High-efficiency hydrogen production by an anaerobic, thermophilic enrichment culture from an Icelandic hot spring.
Dark fermentative hydrogen production from glucose by a thermophilic culture (33HL), enriched from an Icelandic hot spring sediment sample, was studied in two continuous-flow, completely stirred tank reactors (CSTR1, CSTR2) and in one semi-continuous, anaerobic sequencing batch reactor (ASBR) at 58 degrees C. The 33HL produced H2 yield (HY) of up to 3.2 mol-H2/mol-glucose along with acetate in batch assay. In the CSTR1 with 33HL inoculum, H2 production was unstable. In the ASBR, maintained with 33HL, the H2 production enhanced after the addition of 6 mg/L of FeSO4 x H2O resulting in HY up to 2.51 mol-H2/mol-glucose (H2 production rate (HPR) of 7.85 mmol/h/L). The H2 production increase was associated with an increase in butyrate production. In the CSTR2, with ASBR inoculum and FeSO4 supplementation, stable, high-rate H2 production was obtained with HPR up to 45.8 mmol/h/L (1.1 L/h/L) and HY of 1.54 mol-H2/mol-glucose. The 33HL batch enrichment was dominated by bacterial strains closely affiliated with Thermobrachium celere (99.8-100%). T. celere affiliated strains, however, did not thrive in the three open system bioreactors. Instead, Thermoanaerobacterium aotearoense (98.5-99.6%) affiliated strains, producing H2 along with butyrate and acetate, dominated the reactor cultures. This culture had higher H2 production efficiency (HY and specific HPR) than reported for mesophilic mixed cultures. Further, the thermophilic culture readily formed granules in CSTR and ASBR systems. In summary, the thermophilic culture as characterized by high H2 production efficiency and ready granulation is considered very promising for H2 fermentation from carbohydrates.
Koskinen
Perttu E P
PE
Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland. perttu.koskinen@tut.fi
Lay
Chyi-How
CH
Puhakka
Jaakko A
JA
Lin
Ping-Jei
PJ
Wu
Shu-Yii
SY
Orlygsson
Jóhann
J
Lin
Chiu-Yue
CY
D019342:Acetic Acid / Q000378:metabolism; D000332:Aerobiosis; D000693:Anaerobiosis; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D019149:Bioreactors; D002087:Butyrates / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005296:Ferrous Compounds / Q000378:metabolism; D020459:Genes, rRNA; D005947:Glucose / Q000378:metabolism; D045482:Hot Springs / Q000382:microbiology*; D006358:Hot Temperature; D006859:Hydrogen / Q000378:metabolism*; D007055:Iceland; D008969:Molecular Sequence Data; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
D002087:Butyrates; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005296:Ferrous Compounds; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C020748:ferrous sulfate; D006859:Hydrogen; D005947:Glucose; D019342:Acetic Acid