Feasibility study on fermentative conversion of raw and hydrolyzed starch to hydrogen using anaerobic mixed microflora

Ching Hsiung Wang, Wei Bin Lu, Jo Shu Chang

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

In this work, H2 was produced by anaerobic mixed microflora with phosphate-buffered medium containing starch or enzyme-treated starch hydrolyzate as the carbon substrate. The effect of pH on H2-producing performance was examined for cultures converting raw starch or hydrolyzed starch into H2. Response surface methodology was utilized to determine the best condition (41 {ring operator} C, pH 5.2, 2.1% (v/v) enzyme dosage, 27 h reaction time) for starch hydrolysis with concentrated crude amylase obtained from Bacillus subtilis ATCC 21332. The mixed culture was able to produce H2 at an optimal pH of 7.0 irrespective of raw or hydrolyzed starch. Direct starch fermentation attained a highest maximum H2 production rate (Rmax), overall H2 production rate (Roverall), and H2 yield (YH2) of 25.6 ml/h, 88 ml/h/l, and 5.28 mmol H2/g starch (4.64 mmol H2/g COD), respectively. In contrast, using hydrolyzed starch as the substrate gave rise to much better H2 producing performance, as the highest Rmax, Roverall, and YH2 values increased to 43.1 ml/h, 210 ml/h/l, and 6.1 mmol H2/g COD, respectively. This clearly demonstrates the advantage of using hydrolyzed starch for fermentative H2 production. The soluble metabolites consisted primarily of acetate (HAc), ethanol (EtOH), butyrate (HBu), and 2,3 butandiol. The amount of H2 produced from raw and hydrolyzed starch (especially, raw starch) could be estimated from formation of HAc and HBu known to stoichiometrically correlate with H2 production.

Original languageEnglish
Pages (from-to)3849-3859
Number of pages11
JournalInternational Journal of Hydrogen Energy
Volume32
Issue number16
DOIs
Publication statusPublished - 2007 Nov 1

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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