated to be 99.5% at a
concentration of 0.05 g L1 (data not shown). This result is much
better than that previously reported (Tuomela et al., 2000). The removal
percentages of lignin by CS-1 were higher than several novel
actinomycete strains, including Streptomyces spp. strains F-6 and F-
7 (Yang et al., 2012).