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关键词： Prunus cerasifera   Micropropagation   Temporary immersion bioreactors RITA (R)   Molecular markers  

摘要： An efficient protocol for the micropropagation of Prunus cerasifera using temporary immersion bioreactors was described. One-node cuttings excised from field-grown plants were successfully disinfected using 12% sodium hypochlorite for 10 min. Immersion duration, frequency and medium composition in Bioreactors type RITA (R) were evaluated. A high multiplication rate was obtained using RITA (R) bioreactors containing Murashige and Skoog's medium (MS) supplemented with 1 mg L-1 N6-benzyladenine (BAP) and 1 mg L-1 indole-3-butyric acid (IBA) with 20 min/12 h as immersion time. RITA (R)-derived shoots were found to be more vigorous than those regenerated using the standard procedure. Higher levels of photosynthetic pigments were observed in shoots cultured in bioreactors, during the proliferation and rooting stages, which proved a certain degree of photo-autotrophy of RITA (R)-derived vitroplants. A high proportion of shoots was successfully rooted in an MS liquid medium supplemented with 1 g L-1 activated charcoal in RITA (R) bioreactors. During plant acclimatization, survival rates exceeding 80% were recorded. The genetic fidelity of micropropagated plants was investigated using inter simple sequence repeat (ISSR) markers. Results proved the generation of homogenous amplification profiles and thus supported the clonal fidelity of regenerated vitroplants.

关键词： Liquids   Wastewater   Nitrogen   Biotechnology   Water treatment  

摘要： The circulating-fluidized-bed bioreactor (CFBBR) is a promising technique for biological-nutrient removal (BNR) from wastewater. A simulation-based method for determining the hydraulic-retention time (HRT) and operating conditions of a CFBBR is proposed. When a CFBBR operates under the constant HRT and the constant operating conditions obtained by the proposed method, the effluent can meet the water-quality criteria in cases with composition disturbances and implementation errors. To reduce the HRT, two ways of adding a carbon source are investigated: (i) increasing the minimum carbon-nitrogen ratio of the fluctuating influent and (ii) adding a constant amount of a carbon source. The relationships between the minimum carbon-nitrogen ratio (TCOD increment) and the minimum HRT are obtained. These relationships are helpful for guiding the addition of a carbon source. A case study of a pilot-scale CFBBR for BNR is used to illustrate this method.

关键词： Membrane-aerated bioreactor   p-nitrophenol degradation   Denitrification   Detoxification pretreatment   Hydraulic flow state  

摘要： The chemical p-nitrophenol (PNP) is a priority pollutant, and PNP wastewater is highly toxic and resistant to biodegradation. The traditional physical and chemical methods (adsorption, extraction, and oxidation) for treating PNP wastewater have the disadvantages of complicated processes, high costs and secondary pollution generation. In this study, two integrated membrane-aerated bioreactor systems (RA and RB) with anoxic and aerated zones were constructed to enhance PNP biodegradation. The results showed that a helical silicone rubber membrane module displayed a high oxygen supply rate under a low membrane aeration pressure, and the hydraulic flow state of the reactor approached ideal mixing. At an influent PNP concentration of 500 mg/L, the average removal rates of PNP, chemical oxygen demand (COD) and total nitrogen (TN) reached 95.86%, 89.77%, and 94.81%, respectively, for RA and 89.48%, 74.26% and 64.78%, respectively, for RB, indicating efficient simultaneous PNP and nitrogen removal. Compared with that of RB, the pre-anoxic zone in RA not only performed detoxification pretreatment but also enhanced PNP degradation and denitrification effects, which relieved the biological treatment burden of the subsequent aerated zone. Based on these comprehensive analyses of reactor performance, the hydroquinone pathway might be the main route in the aerobic degradation of PNP.

关键词： Biofilms   Hydrogen   Sustainability   Chemical structure   Biotechnology  

摘要： Community assembly process (determinism vs stochasticity) determines the composition and diversity of a microbial community, and then shapes its functions. Understanding this complex process and its relationship to the community functions becomes a very important task for the applications of microbial biotechnology. In this study, we applied microbial electrolysis cells (MECs) with moderate species numbers and easily tractable functions as a model ecosystem, and constructed a series of biofilm communities with gradient biodiversity to examine the roles of community assembly in determining microbial community structure and functions. After stable biofilms formed, the best MEC reactor performances (e.g., gas productivity, total energy efficiency) were achieved in the group in which biofilms had the second highest a-diversity, and biofilms with even lower diversity showed declining performance. Null model analyses indicated that both deterministic and stochastic assembly played roles in the formation of biofilm communities. When deterministic assembly dominates this formation, the higher diversity of the biofilm community would generally show better reactor performance. However, when the stochasticity dominates the assembly process, the bioreactor performance would decline. This study provides novel evidence that the assembly mechanism could be one of the key processes to shift the functions, and proposes an important guidance for selecting the most efficient microorganisms for environmental biotechnologies.

关键词： State estimation   Sliding mode observers   LMIs   Robust control   Biological systems  

摘要： Super twisting observers (STOs) are particularly useful in situations where the process model is uncertain or in the presence of non measurable perturbations. Despite their increasing popularity, the selection of design parameters is delicate and is usually performed in an ad-hoc fashion. In this study, a robust design procedure is developed based on assumptions related to the boundedness of the uncertainties, and a computational procedure based on semi-definite programming is proposed and tested in simulation. Specifically, this procedure is applied to the design of STOs to monitor the internal substrate quota in cultures of micro-algae in photo-bioreactors, which is a key variable in the Droop model and cannot be measured on-line. Using the measurements of the concentrations of biomass and substrate in the culture medium, a state estimation scheme based on two STOs, one for the cell growth rate and the other for the substrate uptake rate, is therefore developed. (C) 2018 Published by Elsevier Ltd.

关键词： 厌氧膜生物反应器   膜污染   影响因素   控制策略  

摘要： 厌氧膜生物反应器(Anaerobic Membrane Bioreactor,AnMBR)是一种高效的厌氧生物处理系统,因其具有高容积负荷、低占地面积、优良的出水水质等优点受到了广泛关注。然而膜污染会导致膜组件性能下降,进而增加运行中能量消耗并降低膜组件寿命,是影响An MBR经济、技术可行性的关键因素。综述了An MBR的发展进程,分析了膜污染的影响因素,归纳总结了膜污染控制手段,并在此基础上展望了An MBR的未来研究方向,以期为An MBR的基础研究与推广应用提供理论指导与技术支撑。

关键词： Soluble microbial products   Membrane bioreactor   Thermodynamic analysis   Specific filtration resistance   Membrane fouling  

摘要： Soluble microbial products (SMPs) are the predominate foulants determining fouling extent in membrane bioreactors (MBRs). However, exact mechanism underlying their typical fouling behaviors remains unrevealed. In this study, the typical fouling behaviors of SMPs during initial operational period of a MBR were characterized. It was found that, although being low content, SMPs rather than sludge particulates preferentially adhered to membrane surface to accumulate a gel layer, and moreover, specific filtration resistance (SFR) of SMPs was approximately 700 times larger than that of the sludge particulates at operational day 3. According to energy balance principle, a unified thermodynamic mechanism underlying these fouling behaviors of SMPs was proposed. Thermodynamic analyses demonstrated that, the attractive interaction energy strength in contact between SMPs and membrane was larger by around 3700 times than that between sludge particulates and membrane, well explaining the extremely high adhesive ability of SMPs over sludge particlulates. Meanwhile, filtration through a SMPs layer was modelled and simulated as a thermodynamic process. Simulation on an agar gel showed that, about 92.6% of SFR was originated from mixing free energy change during filtration. Such a result satisfactorily interpreted the extremely high SFR of SMPs layer over sludge cake layer. The revealed thermodynamic mechanism underlying SMPs fouling behaviors significantly deepened understanding of fouling, and facilitated to development of effective fouling control strategies. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： 微藻   废水处理   藻菌共培养   光生物反应器   过程优化   藻菌絮体  

摘要： 微藻可以高效利用废水中的部分小分子有机质、氮和磷等污染物合成生物质,并达到处理废水的目的。近年来,利用微藻进行农业废水、工业废水、城市废水和含农药以及抗生素等有害废水的处理等有了一些新的尝试。本文中,笔者重点分析了微藻处理废水中藻种选育、藻菌共培养、藻菌絮体、工艺集成和反应器设计以及可持续综合开发等关键技术问题。其中,藻菌共培养可以发挥微藻和菌的各自优势,提高废水处理效率。藻菌絮体技术还具有便于采收的特点,具备进一步研究的潜力。针对不同废水的处理需求,笔者提出合理构建绿色可持续发展路线,推动微藻处理废水的更广泛应用。

关键词： 好氧填埋场   渗滤液回灌量   稳定化   生物降解   垃圾渗滤液  

摘要： 为了研究渗滤液回灌量对好氧填埋场稳定化进程的影响,通过模拟实验,探讨了不同回灌量时,好氧填埋场固相垃圾与渗滤液特性的变化趋势,填埋周期为122 d.结果表明,不同的渗滤液回灌下各反应器中填埋垃圾的含水率始终保持在70%左右;填埋过程中,回灌量为20%的反应器填埋垃圾中总有机质含量、(半纤维素+纤维素)/木质素比(Q)值与沉降量变化速度最快,至填埋结束时,总有机质含量与Q值较其他反应器低8.9%～14.6%和9.9%～16.9%,沉降量较其他反应器提高了6.6%～13.3%;在20%回灌量下,整个填埋周期填埋场所产渗滤液中的还原性有机物的量较10%、15%、30%和全回灌分别低9.8%、12.5%、17.8%和14.9%,氨氮在52 d,即降至25 mg/L,达到GB 16889—2008所规定的垃圾填埋场渗滤液氨氮排放浓度值,较其他反应器提前7～21 d.

关键词： 树参   扦插生根   基质   植物生根剂浓度  

摘要： 以当年生长健壮且无病虫害的树参木质化枝条为材料,研究不同扦插基质和植物生根剂浓度对树参扦插生根的影响,结果表明:不同基质、生根剂浓度和浸泡时间长短对树参扦插繁殖生根有显著影响,基质对树参扦插的影响最大,其次为生根剂的浸泡时间,生根剂的浓度影响最小。最佳组合为100%黄土、生根剂浓度为500mg/L和浸泡时间60min。