Hybrid high-porosity rice straw infused with BiVO4 nanoparticles for efficient 2-chlorophenol degradation

In this work, the coupling of BiVO₄ nanoparticles with a highly porous material derived from rice straw (BiVO₄/RS composites) and the photocatalytic degradation of 2-chlorophenol (2-CP) in an aqueous solution was studied. The results indicated that BiVO₄/RS composites possessed a monoclinic structure. The morphologies of BiVO₄/RS composites consisted of spherical shapes of BiVO₄ particles coated on the RS adsorbent. The specific surface area of BiVO₄ increased from 1.9024 to 31.1153 m²/g after coating with RS adsorbent. A shift occurred in adsorption edge from 510 to 525 nm, corresponding to a reduction in band gap energy from 2.43 to 2.35 eV. The change in the optical adsorption edge and band gap of BiVO₄/RS composites may simultaneously result to the duplication of a structure caused by silicon species in rice straw, which was expected to be self-doped into the BiVO₄ crystal lattice during synthesis. The photocatalytic performance of 2-chlorophenol under visible irradiation clearly showed that BiVO₄/RS composites displayed the highest photocatalytic activities in comparison with other pure samples, which were 2 times higher than that of BiVO₄.     

The activity of the Synechocystis PCC6803 AbrB2 regulator of hydrogen production can be post-translationally controlled through glutathionylation

We show that the Synechocystis AbrB2 repressor of hydrogen production, down regulates the defence against oxidative stress. The single widely conserved cysteine of AbrB2 is also shown to play a crucial role in AbrB2 oligomerisation, and in AbrB2-mediated repression of the hydrogenase encoding operon (hoxEFUYH) and a wealth of other genes. Very interestingly, our results indicate that this cysteine is the target of glutathionylation, which affects the binding of AbrB2 on the hox operon-promoter DNA, as well as the stability of AbrB2 at the non-standard temperature of 39 °C. Similarly, we show that the cysteine of the other hoxEFUYH regulator AbrB1 can also be glutathionylated in vitro. These novel findings will certainly stimulate the in depth analysis of the influence of glutathionylation on the production of hydrogen, a field totally overlooked so far. They also emphasize on the evolutionary conservation of glutathionylation, a process mostly described in eukaryotes, so far.