Enhanced photo-fermentative hydrogen production by synergistic effects of formed biofilm and added L-cysteine. (August 2019)

• Record Type: Journal Article
• Authors: Wen, Han-Quan; Xing, De-Feng; Xie, Guo-Jun; Yin, Tian-Ming; Ren, Nan-Qi; Liu, Bing-Feng
• Is Part Of: Renewable energy. Volume 139(2019)
• Page Start: 643
• Page End: 650
• Publication Date: 2019-08
• Subjects: Photo-fermentative hydrogen production -- L-cysteine -- Biofilm -- EPS -- eDNA; BR biofilm reactor -- CR control reactor -- eDNA extracellular DNA -- PFHP Photo-fermentative hydrogen production -- PFB photo-fermentative bacteria -- ORP low oxygen-redox potential -- OD optical density -- FID flame ionization detector -- SEM scanning electron microscope; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2019.02.127
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: In this work, the synergistic effects of L-cysteine and biofilm on the performance of reactor were investigated in the photo-fermentative biofilm reactor. Both L-cysteine and biofilm could enhance the performance of reactor for producing hydrogen. The optimal L-cysteine concentrations in the biofilm reactor (BR) and control reactor (CR, reactor with no biofilm) were 0.5 g/L and 0.75 g/L, respectively. In addition, the maximum cumulative hydrogen volume (3500 ± 170 mL/L), substrate conversion efficiency (79.4 ± 4.0%) and hydrogen yield 867 ± 43 mL/g (acetate) were obtained in the BR at L-cysteine concentration of 0.5 g/L. It is intriguing that extracellular DNA (eDNA) occupied 50% of EPS, which could play a key role in hydrogen production. Biofilm could decrease EPS concentration of cells in the BR at each L-cysteine concentration to divert more energy into hydrogen. The moderate L-cysteine concentration could improve bacterial growth and regulate the EPS to promote the biofilm formation and enhance hydrogen production. Thus, the regulation of L-cysteine concentration will be a practical method to enhance hydrogen production by the biofilm reactor. Highlights: Both the L-cysteine and biofilm could enhance photo-H2 production. H2 production in the BR is regulated by biofilm bacteria as "leader wolf". Lower EPS concentration was favorable to produce more hydrogen. Protein and eDNA were the important compositions of EPS and construct the biofilm.