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Involvement of laccase-like enzymes in humic substance degradation by diverse polar soil bacteria

Cited 3 time in wos
Cited 3 time in scopus
Involvement of laccase-like enzymes in humic substance degradation by diverse polar soil bacteria
Other Titles
극지토양 미생물에 의한 부식질 분해과정에서 Laccase 효소의 역할 규명
Park, Ha Ju
Lee, Yung Mi
Do, Hackwon
Lee, Jun Hyuck
Kim, Eungbin
Lee, Hyoungseok
Kim, Dockyu
Biotechnology & Applied MicrobiologyMicrobiology
BiodegradationCold-adaptedHumic acidsLaccasePolarSoil bacteria
Issue Date
Park, Ha Ju, et al. 2021. "Involvement of laccase-like enzymes in humic substance degradation by diverse polar soil bacteria". FOLIA MICROBIOLOGICA, 66(3): 331-340.
Humic substances (HS) in soil are widely distributed in cold environments and account for a significant fraction of soil's organic carbon. Bacterial strains (n = 281) were isolated at 15 degrees C using medium containing humic acids (HA), a principal component of HS, from a variety of polar soil samples: 217 from the Antarctic and 64 from the Arctic. We identified 73 potential HA-degrading bacteria based on 16S rRNA sequence similarity, and these sequences were affiliated with phyla Proteobacteria (73.9%), Actinobacteria (20.5%), and Bacteroidetes (5.5%). HA-degrading strains were further classified into the genera Pseudomonas (51 strains), Rhodococcus (10 strains), or others (12 strains). Most strains degraded HA between 10 and 25 degrees C, but not above 30 degrees C, indicating cold-adapted degradation. Thirty unique laccase-like multicopper oxidase (LMCO) gene fragments were PCR-amplified from 71% of the 73 HA-degrading bacterial strains, all of which included conserved copper-binding regions (CBR) I and II, both essential for laccase activity. Bacterial LMCO sequences differed from known fungal laccases; for example, a cysteine residue between CBR I and CBR II in fungal laccases was not detected in bacterial LMCOs. This suggests a bacterial biomarker role for LMCO to predict changes in HS-degradation rates in tundra regions as global climate changes. Computer-aided molecular modeling showed these LMCOs contain a highly-conserved copper-dependent active site formed by three histidine residues between CBR I and CBR II. Phylogenetic- and modeling-based methods confirmed the wide occurrence of LMCO genes in HA-degrading polar soil bacteria and linked their putative gene functions with initial HS-degradation processes.
King Sejong Station
Appears in Collections  
2020-2020, Ecophysiology of KGI terrestrial organisms to reveal mechanisms of adaptation to changing environment (20-20) / Lee, Hyoungseok (PE20170)
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