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关键词： Graphene oxide   Biohydrogen   Thermophiles   Chemical oxygen demand   Nanoparticles  

摘要： Modern society envisions hydrogen (H-2) fuel to drive the transportation, industrial, and domestic sectors. Here, we explore use of graphene oxide nanoparticles (GO NPs) for greatly enhancing bio-H-2 production by a consortium based on Thermoanaerobacterium thermosaccharolyticum spp. Thermophilic batch bioreactors were set up at 60 degrees C and initial pH of 8.5 to assess the effects of GO NPs supplements on biohydrogen production. Under optimal GO NPs loading of 10 mg/L, the supplemented system yielded similar to 300% higher H-2 yield (6.78 mol H-2/mol sucrose) than control. Such an optimized system offered 73% H-2 purity and 85% conversion efficiency by promoted the desirable acetate fermentation pathway. Miseq Illumina sequencing tests revealed that the optimal levels of GO NPs did not alter the microbial composition of consortium.

关键词： Oil sands process water   Biotreatment   Circulating packed-bed bioreactor   Microbial diversity   Toxicity  

摘要： Effects of naphthenic acids (NAs) concentration (50-200 mg NA L-1;35-140 mg TOC L-1) and loading rate (1.4-1249 mg NA L-1 h(-1);1-874 mg TOC L-1 h(-1)) on removal efficiency, removal rate, and molecular distribution of NAs, and effluent toxicity were evaluated for biodegradation of commercial NAs mixture in circulating packed bed bioreactors (CPBBs). Increase of NAs concentration and loading rate (shorter residence times) increased the removal rate, while removal efficiency initially declined and then stabilized. The maximum biodegradation rates for 50, 100, 150, and 200 mg NA L-1 were 128.0, 321.7, 430.2, and 630.0 mg TOC L-1 h(-1) at loading rates of 218.5, 455.6, 673.5 and 874.0 mg TOC L-1 h(-1), respectively, with removal efficiencies of 58.6, 70.6, 63.9 and 72.1%. Analysis of influent and treated effluents with gas chromatography-mass spectrometry showed that molecular weight and cyclicity (C and Z numbers) affected the biodegradation, with low molecular weight acyclic NAs (C= 6-12) were the most amenable to biodegradation and those with intermediate and high molecular weights (C=13-22) and moderate cyclicity (Z= - 4, - 6) were the most recalcitrant. In the biofilm, Proteobacteria and Actinobacteria were the most abundant phyla, and Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the dominant classes. Toxicity analyses with Artemia sauna and Vibrio fischeri (Microtox) showed that high influent concentrations and loading rates (short residence times) led to higher NAs residual concentration and effluent toxicity. To design and operate large-scale CPBBs, intermediate loading rates and residence times that result in high removal efficiency, reasonable removal rates, and low toxicity are recommended. [GRAPHICS] .

关键词： Ketones  

摘要： Immobilized whole cells of Rhodotorula rubra MIM147 were used in a packed bed flow reactor for the enantioselective reduction of beta-ketonitriles and for the efficient production of a key building block for the synthesis of the antidepressant drug duloxetine. A choline chloride-glucose natural deep eutectic solvent (NADES) was employed with a dual function, as a co-solvent and as a source of glucose, fundamental for cofactor regeneration. To develop a fully automated protocol, an in-line purification procedure was also developed. Firstly, an in-line liquid-liquid extraction of the desired beta-hydroxynitriles was performed with a flow stream of ethyl acetate, then the unreacted ketone was trapped by a polymer-supported benzylamine. The optimized protocol allowed the obtainment of (S)-beta-hydroxynitriles in 80 minutes of residence time with >95% conversion and excellent e.e. (96-99%).

关键词： Dendrobium nobile Lindl   Temporary immersion bioreactor system   Immersion frequency   MeJA   Bioactive compound  

摘要： Background Dendrobium nobile Lindl. is an important pharmacopeial plant with medicinal and ornamental value. This study sought to provide a technical means for the large-scale production of total alkaloid in D. nobile. Seedlings were cultured in vitro using a temporary immersion bioreactor system (TIBS). The four tested immersion frequencies (min/h;5/2, 5/4, 5/6, and 5/8) influenced the production of biomass and total alkaloid content. In addition, to compare the effects of different concentrations of the phytohormone methyl jasmonate (MeJA) and treatment time on biomass and total alkaloid accumulation, MeJA was added to the TIBS medium after 50 days. Finally, total alkaloid production in semi-solid system (SSS), TIBS, and TIBS combined with the MeJA system (TIBS-MeJA) were compared. Results The best immersion frequency was found to be 5/6 (5 min every 6 h), which ensured appropriate levels of biomass and total alkaloid content in plantlets. The alkaloid content and production level of seedlings were the highest after treatment with 10 mu M MeJA separately for 20 and 30 days using TIBS. The maximum content (7.41 mg/g DW) and production level (361.24 mg/L) of total alkaloid on use of TIBS-MeJA were 2.32- and 4.69-fold, respectively, higher in terms of content, and 2.07- and 10.49-fold, respectively, higher in terms of production level than those on using of TIBS (3.20 mg/g DW, 174.34 mg/L) and SSS (1.58 mg/g DW, 34.44 mg/L). Conclusions Our results show TIBS-MeJA is suitable for large-scale production of total alkaloid in in vitro seedlings. Therefore, this study provides a technical means for the large-scale production of total alkaloid in D. nobile.

关键词： Biofilm   Dynamic membrane   Membrane fouling   Membrane bioreactor   Microbial community   Turbidity  

摘要： The concept of a novel living encapsulated self-forming dynamic bio-membranes (ESFDM) for an innovative wastewater treatment in membrane bioreactor (MBR) is presented in the current study. The active filtering membrane is encapsulated, and thus stabilized, between two support meshes with pore in micrometer size. The combination of activated sludge, the ESFDM and the cake layer formed external to the filtering module contributed to the treatment of municipal wastewater. COD concentration reductions (average value of 95.55 +/- 1.44%) by ESFDM bioreactor (ESFDMBR) were comparable to those obtained with a previously reported membrane bioreactor (MBR), where a conventional membrane was studied under the same operating conditions. The ESFDMBR, compared to the conventional MBR, obtained higher reductions of NH3-N, NO3-N and PO43-P concentrations. Increased removals of nitrogen-containing nutrients were ascribed to anoxic conditions reached in the ESFDM layer protected from the aeration by the external cake layer. Rate of increase of transmembrane pressure (TMP) per day in the ESFDMBR (0.03 kPa/day) was lower than the value obtained in the previously reported conventional MBR (8.08 kPa/day). Lower concentrations of fouling precursors in combination with the effective filtration capacity of the porous living ESFDM resulted in the reduction of the fouling rate. Analysis of microbiological community revealed that the microbial community structures in the mixed liquor and ESFDM were different. The ESFDM layer promoted growth of bacteria as indicated by the higher total cell count and higher microbial diversity compared to those observed in the mixed liquor. (C) 2021 Elsevier B.V. All rights reserved.

关键词： lipase   electrospinning   membrane bioreactor   macroscopic interface  

摘要： The core task for lipase catalytic system design is to construct a suitable oil-water interface for lipase distribution. In comparison to the micro-oil-water interface, the macro-oil-water interface (top oil-bottom water) served as a simplified lipase catalytic system that is more in line with industrial applications but limited in catalytic efficiency. Based on the assumption that one potential carrier can help lipase reach to the macro-oil-water interface, in the current work, sandwich-type lipase-membrane bioreactors (SLMBs) fabricated by a facile layer-by-layer electrospinning process were reported. These SLMBs were composed of a hydrophilic polyamide 6 nanofibrous membrane (NFM) as the bottom layer, a blended electrospun lipase/PVA NFM as the middle layer, and a hydrophobic EC/PU NFM as the top layer. The lipase loading can be controlled by altering the electrospinning time of the middle layer. Under the optimized conditions, the catalytic efficiency of the SLMBs was 2.05 times higher than that of free lipase. In addition, the SLMBs exhibit much better pH (high activity over a broad pH range of 5-10), temperature (retained 62% at 80 degrees C), storage stability (no loss of activity after being stored at 4 degrees C for 11 days), and reusability (retained 23% after five cycles) than free lipase.

关键词： Microalgae   Photobioreactor   Contaminants of emerging concern   Biodegradation   Mass balance  

摘要： The removal of 18 bisphenols at wastewater relevant concentrations (mu g L-1 range) was investigated and compared between Chlorella vulgaris cultures with pH adjusted to 6.8 and pH non-adjusted cultures where pH raised to above 10. Bisphenols with a high partition coefficient (log P > 6) partitioned to biomass soon after spiking, whereas bisphenols with a low partition coefficient (log P < 4) remained largely in the aqueous phase. Hydrophobic bisphenols and BPF isomers were removed to a large degree in pH adjusted conditions, while BPS and BPAF were the most recalcitrant The overall average removal after 13 days was similar in both experiments, with 72 +/- 2% and 73 +/- 5% removed in pH non-adjusted and pH adjusted series, respectively. The removal correlated with chlorophyll a concentration for most bisphenols meaning that algae played a crucial role in their removal, while culture pH also governed the removal of some compounds. (C) 2021 The Authors. Published by Elsevier B.V.

关键词： Ciprofloxacin (CIP)   Anaerobic membrane bioreactor (AnMBR)   16S rRNA gene-based community analysis   Performance  

摘要： The anaerobic membrane bioreactor (AnMBR) has considerable potential for treating wastewater, although there is very little data on the effect of antibiotics on AnMBR performance. This study examined the effect of Ciproflox-acin (CIP) -an antibiotic that can occur at high concentrations, and has a substantial impact on ecosystems, on AnMBR performance. The long-term (44 days) presence of 0.5 mg/L CIP in the feed did not have a strong effect on COD removal, volatile fatty acid (VFA) accumulation, or methane yield, but did affect the pH, soluble microbial products (SMPs) and suspended solids. However, at 4.7 mg/L CIP, a significant effect on all the parameters tested was seen. 16S rRNA gene-based community analysis demonstrated that CIP changed the phylogenetic structure and altered the species richness and diversity. The relative abundance of various genera was also changed, and this explained much of the change in AnMBR behavior. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Nitrate removal   Solid-phase denitrification   Biodegradable polymers   Microbial community  

摘要： In this study, a novel biodegradable PHBV/PLA/rice hulls (PPRH) composite was applied and tested as biofilm at-tachment carrier and carbon source in two bioreactors for biological denitrification process. The denitrification performance, effect of operational conditions and microbial community structure of PPRH biofilm were evalu-ated. The batch experiment results showed that PPRH-packed bioreactor could completely remove 50 mg L-1 of NO3--N at natural pH (ca. 7.5) and room temperature. The continuous flow experiments indicated that high NO3--N removal efficiency (77%-99%) was achieved with low nitrite (<0.48 mg L-1) and ammonia (<0.81 mg L-1) accumulation, when influent NO3--N concentration was 30 mg L-1 and hydraulic retention time was 2-6 h. Furthermore, the microbial community analysis indicated that bacteria belonging to genus Diaphorobacter in phylum Proteobacteria were the most dominant and major denitrifiers in denitrification. In summary, PPRH composite was a promising carbon source for biological nitrate removal from water and waste-water. (c) 2021 Elsevier B.V. All rights reserved.

关键词： 无泡式中空纤维膜生物反应器   中空纤维膜   膜材料   传质系数模型  

摘要： 无泡式中空纤维膜生物反应器(Membrane-aerated biofilm reactor,MABR)有效地将生物膜法污水处理技术和膜分离技术结合在一起,其具有无泡曝气和硝化反硝化一体的优点。回顾了MABR的发展历程,分析了MABR的基本结构和原理,介绍了MABR常用的膜材料及氧传质系数模型,阐述了MABR的影响因素,综述了国内外MABR的研究与应用现状,指出了MABR需要解决的问题并展望了该技术的未来发展。