Photo-fermentative hydrogen production performance of a newly isolated Rubrivivax gelatinosus YP03 strain with acid tolerance

Abstract

Screening and excavating new photosynthetic bacteria with excellent hydrogen production performance is extremely important for improving the photo-fermentative hydrogen production. A new photosynthetic bacterium YP03 was isolated and identified to be Rubrivivax gelatinosus by morphological characterization and phylogenetic analysis. The effects of several key factors on hydrogen production performance were carried out. The results indicated that YP03 strain showed a preference for the carbon sources, and 5375 ± 398 mL/L of maximum hydrogen yield was obtained using butyrate medium. Meanwhile, YP03 strain could use several nitrogen sources to produce hydrogen, and glutamic acid was the optimum nitrogen source for hydrogen produced. Furthermore, YP03 exhibited better hydrogen production performance at initial pH 7.0, reaction temperature 33 °C and light intensity 5000 lux, and the maximum hydrogen production rate was 108.3 ± 12.4 mL/(Lh), which was relatively high compared with the previous reports by R. gelatinosus. Especially, the proper pH for hydrogen production by YP03 ranged from weak acid to neutral (6.5–7.0) and it still could produce hydrogen at pH 5.5 showing the characteristic of acid tolerance. It suggested that YP03 is a potential candidate for the integration of dark- and photo-fermentative hydrogen production. These findings contribute to our understanding of YP03 strain and provide a prospective photosynthetic bacterium for efficient hydrogen production in future research.