Characteristics Of Enzymes Involved In The Phenanthrene Degradation By Moderately Halophilic Martelella Sp. AD-3

Salicylate5-hydroxylase and dioxygenase play important parts in the polycyclic aromatic hydroxycarbons (PAHs) degradation, the researches on the two enzymes in non-halophilic microorganisms, more rarely reported in the salt-tolerant and halophilic microorganisms. for environmental remediation is not applicable especially in the high-salt environment. The reseacheres are more concerned about salicylic5-hydroxylase in the role of the single ring and bicyclic aromatic compouds degradation, the less role of research in the degradation of tricyclic aromatic ones The paper was aimed to study the characteristics of phenanthrene degradation, the activities of key enzymes in the degradation, the optimal conditions of salicylic5-hydroxylase and the sequence features of PAHs dioxygenase gene in aerobic, moderately halophilic Martelella sp. AD-3.Phenanthrene could be removed under salinities from0.5%-15%. and removed completely under salinity3%,the concentration of phenanthrene200mg/L within6days in AD-3by HPLC3. Activity analysises showed efficient activation of1-hydroxy-2-naphthoic acid hydroxylase.1-naphthol hydroxylase. salicylic5-hydroxylase involved in the degradation of phenanthrene by strain AD-3. Salicylate5-hydroxylase was found to be most active.132.8nmol/min/mg. under the concentration of phenanthrene200mg/L. salinity3%and pH9.0. A length of592bp fragment, dioxygenase gene phn592, was cloned by semi-nested polymerase chain reaction, showed95%identity to the naphthalene1.2-dioxygenase gene from halophilc Marinobacter sp. NCE312by blast.The paper showed that the salinity of growth was broad, the rate of phenanthrene degradation was high in AD-3:the activity of salicylic5-hydroxylase was found to be positive correlation with the rate of phenanthrene degradation:the molecular machanisms were different in phenanthrene degradation between strain AD-3and other non-halophilic bacterium. The study provided an important reference for further characteristics of enzymes in PAHs degradation in moderately halophilic bacterium.