Characterization of a halotolerant acetoclastic methanogen highly enriched from marine sediment and its application in removal of acetate

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• 作者：Akihisa Kita¹ ; ³ ; Kazuhito Suehira¹ ; Toyokazu Miura¹ ; ³ ; Yoshiko Okamura¹ ; ³ ; Tsunehiro Aki¹ ; ³ ; Yukihiko Matsumura² ; ³ ; Takahisa Tajima¹ ; ³ ; Naomichi Nishio¹ ; Yutaka Nakashimada¹ ; ³ ; ^{nyutaka@hiroshima-u.ac.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Halotolerant ; Acetoclastic methanogen ; Marine sediment ; Methanosaeta ; Methane fermentation ; Continuous culture ; Upflow anaerobic filter reactor
• 刊名：Journal of Bioscience and Bioengineering
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：121
• 期：2
• 页码：196-202
• 全文大小：989 K

文摘

A marine sediment collected from Hiroshima Bay was cultured in artificial seawater, containing 0.51 M NaCl and 60 mM acetate and was found to exhibit active methane production at 37°C. Following four successive serial dilutions of cultures in medium containing 0.51 M NaCl, 60 mM acetate, and antibiotics, the well-acclimated methanogen was found to exhibit growth over a range of NaCl concentration (between 0 M and 2.06 M). The specific growth rates of the highly enriched methanogen, termed strain H_A, in the absence of NaCl and in the presence of 1.54 M NaCl were estimated to be 0.037 h⁻¹ and 0.027 h⁻¹, respectively. The pH and temperature for optimum growth were determined to be 7.0–8.8 and 37°C, respectively. Although cells that had morphology similar to Methanosaeta sp. became dominant in the culture, methane production was still detected in the medium containing 0.51 M NaCl and other substrates such as methanol, formate, and methylamine, indicating contamination with other methanogens. The phylogenetic tree based on 16S rRNA gene sequences revealed that the strain H_A was closely related to Methanosaeta harundinacea 6Ac and 8Ac^T, with sequence similarity of 98% and 97%, respectively. The continuous removal of acetate with upflow anaerobic filter reactor for industrial use of strain H_A determined a methane production rate of 70 mM/d under condition of 0.51 M NaCl and successful methane production even under 1.54 M NaCl.