Aerobic polychlorinated biphenyl-degrading bacteria isolated from the Tohoku region of Japan are not regionally endemic.

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Date: Mar. 2022
From: Canadian Journal of Microbiology(Vol. 68, Issue 3)
Publisher: NRC Research Press
Document Type: Report
Length: 6,739 words
Lexile Measure: 1400L

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Abstract :

In the Tohoku region of Japan, 72% of the land comprises mountain forest zones. During winter, severe climatic conditions include heavy snowfall. In such an environment, which is considered high in biodiversity, we assumed that aerobic bacteria would be diverse and would possess the ability to degrade polychlorinated biphenyls (PCBs). In this study, 78 environmental samples were collected from the Tohoku region and 56 aerobic PCB-degrading bacterial strains were isolated. They belonged to the genera Achromobacter, Rhodococcus, Pseudomonas, Stenotrophomonas, Comamonas, Pigmentiphaga, Xenophilus, Acinetobacter, and Pandoraea. Previously reported aerobic PCB-degrading bacterial strains isolated in Japan belonged to the same genera, except that the genera Acidovorax and Bacillus were not identified in the present study. In particular, the isolated Comamonas testosteroni strains YAZ2 and YU14-111 had high PCB-degrading abilities. Analysis of the sequences of the YAZ2 and YU14-111 strains showed that the gene structures of the bph operon, which encode enzymes associated with PCB degradation, were the same as those of the Acidovorax sp. KKS102 strain. Moreover, 2,3-biphenyl dioxygenase activity was responsible for the degradation characteristics of all the isolated strains. Overall, this study suggests that aerobic PCB-degrading bacteria are not specifically endemic to the Tohoku region but distributed across Japan. Key words: polychlorinated biphenyls, biphenyl dioxygenase, Comamonas testosteroni. Dans la region de Tohoku au Japon, 72 % du territoire est constitue de zones forestieres de montagne; en hiver, les conditions climatiques rigoureuses comprennent de fortes chutes de neige. Dans un tel environnement, considere riche en biodiversite, les auteurs ont suppose que les bacteries aerobies seraient diverses et possederaient la capacite de degrader les biphenyles polychlores (BPC). Dans cette etude, 78 echantillons environnementaux ont ete collectes dans la region de Tohoku et 56 souches bacteriennes aerobies degradant les BPC ont ete isolees. Elles appartenaient aux genres Achromobacter, Rhodococcus, Pseudomonas, Stenotrophomonas, Comamonas, Pigmentiphaga, Xenophilus, Acinetobacter et Pandoraea. Les souches bacteriennes aerobies degradant les BPC precedemment signalees et isolees au Japon appartenaient aux memes genres, a l'exception des genres Acidovorax et Bacillus qui n'ont pas ete identifies dans la presente etude. En particulier, les souches isolees YAZ2 et YU14-111 de Comamonas testosteroni avaient des capacites elevees de degradation des BPC. L'analyse des sequences des souches YAZ2 et YU14-111 montrait que les structures geniques de l'operon bph codant les enzymes associees a la degradation des BPC etaient les memes que celles de la souche Acidovorax sp. KKS102. De plus, l'activite 2,3-biphenyl dioxygenase etait responsable des caracteristiques de degradation de toutes les souches isolees. Dans l'ensemble, cette etude suggere que les bacteries aerobies degradant les BPC ne sont pas specifiquement endemiques a la region de Tohoku, mais distribuees a travers le Japon. Mots-cles : biphenyles polychlores, biphenyl dioxygenase, Comamonas testosteroni.

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Gale Document Number: GALE|A696008266