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Copper nanoparticles encapsulated by carbon (Cu-NPs@C) were synthesized by a two-step method by mixing cupric chloride and glucose in a solution, followed by carbonization. The microstructures and antibacterial activities of the Cu-NPs@C samples were characterized by TEM, XRD, XPS, nitrogen adsorption and antibacterial activity tests. Results indicated that the as-synthesized Cu-NPs had a FCC crystal structure and a spherical morphology of diameter 4-46 nm and were well dispersed in the porous graphitic carbon layers. When the mass ratio of cupric chloride to glucose was less than 1:5, the Cu-NPs@C were of pure metallic copper without any oxides, and were stable against ambient air oxidation. The Cu-NPs@C synthesized with a mass ratio of cupric chloride to glucose of 1:5 had a specific surface area of 418 m2/g, which showed much higher antibacterial activities against three different common bacteria (Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa) than pure nano-copper powder. It was believed that the carbon layers are responsible for capturing the bacteria while the copper ions released from the copper nanoparticles kill them. The outer carbon layers effectively protected the metallic copper inside from oxidation. These findings indicate that Cu-NPs@C can be used as a stable antibacterial agent in biomedical applications.

In this study, the immobilization with sodium alginate (SA) for cultivating microalgae in entrapped matrix gel beads was conducted for separating it from water. Batch experiments with a period of 5 days were carried out for free and immobilized Scenedesmus obliquus simultaneously under two trophic modes, to compare the removal performances of different initial ammonium (NH4+-N) concentrations. In both free and immobilized form, the positive C-dependent effect in mixotrophy and the negative N-dependent effect in heterotrophy were observed. And the performances of immobilized form were all superior to that of free form, which showed greater tolerance to high concentration, maximally representing 96.6 ± 0.1% removal in 50 mg/L of NH4+-N in mixotrophy. Assimilation of NH4+-N was the main removal pathway resulting the protein synthesis with the dominant component including glutamic acid (Glu), cystine (Cys), arginine (Arg) and proline (Pro). The results demonstrated a systematic understanding for NH4+-N removal in microalgae-based system.

Hou-Po-Da-Huang Tang (HPDHT) was used for the treatment of intestinal tract diseases in China. However, the underlying mechanisms via the intestinal bacteria remain largely unclear. Therefore, the aim of this study was to evaluate the metabolism of HPDHT by the human intestinal bacteria and its modulating effect on the intestinal bacteria. As a result, a total of 34 compounds were identified in HPDHT and transformed HPDHT (T-HPDHT). Among them, 12 metabolites were proved to be transformed by human intestinal bacteria. In vitro assays showed that T-HPDHT exhibited more significant elevation of free radical scavenging activity and suppression on the production of nitric oxide (NO) and TNF-α when comparing to HPDHT. Additionally, in vivo experiment confirmed that HPDHT significantly increased activity of superoxide dismutase (SOD), attenuated the malondialdehyde (MDA) and TNF-α levels in the conventional rats compared with that of pseudo germ-free (PGF) rats. In addition, HPDHT could significantly enhance the mean counts of Bifidobacterium and Lactobacillus and inhibit the growth of Clostridium, and Enterobacteriaceae, relative to controls. Due to the transformation of HPDHT being dependent on the bacterial strain, the effect of HPDHT on the selective growth of Bifidobacterium bifidum 29521 and Lactobacillus plantarum 8014 was evaluated. The kinetic parameters of microbial growth and prebiotic activity scores indicated that HPDHT could selectively stimulate the growth of the strains Bifidobacterium bifidum 29521 and Lactobacillus plantarum 8014. Taken together, metabolism of HPDHT by intestinal bacteria is a critical step towards the emergence of their anti-oxidation, anti-inflammation and prebiotic activities. This study provided valuable information for further pharmacological research on HPDHT.