Biodegradation of endocrine disruptor dibutyl phthalate (DBP) by a newly isolated Methylobacillus sp. V29b and the DBP degradation pathway

Abstract

Bacteria of the genus Methylobacillus are methanotrophs, a metabolic feature that is widespread in the phylum Proteobacteria. The study demonstrates the isolation and characterization of a newly isolated Methylobacillus sp. V29b. which grows on methanol, protocatechuate, monobutyl phthalate, dibutyl phthalate, diethyl phthalate, benzyl butyl phthalate, dioctyl phthalate and diisodecyl phthalate. Methylobacillus sp. V29b was characterized with scanning electron microscopy, transmission electron microscopy, Gram staining, antibiotics sensitivity tests and biochemical characterization. It degrades 70 % of the initial DBP in minimal salt medium and 65 % of the initial DBP in samples contaminated with DBP. DBP biodegradation kinetics was explained by the Monod growth inhibition model. Values for maximum specific growth rate (µ max) and half-velocity constant (K s) are 0.07 h−1 and 998.2 mg/l, respectively. Stoichiometry for DBP degradation was calculated for Methylobacillus sp. V29b. Four metabolic intermediates, dibutyl phthalate (DBP), monobutyl phthalate, phthalic acid and pyrocatechol, were identified. Based on the metabolic intermediates identified, a chemical pathway for DBP degradation was proposed. Six genes for phthalic acid degradation were identified from the genome of Methylobacillus sp. V29b.

Mineralization of high concentrations of the endocrine disruptor dibutyl phthalate by Fusarium culmorum

“…(Hu et al 2015). Kumar and Maitra (2016) also found MBP, PA and pyrocatechol as intermediate compounds during DBP degradation by Methylobacillus sp. Metabolites of degradation of DBP (initial concentration 1000 mg/l) by Rhizobium sp.…”

“…Tang et al (2016) found that Rhizobium sp. LMB-1 had a removal capacity of nearly 100 mg of DBP/l within 60 h. Kumar and Maitra (2016) found that Methylobacillus sp. degraded 70% of DBP (initial concentration 2000 mg/l) after 192 h. Lee et al (2007) reported that the white rot fungus Polyporus brumalis nearly eliminated a concentration of 350 mg of DBP/l within 12 days and that the mycelial growth of the fungus was inhibited.…”

Characterization and application of a newly isolated pyrene-degrading bacterium, Pseudomonas monteilii

“…Recent studies have focused on bioremediation as a low-cost tool for the restoration of contaminated soil, due to its effectiveness and overall promise compared to alternative physical and chemical techniques (Shahsavari et al 2013;Zhu et al 2016). Commonly, bioremediation refers to the use of microorganisms to transform or degrade a contaminant into harmless product(s) (Antizar-Ladislao 2010; Owabor et al 2010;Kumar and Maitra 2016). Biodegradation of PAHs has attracted widespread attention, and various bacteria with the ability to degrade individual PAHs have been isolated and identified (Chen et al 2015;Zafra et al 2015).…”

Biodegradation of pyrene and benzo[a]pyrene in the liquid matrix and soil by a newly identified Raoultella planticola strain

“…The cost and efficiency are the first considerations in the implementation of remediation technologies. Bioremediation involves the utilization of microorganisms to breakdown or mineralize pollutants into less harmful or non-toxic compounds (Kumar and Maitra 2016). Its efficiency and cost-effectiveness make it a promising technology for the removal of pollutants.…”