The fermentative hydrogen-producing characteristics of
strains H363, H53214, DY22619, which were isolated in this
study, and strain MV1087, which is the type species of genus
Caloranaerobacter, were studied. The cultivation conditions
for hydrogen production by strain H53214 were optimized by
response surface methodology (RSM), previously described
by Jiang et al. [30]. In this study, all experiments were carried
out in 150 ml serum bottles containing 20 ml of modified YTG
medium and 1% inoculum (v/v) under optimal conditions for
hydrogen production predicted by RSM: an initial pH of 7.7,
8.3 g L1 tryptone, 7.9 g L1 yeast, and 10 g L-1 glucose,
60 C. Prior to incubations, bottles were flushed with ultrahigh
pure nitrogen gas (99.999%) for 2 min and then capped
with rubber stoppers and closed with aluminum caps. The
bottles were shaken in an air bath at 120 rpm. After 24 h of
incubation, total hydrogen was measured by releasing the
pressure in the bottles using a syringe for concentration
analysis. All the experiments were carried out independently
in triplicate.