Compositions and methods are provided for use in controlling souring and corrosion causing prokaryotes, such as SRP, by treating oil and gas field environments or treatment fluids with a newly identified bacterial strain ATCC Accession No. PTA-124262 as a self-propagating whole cell that produces an anti-SRP bacteriocin in situ. In another aspect, the methods use one or more toxic peptides or proteins isolated therefrom in methods to control unwanted prokaryotic growth in these environments.