pH modulates arsenic toxicity in Bacillus licheniformis DAS-2

• Arsenic [As(V) and As(III)] tolerant bacteria isolated and identified as Bacillus licheniformis DAS-2
• Arsenic [As(V) and As(III)] uptake/removal and reduction of As(V) to As(III) as a arsenic tolerance strategy.
• pH modulate arsenic toxicity.

The toxic characteristics of arsenic species, As(V) and As(III) result in ecological risks. Arsenic tolerant bacterium was isolated and identified as the Bacillus licheniformis DAS-2 through 16SrDNA sequencing. B. licheniformis DAS-2 was efficient to tolerate and remove both the As(V)[MIC 8 mM] and As(III)[MIC 6 mM] from the growth medium. The potential for the removal/uptake of arsenic from the 3, 5 and 7 mM As(V) enriched growth media was 100%, 60% and 35% respectively and from the 1, 3 and 5 mM As(III) enrichment it was 100%, 99% and 58% respectively at neutral pH. 80% of uptake As(V) was reduced to As(III) in 3 mM As(V) enrichment which was gradually decreased to only 17% at 7 mM As(V) enrichment at neutral pH. The arsenic toxicity in B. licheniformis DAS-2 was found modulated by pH and was examined through alteration in growth, uptake/removal, reduction and measurement of chemical toxicity.