Optimization of volatile fatty acids and hydrogen production from Saccharina japonica: acidogenesis and molecular analysis of the resulting microbial communities

• Published in: Applied microbiology and biotechnology 2015-04, Vol.99 (7), p.3327-3337
• Main Authors: Jung, Kwonsu, Kim, Woong, Park, Gwon Woo, Seo, Charles, Chang, Ho Nam, Kim, Yeu-Chun
• Format: Article
• Language: English
• Subjects: Acinetobacter; Algae; Alkanesulfonic Acids - pharmacology; Alternative energy sources; Anaerobiosis; Analysis; bacterial communities; beta-cyclodextrin; beta-Cyclodextrins - pharmacology; Biodiesel fuels; Bioenergy and Biofuels; Biofuels; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Biotechnology - instrumentation; Biotechnology - methods; Chemical oxygen demand; Chloroform; Chloroform - pharmacology; Clostridium; Escherichia; Fatty acids; Fatty Acids, Volatile - biosynthesis; Hydrocarbons, Iodinated - pharmacology; Hydrogen; Hydrogen - metabolism; Hydrogen production; Life Sciences; Methane - metabolism; methanogens; Microbial activity; Microbial Consortia - drug effects; Microbial Consortia - genetics; Microbial Genetics and Genomics; Microbiology; Microorganisms; Phaeophyceae - cytology; Phaeophyceae - drug effects; Phaeophyceae - metabolism; Polymerase chain reaction; quantitative polymerase chain reaction; response surface methodology; RNA, Ribosomal, 16S; Saccharina japonica; Studies; Temperature; volatile fatty acids
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-015-6419-2

Response surface methodology (RSM) was used to optimize the production of volatile fatty acids (VFAs) and hydrogen from mixed anaerobic cultures of Saccharina japonica with respect to two independent variables: methanogenic inhibitor concentration and temperature. The effects of four methanogenic inhibitors on acidogenic processes were tested, and qualitative microbial analyses were carried out. Escherichia, Acinetobacter, and Clostridium were the most predominant genera in samples treated with chloroform (CHCl₃), iodoform (CHI₃), 2-bromoethanesulfonate (BES), or β-cyclodextrin (β-CD), respectively. RSM showed that the production of VFAs reached a peak of 12.5 g/L at 38.6 °C in the presence of 7.4 g/L β-CD; these were the conditions under which hydrogen production was also nearly maximal. The quantitative polymerase chain reaction (qPCR) showed that shifts in the bacterial community population correlated with the concentrations of β-CD indicating that this compound effectively inhibited methanogens.