Co-Culture of Halotolerant Bacteria to Produce Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Using Sewage Wastewater Substrate.

The focus of the current study was the use of sewage wastewater to obtain PHA from a co-culture to produce a sustainable polymer. Two halotolerant bacteria, Bacillus halotolerans 14SM (MZ801771) and Bacillus aryabhattai WK31 (MT453992), were grown in a consortium to produce PHA. Sewage wastewater (SWW) was used to produce PHA, and glucose was used as a reference substrate to compare the growth and PHA production parameters. Both bacterial strains produced PHA in monoculture, but a copolymer was obtained when the co-cultures were used. The co-culture accumulated a maximum of 54% after 24 h of incubation in 10% SWW. The intracellular granules indicated the presence of nucleation sites for granule initiation. The average granule size was recorded to be 231 nm; micrographs also indicated the presence of extracellular polymers and granule-associated proteins. Fourier transform infrared spectroscopy (FTIR) analysis of the polymer produced by the consortium showed a significant peak at 1731 cm-1, representing the C=O group. FTIR also presented peaks in the region of 2800 cm-1 to 2900 cm-1, indicating C-C stretching. Proton nuclear magnetic resonance (1HNMR) of the pure polymer indicated chemical shifts resulting from the proton of hydroxy valerate and hydroxybutyrate, confirming the production of poly(3-hydroxybutyrate-co-3-hydroxy valerate) (P3HBV). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay showed that the copolymer was biocompatible, even at a high concentration of 5000 µg mL-1. The results of this study show that bacterial strains WK31 and 14SM can be used to synthesize a copolymer of butyrate and valerate using the volatile fatty acids present in the SWW, such as propionic acid or pentanoic acid. P3HBV can also be used to provide an extracellular matrix for cell-line growth without causing any cytotoxic effects.

The financial sustainability of the World Health Organization and the political economy of global health governance: a review of funding proposals.

The World Health Organization (WHO) continues to experience immense financial stress. The precarious financial situation of the WHO has given rise to extensive dialogue and debate. This dialogue has generated diverse technical proposals to remedy the financial woes of the WHO and is intimately tied to existential questions about the future of the WHO in global health governance. In this paper, we review, categorize, and synthesize the proposals for financial reform of the WHO. It appears that less contentious issues, such as convening financing dialogue and establishing a health emergency programme, received consensus from member states. However, member states are reluctant to increase the assessed annual contributions to the WHO, which weakens the prospect for greater autonomy for the organisation. The WHO remains largely supported by earmarked voluntary contributions from states and non-state actors. We argue that while financial reform requires institutional changes to enhance transparency, accountability and efficiency, it is also deeply tied to the political economy of state sovereignty and ideas about the leadership role of the WHO in a crowded global health governance context.

Graphene Derivative in Magnetically Recoverable Catalyst Determines Catalytic Properties in Transfer Hydrogenation of Nitroarenes to Anilines with 2-Propanol.

Here, we report transfer hydrogenation of nitroarenes to aminoarenes using 2-propanol as a hydrogen source and Ag-containing magnetically recoverable catalysts based on partially reduced graphene oxide (pRGO) sheets. X-ray diffraction and X-ray photoelectron spectroscopy data demonstrated that, during the one-pot catalyst synthesis, formation of magnetite nanoparticles (NPs) is accompanied by the reduction of graphene oxide (GO) to pRGO. The formation of Ag0 NPs on top of magnetite nanoparticles does not change the pRGO structure. At the same time, the catalyst structure is further modified during the transfer hydrogenation, leading to a noticeable increase of sp2 carbons. These carbons are responsible for the adsorption of substrate and intermediates, facilitating a hydrogen transfer from Ag NPs and creating synergy between the components of the catalyst. The nitroarenes with electron withdrawing and electron donating substituents allow for excellent yields of aniline derivatives with high regio and chemoselectivity, indicating that the reaction is not disfavored by these functionalities. The versatility of the catalyst synthetic protocol was demonstrated by a synthesis of an Ru-containing graphene derivative based catalyst, also allowing for efficient transfer hydrogenation. Easy magnetic separation and stable catalyst performance in the transfer hydrogenation make this catalyst promising for future applications.

Facile Synthesis of Magnetically Recoverable Pd and Ru Catalysts for 4-Nitrophenol Reduction: Identifying Key Factors.

This paper reports the development of robust Pd- and Ru-containing magnetically recoverable catalysts in a one-pot procedure using commercially available, branched polyethyleneimine (PEI) as capping and reducing agent. For both catalytic metals, ∼3 nm nanoparticles (NPs) are stabilized in the PEI shell of magnetite NPs, whose aggregation allows for prompt magnetic separation. The catalyst properties were studied in a model reaction of 4-nitrophenol hydrogenation to 4-aminophenol with NaBH4. A similar catalytic NP size allowed us to decouple the NP size impact on the catalytic performance from other parameters and to follow the influence of the catalytic metal type and amount as well as the PEI amount on the catalytic activity. The best catalytic performances, the 1.2 min-1 rate constant and the 433.2 min-1 turnover frequency, are obtained for the Ru-containing catalyst. This is discussed in terms of stability of Ru hydride facilitating the surface-hydrogen transfer and the presence of Ru4+ species on the Ru NP surface facilitating the nitro group adsorption, both leading to an increased catalyst efficiency. High catalytic activity as well as the high stability of the catalyst performance in five consecutive catalytic cycles after magnetic separation makes this catalyst promising for nitroarene hydrogenation reactions.

Auxin producing non-heterocystous Cyanobacteria and their impact on the growth and endogenous auxin homeostasis of wheat.

Four non-heterocystous cyanobacterial strains isolated from rhizosphere and soil surface mat of rice, wheat, and maize were identified by 16S rRNA gene sequencing and evaluated for auxin production as well as growth promotion of wheat. Isolated strains produced a diverse amount of auxin in BG11 media supplemented with different concentrations of L-tryptophan. The amount of auxin detected with colorimetric methods was higher as compared to GC-MS analysis. Auxin production by cyanobacterial strains in BG 11 medium supplemented with 250 µg ml(-1) L-tryptophan ranged from 0.20 to 1.63 µg ml(-1) IAA as revealed by gas chromatography and mass spectrometric (GC-MS) analysis. In a hydroponic growth system, the vegetative growth of wheat was stimulated appreciably by inoculation with cyanobacterial strains. The endogenous auxin content of wheat was significantly correlated with the exogenous auxin production of the cyanobacterial strains. It was observed that cyanobacterial strains produced more endogenous and exogenous auxin in the presence of a plant, showing that plants might be releasing some signals responsible for higher auxin production by cyanobacterial cultures. It was concluded that the auxin producing potential of cyanobacterial strains can be exploited for the promotion of wheat growth.