Arunsri Fangkum Saripan's research while affiliated with Thepsatri Rajabhat University and other places

The objective of this study was to optimize the culture conditions for simultaneous saccharification and fermentation (SSF) of cellulose for bio-hydrogen production by anaerobic mixed cultures in elephant dung under thermophilic temperature. Carboxymethyl cellulose (CMC) was used as the model substrate. The investigated parameters included initial pH, temperature and substrate concentration. The experimental results showed that maximum hydrogen yield (HY) and hydrogen production rate (HPR) of 7.22 +/- 0.62 mmol H-2/g CMCadded and 73.4 +/- 3.8 mL H-2/L h, respectively, were achieved at an initial pH of 7.0, temperature of 55 degrees C and CMC concentration of 0.25 g/L. The optimum conditions were then used to produce hydrogen from the cellulose fraction of sugarcane bagasse (SCB) at a concentration of 0.40 g/L (equivalent to 0.25 g/L cellulose) in which an HY of 7.10 +/- 3.22 mmol H-2/g cellulose(added). The pre-dominant hydrogen producers analyzed by polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. The lower HY obtained when the cellulose fraction of SCB was used as the substrate might be due to the presence of lignin in the SCB as well as the presence of Lactobacillus parabuchneri and Lactobacillus rhamnosus in the hydrogen fermentation broth. Copyright

Thermophilic bio-hydrogen production from xylan by anaerobic mixed cultures in elephant dung was conducted. The initial pH, temperature, and xylan concentration of 7.0, 55°C and 3.0 g/L, respectively, gave a respective maximum hydrogen yield (HY) and hydrogen production rate (HPR) of 12.16 mmol H2/g xylan and 61.30 mL H2/L.d. The optimum conditions were used to produce hydrogen from sugarcane bagasse (SCB) in which an HY of 2.60 mmol H2/g SCB and a HPR of 59.78 mL H2/L.d were obtained. The hydrogen producers present in both xylan and SCB fermentation broth were Thermoanaerobacterium thermosaccharolyticum and Clostridium sp.

Thermophilic hydrogen production from xylan by Thermoanaerobacterium thermosaccharolyticum KKU-ED1 isolated from elephant dung was investigated using batch fermentation. The optimum conditions for hydrogen production from xylan by the strain KKU-ED1 were an initial pH of 7.0, temperature of 55 °C and xylan concentration of 15 g/L. Under the optimum conditions, the hydrogen yield (HY), hydrogen production rate (HPR) and xylanase activity were 120.05 ± 15.07 mL H2/g xylan, 11.53 ± 0.19 mL H2/L h and 0.41 units/mL, respectively. The optimum conditions were then used to produce hydrogen from 62.5 g/L sugarcane bagasse (SCB) (equivalent to 15 g/L xylan) in which the HY and HPR of 1.39 ± 0.10 mL H2/g SCB (5.77 ± 0.41 mL H2/g xylan) and 0.66 ± 0.04 mL H2/L h, respectively, were achieved. In comparison to the other strains, the HY of the strain KKU-ED1 (120.05 ± 15.07 mL H2/g xylan) was close to that of Clostridium sp. strain X53 (125.40 mL H2/g xylan) and Clostridium butyricum CGS5 (90.70 mL H2/g xylan hydrolysate).

Background: Biological hydrogen production by microorganisms can be divided into two main categories i.e. 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. Results: Thermophilic hydrogen producer was isolated from elephant dung and identified as Thermoanaerobacterium thermosaccharolyticum 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. Conclusions: 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.