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Updated: Jun 20, 2026

Agarose-Based Model Ecosystem for Cultivating Methanotrophs in a Methane-Oxygen Counter Gradient
Published on: September 6, 2024
Preferential cultivation of type II methanotrophic bacteria from littoral sediments (Lake Constance)
Ingeborg Bussmann1, Michael Pester, Andreas Brune
1LS Mikrobielle Okologie, Fachbereich Biologie, Universität Konstanz, Germany. ingeborg.bussmann@uni-konstanz.de
Abstract:
Most widely used medium for cultivation of methanotrophic bacteria from various environments is that proposed in 1970 by Whittenbury. In order to adapt and optimize medium for culturing of methanotrophs from freshwater sediment, media with varying concentrations of substrates, phosphate, nitrate, and other mineral salts were used to enumerate methanotrophs by the most probable number method. High concentrations (>1 mM) of magnesium and sulfate, and high concentrations of nitrate (>500 microM) significantly reduced the number of cultured methanotrophs, whereas phosphate in the range of 15-1500 microM had no influence. Also oxygen and carbon dioxide influenced the culturing efficiency, with an optimal mixing ratio of 17% O(2) and 3% CO(2); the mixing ratio of methane (6-32%) had no effect. A clone library of pmoA genes amplified by PCR from DNA extracted from sediment revealed the presence of both type I and type II methanotrophs. Nonetheless, the cultivation of methanotrophs, also with the improved medium, clearly favored growth of type II methanotrophs of the Methylosinus/Methylocystis group. Although significantly more methanotrophs could be cultured with the modified medium, their diversity did not mirror the diversity of methanotrophs in the sediment sample detected by molecular biology method.
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