Biological hydrogen production by microorganisms can be divided into two main
photosynthetic organisms that produce hydrogen using light as energy source and
anaerobic bacteria that produce hydrogen via dark fermentation. Dark fermentative hydrogen
production by anaerobic bacteria has the advantages of a higher HPR without illumination and of the
capability to convert various kinds of substrate.
Thermophilic hydrogen producer was isolated from elephant dung and identified as
KKU-ED1 by 16S rRNA gene analysis, which was
further used to produce hydrogen from mixed pentose sugar i.e.
, xylose/arabinose. The optimum
conditions for hydrogen production from mixed xylose/arabinose by KKU-ED1 were a 1:1
xylose/arabinose mixture at the total concentration of 5 g/L, initial pH of 6.5 and temperature of 55ºC.
Under the optimum conditions, hydrogen from sugar derived from acid-hydrolyzed sugarcane bagasse
at a reducing sugar concentration were achieved. Soluble metabolite product (SMP) was
predominantly acetic acid indicating the acetate-type fermentation.
The strain KKU-ED1 appeared to be a suitable candidate for thermophilic fermentative
hydrogen production from hemicellulosic fraction of lignocellulosic materials due to its ability to use
various types of carbon sources.