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.