The enhancement of methyl tertiary butyl ether oxidation by Gordonia in the presence of nanosilver and nitrate

Introduction and objective: Several Gram-positive and Gram-negative bacteria isolated from methyl tertiary butyl ether (MTBE) reached soil. Among them one Gram-positive, oxidize positive, partial acid fast, which had strong nitrate reductase activities was identified as Gordonia. The effects of methanol, nitrate and nanosilver on MTBE removal were studied.

Materials and methods: Gordonia was isolated from MTBE enriched soil and identified by sequencing and biochemical test. The removal of MTBE was studied by Gordonia with COD Hach reagent. The production of formaldehyde and formate were determined by Hantzsch reagent and potassium permanganate, respectively. Also MTBE oxidation by nanosilver, nitrate and bacteria were compared.

Results: The results showed that the addition of 5 or 10ppm nanosilver inhibits the reaction, however 0.2ppm nanosilver increased MTBE oxidation by 15% and gives maximum 70% removal in 6h. The biodegradation of MTBE by this isolated strain only occurred when nitrate was added in media with or without Nanosilver. Also Methanol for induction or co-oxidation is necessary for MTBE oxidation by Gordonia. 

Conclusion: Gordonia has a good capacity to remove MTBE only with nitrate respiration. Therefore nitrate as electron acceptor for respiration, methanol as co-oxidation and nanosilver as catalyses in special concentration help Gordonia for MTBE removal.