Comparison of calcium magnesium ferrite nanoparticles for boosting biohydrogen production.

Dark fermentation (DF) is an eco-friendly process that simultaneously achieves organic matter degradation and obtains hydrogen (H2). Nonetheless, low H2 yield mainly caused by poor activity of key microbes, is still a problem that requires being resolved. In this work, MgFe2O4 and Ca0.5Mg0.5Fe2O4 nanoparticles (NPs) were synthetized and served as additives to boost H2 form from DF. H2 productivity gradually increased with the rise of NPs, and declined when NPs exceeded their optimal dosages. The highest H2 yield was 183.6 ± 3.2 mL/g glucose at 100 mg/L of MgFe2O4 NPs, being 35.2 % higher than that of the control yield (135.8 ± 3.1 mL/g glucose). However, the highest H2 yield of 171.9 ± 2.5 mL/g glucose occurred at 400 mg/L of Ca0.5Mg0.5Fe2O4 NPs, increasing by 26.6 % over the control. Interestingly, the two NPs favored the butyric acid pathway for H2 synthesis. This provides guidance for multi-element oxide NPs used in DF.

Improved biohydrogen evolution through calcium ferrite nanoparticles assisted dark fermentation.

Dark fermentation (DF) is a green hydrogen (H2) production process, but it is far below the theoretical H2 yield. In this study, calcium ferrite nanoparticles (CaFe2O4 NPs) were produced to augment H2 yield via DF. The highest H2 yield of 250.1 ± 6.5 mL/g glucose was achieved at 100 mg/L CaFe2O4 NPs. Furtherincreasein CaFe2O4 NPs above 100 mg/L, such as 600 mg/L, would slightly lower H2 yield to 208.6 ± 2.6 mL/g glucose. The CaFe2O4 NPs in DF system released calcium and iron ions, promoting granular sludge formation andDF microbial activity. Soluble metabolites revealed that butyric acid was raised by CaFe2O4 NPs, which indicated the improved metabolic pathway for more H2. Microbial structure composition further illustrated that CaFe2O4 NPs could increase the abundance of dominant microbial populations, with the supremacy of Firmicutes up to 71.22 % in the bioH2 evolution group augmented with 100 mg/L CaFe2O4 NPs.

Comparison of copper and aluminum doped cobalt ferrate nanoparticles for improving biohydrogen production.

Two various materials, copper and aluminum doped cobalt ferrite nanoparticles (NPs) were fabricated for investigating their effects of addition amounts on hydrogen (H2) synthesis and process stability. CoCu0.2Fe1.8O4NPs enhanced H2 production more than CoAl0.2Fe1.8O4 NPs under same condition. The highest H2 yield of 212.25 ml/g glucose was found at optimal dosage of 300 mg/L CoCu0.2Fe1.8O4 NPs, revealing the increases of 43.17% and 6.67% compared with the control without NPs and 300 mg/L CoAl0.2Fe1.8O4 NPs groups, respectively. NPs level of more than 400 mg/L inhibited H2 generation. Further investigations illustrated that CoCu0.2Fe1.8O4 NPs were mainly distributed on extracellular polymer substance while CoAl0.2Fe1.8O4 NPs were mostly enriched on cell membrane, which facilitated electron transfer behavior. Community structure composition demonstrated that CoCu0.2Fe1.8O4 and CoAl0.2Fe1.8O4 separately caused a 9.67% and 9.03% increase in Clostridium sensu stricto 1 compared with the control reactor without NPs exposure.

Comparison of mesophilic and thermophilic dark fermentation with nickel ferrite nanoparticles supplementation for biohydrogen production.

In this work, nickel ferrite nanoparticles (NiFe2O4 NPs) was prepared to improve hydrogen (H2) production by dark fermentation. Moderate amounts (50-200 mg/L) promoted H2 generation, while excess NiFe2O4 NPs (over 400 mg/L) lowered H2 productivity. The highest H2 yields of 222 and 130 mL/g glucose were obtained in the 100 mg/L (37 °C) and 200 mg/L NiFe2O4 NPs (55 °C) groups, respectively, and the values were 38.6% and 28.3% higher than those in the control groups (37 °C and 55 °C). Soluble metabolites showed that NiFe2O4 NPs enhanced the butyrate pathway, corresponding to the increased abundance of Clostridium butyricum in mesophilic fermentation. The endocytosis of NiFe2O4 NPs indicated that the released iron and nickel favored ferredoxin and hydrogenase synthesis and activity and that NiFe2O4 NPs could act as carriers in intracellular electron transfer. The NPs also optimized microbial community structure and increased the levels of extracellular polymeric substances, leading to increased H2 production.

A modified HLA-A*0201-restricted CTL epitope from human oncoprotein (hPEBP4) induces more efficient antitumor responses.

We previously identified human phosphatidylethanolamine-binding protein 4 (hPEBP4) as an antiapoptotic protein with increased expression levels in breast, ovarian and prostate cancer cells, but low expression levels in normal tissues, which makes hPEBP4 an attractive target for immunotherapy. Here, we developed hPEBP4-derived immunogenic peptides for inducing antigen-specific cytotoxic T lymphocytes (CTLs) targeting breast cancer. A panel of hPEBP4-derived peptides predicted by peptide-MHC-binding algorithms was evaluated to characterize their HLA-A2.1 affinity and immunogenicity. We identified a novel immunogenic peptide, P40-48 (TLFCQGLEV), that was capable of eliciting specific CTL responses in HLA-A2.1/Kb transgenic mice, as well as in peripheral blood lymphocytes from breast cancer patients. Furthermore, amino-acid substitutions in the P40-48 sequence improved its immunogenicity against hPEBP4, a self-antigen, thus circumventing tolerance. We designed peptide analogs by preferred auxiliary HLA-A*0201 anchor residue replacement, which induced CTLs that were crossreactive to the native peptide. Several analogs were able to stably bind to HLA-A*0201 and elicit specific CTL responses better than the native sequence. Importantly, adoptive transfer of CTLs induced by vaccination with two analogs more effectively inhibited tumor growth than the native peptide. These data indicate that peptide analogs with high immunogenicity represent promising candidates for peptide-mediated therapeutic cancer vaccines.