Physiological, biochemical, and genetic characterization of an alicyclic amine-degrading Mycobacterium sp. strain THO100
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O RI G I NAL PAPE R
Physiological, biochemical, and genetic characterization of an alicyclic amine-degrading Mycobacterium sp. strain THO100 isolated from a morpholine-containing culture of activated sewage sludge Yong-Hak Kim · Ilnam Kang · Hélène Bergeron · Peter C. K. Lau · Karl-Heinrich Engesser · Sang-Jong Kim
Received: 23 February 2006 / Revised: 2 June 2006 / Accepted: 21 July 2006 / Published online: 16 August 2006 © Springer-Verlag 2006
Abstract Mycobacterium sp. strain THO100 was isolated from a morpholine-containing culture of activated sewage sludge. This strain was able to utilize pyrrolidine, morpholine, piperidine, piperazine, and 1,2,3,6-tetrahydropyridine as the sole sources of carbon, nitrogen, and energy. The degradation pathway of pyrrolidine as the best substrate for cellular growth was proposed based on the assays of substrate-induced cytochrome P450 and constitutive enzyme activities toward 4-aminobutyric acid (GABA) and succinic semialdehyde (SSA). Its 16S ribosomal RNA gene sequence (16S rDNA) was identical to that of Mycobacterium tokaiense ATCC 27282T. The morABC genes responsible for alicyclic amine degradation were nearly identical among diVerent species of Mycobacteria. Remarkably, repetitive sequences at the intergenic spacer (IGS) region between morC and orf1’ were detected by comparison of the nearly identical mor gene cluster regions. Considering the strain activity for alicyclic amine degradation, the deleted 65-bp DNA
Y.-H. Kim · I. Kang · S.-J. Kim (&) School of Biological Sciences, Seoul National University, San 56-1 Shinrim, Kwanak, Seoul, Republic of Korea e-mail: [email protected] H. Bergeron · P. C. K. Lau Bioconversion and Sustainable Development, Biotechnology Research Institute, NRC Canada, 6100 Royalmount Avenue, H4P 2R2 Montreal, QC, Canada K.-H. Engesser Abteilung Biologische Abluftreinigung, ISWA, Universität Stuttgart, Bandtäle 2, Stuttgart, Germany
segment did not signiWcantly alter the open reading frames, and the expression and functions of the P450mor system remained unaltered. In addition, we found a spontaneous deletion of P450mor from another strain HE5 containing the archetypal mor gene cluster, which indicated a possible occurrence of DNA recombination to rearrange the DNA. Keywords Alicyclic amines (AA) · Cytochrome P450 monooxygenase (P450) · DNA deletion · Mycobacterium · Phylogeny
Introduction Alicyclic amines (AAs), known as N-heterocyclic alkanes, are frequently detected in the environment; further, the N-heterocycle content per cigarette is approximately 80–400 g (IARC 1986). Because of their large-scale use in solvents, additives, anticorrosive agents, synthetic drugs, agricultural chemicals, pH regulators, and dyes, signiWcant amounts of AAs are released into the air, drinking water, food and are incorporated into human tissues, thereby becoming emerging issues related to environmental safety and human health (Levallois et al. 2000). The chemical and biological nitrosation of N-heterocycles increases the mutagenicity in Salmonella typhimurium t
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