Biological denitrification using poly(butanediol succinate) as electron donor.

Poly(butanediol succinate) (PBS), a biodegradable polymer, was used as both solid carbon source and biofilm carrier for biological nitrate removal process, in which PBS was filled in a packed-bed bioreactor. The denitrification performance and the microbial diversity of biofilm attached on the surface of PBS were investigated. The experimental results showed that the volumetric denitrification rate was 0.60 kg m(-3) day(-1) when NO3-N loading rate was 0.63 kg m(-3) day(-1), and the average NO2-N concentration was below 0.20 mg L(-1). The effluent pH value decreased slightly from a range of 6.98-7.87 to 6.46-7.18. The analysis of microbial community structure of biofilm by pyrosequencing method showed that Proteobacteria was the most abundant phylum (89.87 %), and ß-Proteobacteria represented the most abundant class. Among the 76 identified genera, Dechloromonas (10.26 %), Alicycliphilus (9.15 %), Azospira (8.92 %), and Sinobacteraceae-uncultured (8.75 %) were the abundant genera. PBS, as a promising alternative carbon source, is a suitable solid carbon source and biofilm carrier for nitrate removal.

High-performance dielectric film capacitors based on cellulose/Al2O3 nanosheets/PVDF composites.

The design and preparation of novel renewable biomass-based dielectric composites have drawn great attention recently. Here, cellulose was dissolved in NaOH/urea aqueous solution, and Al2O3 nanosheets (AONS) synthesized by hydrothermal method were used as fillers. Then the regenerated cellulose (RC)-AONS dielectric composite films were prepared by regeneration, washing and drying. The two-dimensional AONS had a better effect on improving the dielectric constant and breakdown strength of the composites, so that the RC-AONS composite film with 5 wt% AONS content reached an energy density of 6.2 J/cm3 at 420 MV/m. Furthermore, in order to improve the dielectric energy storage properties of cellulose films in high humidity environment, the hydrophobic polyvinylidene fluoride (PVDF) was innovatively introduced to construct RC-AONS-PVDF composite films. The energy storage density of the prepared ternary composite films could reach 8.32 J/cm3 at 400 MV/m, which was 416 % improvement against that of the commercially biaxially oriented polypropylene (2 J/cm3), and could be cycled for >10,000 times under 200 MV/m. Concurrently, the water absorption of the composite film in humidity was effectively reduced. This work broadens the application prospect of biomass-based materials in the field of film dielectric capacitor.

Co-fermentation of sewage sludge and lignocellulosic biomass for production of medium-chain fatty acids.

Medium-chain fatty acids (MCFAs) production from sewage sludge and lignocellulosic biomass (fallen leaves and grass) was explored. Co-fermentation of sludge and lignocellulosic biomass significantly accelerated the caproate production and promoted the longer-chain MCFAs formation. Co-fermentation of sludge and grass achieved the highest caproate production of 89.50 mmol C/L, which was 18.04 % and 41.73 % higher than the mono-fermentation of grass and sludge, respectively. Co-fermentation of sludge and leaves produced 63.80 mmol C/L caproate, which was 11.09 % and 1.03 % higher than the mono-fermentation of leaves and sludge, respectively. Microbial analysis showed that co-fermentation enriched CE microbes like genus Clostridium_sensu_stricto_13, Caprocipiproducens, Terrisporpbacter and Praraclostridium, and suppressed the competitive microbes like genus norank_f_Caldilineaceae and Desulfomicrobium. Functional enzymes analysis revealed that co-fermentation of sludge and leaves promoted MCFAs production through strengthening reverse ß oxidation (RBO) pathway, while co-fermentation of sludge and grass stimulated MCFAs production by strengthening fatty acid biosynthesis (FAB) pathway.

pH-Responsive Lignin-Based Nanomicelles for Oral Drug Delivery.

A pH-stimuli amphiphilic lignin-based copolymer was prepared, and it could self-assemble to form spherical nanomicelles with the addition of "switching" water. The morphology, structure, and physical properties of micelles were characterized with transmission electron microscopy (TEM), nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), particle-size analysis, and zeta-potential measurement. In vitro drug release exemplified that the micelles were pH-sensitive, retaining more than 84.36% ibuprofen (IBU) in simulated gastric fluid (pH 1.5) and presenting a smooth release of 81.81% IBU in simulated intestinal fluid (pH 7.4) within 72 h. Cell culture studies showed that the nanomicelles were biocompatible and boosted the proliferation of human bone marrow stromal cells hBMSC and mouse embryonic fibroblast cells NIH-3T3. Interestingly, the nanomicelles inhibited the survival of human colon cancer cells HT-29 with a final survival rate of only 5.34%. Therefore, this work suggests a novel strategy to synthesize intelligent lignin-based nanomicelles that show a great potential as oral drug carriers.

Effects of rhamnolipid and Tween-80 on cellulase activities and metabolic functions of the bacterial community during chicken manure composting.

Metabolism by microorganisms is the basis of composting. In this study, the dynamic changes in the enzyme activity levels, bacterial community structure, and metabolism functions were investigated during chicken manure composting with an added bio-surfactant (rhamnolipid) or chemical surfactant (Tween-80). The results showed that rhamnolipid and Tween-80 improved the quality of the finished compost in terms of the C/N ratio, water-soluble carbon content, germination index, E4/E6 ratio, and the cellulase activity, especially with Tween-80. Furthermore, the bacterial communities were determined by high-throughput sequencing, and their metabolism functions were evaluated using the PICRUSt and Biolog methods. Tween-80 greatly influenced the bacterial community structure, where it enhanced the abundances of bacteria that degrade cellulose and lignin (e.g., members of the order Bacillales) and the capacities for carbohydrate and amino acid metabolism. Network analysis also showed that the order Bacillales was closely related to the metabolism of characteristic carbon sources, especially carbohydrates.

Effects of superabsorbent polymers on the abundances of antibiotic resistance genes, mobile genetic elements, and the bacterial community during swine manure composting.

Superabsorbent polymers (SAPs) are considered suitable amendments for reducing the selection pressure due to heavy metals and the abundances of antibiotic resistance genes (ARGs) during composting. In this study, three SAP (sodium polyacrylate) levels (0, 5, and 15mgkg-1 of compost) were applied and their effects on the abundances of ARGs, mobile genetic elements (MGEs), and the bacterial community were investigated. After composting, the abundances of ARGs and MGEs decreased to different extent, where the removal efficiencies for tetW, dfrA7, ermX, aac(6')-ib-cr and MGEs exceeded 90%. The high SAP concentration significantly reduced the abundances of ARGs and MGEs, and changed the microbial community. Redundancy analysis indicated that the moisture content mainly explained the changes in ARGs and MGEs. Network analysis determined the potential hosts of ARGs and MGEs, and their co-occurrence. The results suggested that applying 15mgkg-1 SAP is appropriate for reducing ARGs in compost.