Kinetics and Substrates Optimization on a Facultative and Methanotrophic Bacterium

Facultative methanotrophs reported recently could only utilize a few of C2, C3 and C4 compounds, which limited the application of methane oxidation in the engineering of greenhouse gas reduction due to the difficulty of cells propagation. A novel strain, Microbacterium sp. DH isolated from aged refuse, could utilize methane as well as multi-carbon compounds including organic acids and saccharides. Growth characteristics of M. sp. DH were studied with different C6 saccharides as carbon and energy sources, including glucose, mannose, sucrose, lactose, raffinose and starch, and the maximum specific cell growth rates (μmax) were derived using Boltzmann simulation and interpolation methods. The values of μmax were 0.076±0.008 hr-1, which indicated M. sp. DH could be propagated and enriched efficiently with C6 saccharides as substrates. Moreover, after repeated growth on starch or sucrose, a distinguishing characteristic was found that M. sp. DH still could thrivingly grow on methane. In summary, M. sp. DH could be suitable to mitigation of anthropogenic methane emission.