Effects of Mo(VI) on phototrophic hydrogen production by Rhodobacter sphaeroides

• Published in: Environmental technology Vol. 32; no. 11; pp. 1279 - 1285
• Main Authors: Fang, Herbert H.P, Li, Ru Ying, Zhang, Tong
• Format: Journal Article
• Language: English
• Published: Abingdon TF 01.08.2011; Taylor & Francis Group; Taylor & Francis; Taylor & Francis Ltd
• Subjects: acetates; Acetylene; acetylene reduction; alcohols; Applied sciences; Bioelectric Energy Sources; Biomass; Bioreactors - microbiology; butyrates; Carbon; Carbon - metabolism; Conversion; Correlation analysis; environmental technology; Exact sciences and technology; Fatty Acids - metabolism; Fermentation; hydrogen; Hydrogen - analysis; Hydrogen - metabolism; Hydrogen production; lactate; Lactates; Lactic Acid - metabolism; molybdate; molybdenum; Molybdenum - metabolism; Molybdenum - pharmacology; nitrogenase; phototrophic; Phototrophic Processes; Pollution; propionic acid; Rhodobacter sphaeroides; Rhodobacter sphaeroides - drug effects; Rhodobacter sphaeroides - growth & development; Rhodobacter sphaeroides - metabolism; Sole; British Isles; Correlation; Rhodobacter sphaeroides; molybdate; Correlation analysis; phototrophic; Biomass; hydrogen; lactate; Hydrogen production
• ISSN: 1479-487X; 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2010.535176

Effects of Mo⁶⁺ concentration on phototrophic hydrogen production of Rhodobacter sphaeroides were investigated using lactate as the sole carbon source. Results showed that an increase of Mo⁶⁺ from nil to 1000 µg l⁻¹ led to increases in hydrogen yield, maximum production rate, conversion efficiency, biomass yield and lactate removal. At 100 µg‐Mo l⁻¹, the maximum rate was 12.0 ml h⁻¹ l⁻¹ with a conversion efficiency of 36.1%, the cell yields were 1.11 g‐cell g⁻¹‐lactate and 2.4 g‐cell g⁻¹‐TOC removed. Further increase of Mo⁶⁺ improved hydrogen production only marginally. Degradation of lactate by R. sphaeroides produced not just hydrogen but also acetate, butyrate, i‐valerate, i‐caproate, hexanoate and some unidentified organic intermediates, but did not produce propionate and alcohols. Nitrogenase activity, as measured by the acetylene reduction method, had no clear correlation with either Mo⁶⁺ concentration or hydrogen yield.