Biodegradation of Aromatic Compounds and PAHs by Halophilic Archaea

摘要

It is widely known that microorganisms have the ability to metabolize xenobiotics in the environment, and their study has received much attention due to the environmental persistence and toxicity of these compounds. Several works published in the field have concluded that a wide variety of microorganisms in pure and mixed culture under both aerobic and anaerobic conditions are capable of degrading. Among prokaryotes, haloarchaea iw known as a group with the potential for bioremediation. Geological formations, such as petrol reserves, are associated with salty environments. That is the reason why haloarchaea can be considered as a good environmental tool for bioremediation in extremely salty environments or polluted deserts. The work developed in our laboratory in the last few years has been related to the isolation of halophilic archaea, which is able to metabolize aromatic compounds. To demonstrate this, five hypersaline location were sampled-Uyuni Salt March in Bolivia, crystallizer ponds in Chile and Cabo Rojo (Puerto Rico), the sabkhas in the Persian Gulf (Saudi Arabia), and the Dead Sea (Israel and Jordan). Twelve strains able to grow on 1,2 benzoanthracene and 44 strains able to use p-hydroxybenzoic acid as the sole carbon source were isolated. After some studies were carried out with some of these isolates, we have detected activity on the degradation of some PAHs, such as of naphthalene, anthracene, fenanthrene, pyrene or 1,2-benzoanthracene, when cultivated with or without yeast extract. Some strains have also been grown on aromatic acids, giving some positive results on the degradation of p-hydroxybenoic acid. These strains were also used for preliminary biodegradation studies of hydrocarbons in produced waters showing promising results.