Density-dependent enhancement of methane oxidation activity and growth of Methylocystis sp. by a non-methanotrophic bacterium Sphingopyxis sp.

So Yeon Jeong, Kyung Suk Cho, Tae Gwan Kim

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18 Scopus citations


Methanotrophs are a biological resource as they degrade the greenhouse gas methane and various organic contaminants. Several non-methanotrophic bacteria have shown potential to stimulate growth of methanotrophs when co-cultured, and however, the ecology is largely unknown. Effects of Sphingopyxis sp. NM1 on methanotrophic activity and growth of Methylocystis sp. M6 were investigated in this study. M6 and NM1 were mixed at mixing ratios of 9:1,1:1, and 1:9 (v/v), using cell suspensions of 7.5 7times; 1011 cells L1. Methane oxidation of M6 was monitored, and M6 population was estimated using fluorescence in situ hybridization (FISH). Real-time PCR was applied to quantify rRNA and expression of transcripts for three enzymes involved in the methane oxidation pathway. NM1 had a positive effect on M6 growth at a 1:9 ratio (p<0.05), while no significant effects were observed at 9:1 and 1:1 ratios. NM1 enhanced the methane oxidation 1.34-fold at the 1:9 ratio. NM1 increased the population density and relative rRNA level of M6 by 2.4-fold and 5.4-fold at the 1:9 ratio, indicating that NM1 stimulated the population growth of M6. NM1 increased the relative transcriptional expression of all mRNA targets only at the 1:9 ratio. These results demonstrated that NM1 enhanced the methanotrophic activity and growth of M6, which was dependent on the proportion of NM1 present in the culture. This stimulation can be used as management and enhancement strategies for methanotrophic biotechnological processes.

Original languageEnglish
Pages (from-to)128-133
Number of pages6
JournalBiotechnology Reports
Issue number1
StatePublished - 1 Dec 2014

Bibliographical note

Funding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science ( 2012R1A2A2A03046724 ) and by the Ministry of Education ( 2013R1A1A2061015 ).

Publisher Copyright:
© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (


  • Methanotrophic activity
  • Methylocystis
  • Microbial interaction
  • Population growth
  • Sphingopyxis


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