Characterization of novel nicotine degrading bacteria, arthrobacter sp. ND1

Abstract

From activated sludge collected from sewage treatment plant (Daejon, Korea) five nicotine-degrading bacterial strains were isolated. Among them one isolate having the highest nicotine degradation activity was selected for further characterization. This strain was Gram-positive, aerobic, motile, catalase positive, oxidase positive, and blue pigment was formed from nicotine. This strain showed typical rod-coccus growth cycle. Growth occurred between 5 and 30 ℃ and optimum growth was observed at 25-30 ℃ (psychrophilic) and pH 7-8. Isolated strain ND1 had cell wall peptidoglycan type of A3α variant and the major menaquinone is MK-9($H_2$). The cell wall sugar is galactose. The predominating cellular fatty acids were terminally branched fatty acids anteiso-pentadecanoic acid (15:0 anteiso) and anteiso-heptadecanoic acid (17:0 anteiso). The G+C content of DNA was 63.6 %. The 16S rDNA-based phylogenetic analysis clearly established the strain ND1 as a member of the genus Arthrobacter. The 16S rDNA sequence of strain ND1 showed highest similarity values of 99.4% to Arthrobacter ureafaciens with the DNA-DNA relatedness levels of 82%. Due to morphological, physiological, chemotaxonomical and molecular systematical characteristics this strain was identified as new strain of Arthrobacter ureafaciens. The strain ND1 could utilize nicotine as its sole carbon and nitrogen source for the growth. Strain ND1 almost completely degraded 1.0 mM of nicotine within 48 h with growth yield of 0.105 g cell / L. 20mM of nicotine slightly inhibited cell growth and 30mM of nicotine completely inhibited cell growth and nicotine degradation. Many aromatic toxic compounds were degraded by this strain.