Isolation of Cellulolytic Bacillus subtilis Strains from Agricultural Environments

Abstract

<jats:p>The bioconversion of cellulose and hemicellulose to soluble sugars is important for global stabilization and a sustainable human society. Here, hundreds of cellulolytic bacteria were screened and isolated from soil, compost, and animal waste slurry in Jeju Island, South Korea. Among the isolates, three strains, SL9-9, C5-16, and S52-2, showing higher potential for practical uses were purified on carboxymethyl cellulose (CMC) agar plates and identified as<jats:italic>Bacillus subtilis</jats:italic>strains by morphological, physiological, and biochemical characterization and 16S rRNA gene analysis. The production patterns of cellulose or hemicellulose-degrading enzymes were investigated during cell culture. All three isolated strains produced CMCase, Avicelase,<jats:italic>β</jats:italic>-glucosidase, and xylanase enzymes, which suggested synergic cellulolytic systems in<jats:italic>Bacillus subtilis</jats:italic>. The enzymes showing CMCase, Avicelase, and xylanase activities existed in cell-free culture supernatant, meanwhile<jats:italic>β</jats:italic>-glucosidase activity was detected in cell debris suggesting that three of the enzymes, including CMCase, Avicelase, and xylanase, were extracellular, and<jats:italic>β</jats:italic>-glucosidase was cell membrane bound. The three isolates, SL9-9, C5-16, and S52-2, were not the same strains, presenting slight differences in biochemical characteristics, 16S rRNA gene sequences, and cellulolytic enzyme activities.</jats:p>

Isolation, Cellulase Activity Test and Molecular Identification of Selected Cellulolytic Bacteria Indigenous Rice Bran

“…The following are This result was also similar to some studies of rice bran isolate i.e., genus Bacillus [18,25]. Most Bacillus groups had the ability to produce cellulase enzyme, such as Bacillus subtilis [26][27], Bacillus licheniformis [6],…”

Effect of CMC and MCC as Sole Carbon Sources on Cellulase Activity and eglS Gene Expression in Three Bacillus subtilis Strains Isolated from Corn Stover

“…Notoriously, exoglucanase was also detected for all three strains at 24 h of incubation with maximum values at 96 and 120 h (Fig. 3A); the present activity data are similar to a previous report (Kim et al 2012). When MCC was used as the sole carbon source, endoglucanase activity increased after 48 h, reaching the maximum values at 96 and 120 h (Fig.…”

“…The contrasting expression levels among strains growing in CMC suggest that either eglS is not directly related to CMC degradation or that it has contrasting roles among these strains. Several authors have observed differences in cellulase activity among members of the Bacillus genus (Afzal et al 2010;Kim et al 2012). While there are no studies supporting differences in cellulase expression patterns in Bacillus, the increase in transcript levels at 24 h could have triggered the detected cellulase activities.…”

Isolation and Characterization of a Thermostable Cellulase from Bacillus licheniformis Strain Vic Isolated from Geothermal Wells in the Kenyan Rift Valley

“…The cell free supernatant from Bacillus subtilis strains SL9-9, C5-16, S52-2, and KACC10111 were found to bear CMCase and exoglucanase activities only. β-glucosidase activity was however present on the cell debris of the isolates studied [26]. Fig.…”

“…Observations that members of the Bacillus genus have a complete cellulase enzyme system have been made by [26]. The cell free supernatant from Bacillus subtilis strains SL9-9, C5-16, S52-2, and KACC10111 were found to bear CMCase and exoglucanase activities only.…”