Production of Cellulase by Bacillus amyloliquefaciens -ASK11 Under High Chromium Stress

Chronic exposure of soil to metal pollutants makes it imperative to study agro-ecological responses of nutrient-recycling microbiota of the soil under metal stress conditions. In this connection, we conducted a study to check the production of cellulase by a chromium-resistant and cellulose-degrading bacterial strain isolated from a leather-tanning industrial waste-contaminated area. The isolate was identified as Bacillus amyloliquefaciens -ASK11 through 16S rDNA sequencing. The supplementation of galactose and peptone as carbon and nitrogen sources, respectively enhanced the production of cellulase significantly. The bacterium yielded the production of cellulase to 20.23 U mL −1 in optimized media with 10 ppm of Cr(VI). The increments in cellulolytic activity were achieved by cultivating 10% inocula of B. amyloliquefaciens -ASK11 at pH 7 (28 °C) with aeration at 120 rpm for 96 h. Inhibitory relation between increasing chromium concentrations and the cellulolytic activity could permit the bacterium to express 1.33 U mL −1 of cellulase at 500 ppm of Cr(VI). The findings of this study suggested that chromium-resistant cellulolytic bacteria could be exploited for the rehabilitation and bioremediation of chromium-ruined agro-industrial soils with concomitant gearing of carbon cycle.