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Alkaliphilic methanogens from high-pH lake sediments

1986; Elsevier BV; Volume: 7; Issue: 2-3 Linguagem: Inglês

10.1016/s0723-2020(86)80011-x

1618-0984

David R. Boone, Suchada Worakit, Indra M. Mathrani, Robert A. Mah,

Anaerobic Digestion and Biogas Production

Five alkaliphilic methanogens were enriched and isolated from sediments of five lakes in the Wadi el Natrun of Egypt. Four of these were H2-oxidizing, CO2-reducing, rod-shaped methanogens from lakes having a low dissolved salt concentration. The pH values of these lakes were in the range of 8.3–9.3. One isolate was enriched and isolated from Bosa Lake of the Wadi el Naturn, whose pH was 9.7 and total dissolved solids content was about 250 g/l. Enrichment cultures from the low-salt lakes produced methane only from H2–CO2, and cultures from the high-salt lake (Bosa Lake) produced methane only from trimethylamine. Bacteria were isolated from each of these five enrichment cultures. The low-salt isolates used H2-CO2 as substrate, but not acetate, trimethylamine, methanol or formate. Analysis by Conway de Macario indicated no antigenic cross-reactions of the four low-salt isolates with any of a panel of 11 polyvalent antibodies produced against strains of rod or cocco-bacillus shaped methanogenic bacteria. Strain WeN5, the methanogen from the high-salt environment, catabolized trimethylamine and methanol but not H2-CO2, formate, nor acetate. It was an irregularly-shaped coccoid organism which grew individually and with occasional clumps and tetrads.