Escalating Photobiological Hydrogen Production Using Engineered Selenium Nanoparticles

This study assessed the effect of selenium nanoparticles
(SeNPs),
a metalloid-based semiconducting NP, on the growth of the photosynthetic
bacterium Rhodopseudomonas palustris and its production of photofermentative hydrogen (H2)
metabolized from acetate. The addition of 0.1 mg/L SeNPs enhanced
the growth of R. palustris and increased
H2 production by 7.34% in the stationary phase. Furthermore,
the decoration of SeNPs with chitosan and vitamin E improved stability
and increased H2 production by 20.48 and 34.43%, respectively,
in growing R. palustris. Nitrogen-starved,
nongrowing R. palustris could increase
the H2 yield by fully oxidizing acetate. The decoration
of SeNPs with chitosan and vitamin E resulted in a 66.42 and 77.94%
increase in H2 production of nongrowing R. palustris, with yields of 1.06 and 1.08 mol/mol
acetate, respectively, which are comparable to reported yields metabolized
from 6-carbon hexose. Finally, the study provided evidence that SeNPs
augment H2 production by facilitating electron transfer
from photophosphorylation to the H2-producing enzyme. Therefore,
this study will enable the advanced optimization of photobiological
H2 production using engineered NPs.