Assessment of oil degrading ability in drilling mud by biosurfactant produced by some microbial strains

Abstract

Drilling mud is generated during exploratory drilling and oilfield
development, and consists of amixture ofsoil, rock contaminated with oil,
chemicals, and drilling fluid. It is very difficult and expensive to treat this
waste source, so the biosurfactant produced by microorganisms is
considered a highly effective biological treatment method. Biosurfactant
is a bipolar compound that allowsthe dissolution of insoluble substances
in water, creates an emulsion that helps microorganisms better contact
the oil and easily decompose the contaminated oil. Thisstudy was carried
out to evaluate the ability to degrade oil in drilling mud using
biosurfactant produced by some microbial strains. The results showed
thatfourmicrobialstrainsselected fromCat Ba,Hue andVung Tau areas,
namely Brevibacteria celere, Oligella ureolytica, Stenotrophomonas
maltophilia and Paenibacillus mancerans have the capacity of
decomposing oil in drilling mud. The highest emulsification index (E24) of
the four strains after 5 days culture with shaking at 200 rpm, pH = 7.5,
temperature 30°C, 1% NaCl, carbon source of saraline and DO were
recorded at 73, 71, 52 and 59%, respectively. This result shows that
biosurfactants are an active compound group with potential in oil
pollution treatment in the Petroleum industry in particular and
environmental pollution treatment in genera