3. Results and discussion
3.1. Enrichment and isolation
Enrichment cultures were grown on MJYTG medium and,
after 3 days of incubation, growth was observed at 60 C.
Meanwhile, H2 produced from these enriched cultures was
detected by a gas chromatograph. Seven enrichments were
obtained after three sequential transfers. Hydrothermal vent
samples used for these enrichments are described in Table 1.
These samples were mainly hydrothermal sulfides from the
Southwest Indian Ridge, East Pacific and South Atlantic. The
successful enrichment from different vent environments
demonstrated that fermentative hydrogen-generating microbes
could be widespread in hydrothermal vent fields. Further, the
bacterial diversity of enriched cultures was investigated by
construction of 16S rRNA gene clone libraries. Meanwhile,
bacterial isolation was conducted by streaking onto an
MJYTG medium solidified with agar in an anaerobic chamber.
After repeated streaking on plates, two different strains were
obtained and named H363 and H53214. Strain DY22619 was
obtained using FRPFO medium, as detailed in Zeng et al