Characterization of a methane-utilizing strain and its application for monitoring methane

Aims: To explore new resources of methane-utilizing micro-organism and develop a microbial biosensing system for monitoring methane released from natural and semi-natural ecosystems. Methods and Results: A methane (CH ₄)-utilizing bacterial strain was isolated from paddy soil using CH₄ as the sole carbon source and identified as Klebsiella sp. ME17 by phenotyping and 16S rDNA sequence analysis. The efficiency of CH₄ utilization of strain ME17 was 832% by gas chromatography analysis. A microbial biosensing system for CH₄ detection was developed by combining immobilized cells of strain ME17 with a dissolved oxygen sensor. It was found that response time of the system to CH₄ was <90s. The dissolved O₂ consumption increased with increasing CH₄ from 0% to 160% (v/v) demonstrating a positive linear relationship with a low detection limit of 02% (v/v). The relative standard deviation is 348%. Conclusions: Klebsiella sp. ME17 isolate is capable of utilizing CH₄. The microbial biosensing system of strain ME17 has been successfully applied to measure standard CH₄ sample with satisfactory results. Significance and Impact of the Study: This study suggests that certain strains of Klebsiella genus are capable of utilizing CH₄. Our proposed method appears very attractive for CH₄ measurement in coal mine.