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关键词： transgenic hairy roots   sprinkle bioreactor   gene expression   anticancer   antimicrobial   antiviral activity  

摘要： Betulinic acid, which is found in transgenic roots of Senna obtusifolia (L.) *** & Barneby, is a pentacyclic triterpene with distinctive pharmacological activities. In this study, we report the differences in the content of betulinic acid and selected anthraquinones in transgenic S. obtusifolia hairy roots with overexpression of the PgSS1 gene (SOPSS2 line) and in transformed hairy roots without this genetic construct (SOA41 line). Both hairy root lines grew in 10 L sprinkle bioreactor. Additionally, the extracts obtained from this plant material were used for biological tests. Our results demonstrated that the SOPSS2 hairy root cultures from the bioreactor showed an increase in the content of betulinic acid (38.125 mg/g DW), compared to the SOA41 hairy root line (4.213 mg/g DW). Biological studies have shown a cytotoxic and antiproliferative effect on U-87MG glioblastoma cells, and altering the level of apoptotic proteins (Bax, p53, Puma and Noxa). Antimicrobial properties were demonstrated for both tested extracts, with a stronger effect of SOPSS2 extract. Moreover, both extracts showed moderate antiviral properties on norovirus surrogates.

关键词： anaerobic   cultivation   oxygen requirements   saccharomyces   nonconventional yeast  

摘要： All known facultatively fermentative yeasts require molecular oxygen for growth. Only in a small number of yeast species, these requirements can be circumvented by supplementation of known anaerobic growth factors such as nicotinate, sterols and unsaturated fatty acids. Biosynthetic oxygen requirements of yeasts are typically small and, unless extensive precautions are taken to minimize inadvertent entry of trace amounts of oxygen, easily go unnoticed in small-scale laboratory cultivation systems. This paper discusses critical points in the design of anaerobic yeast cultivation experiments in anaerobic chambers and laboratory bioreactors. Serial transfer or continuous cultivation to dilute growth factors present in anaerobically pre-grown inocula, systematic inclusion of control strains and minimizing the impact of oxygen diffusion through tubing are identified as key elements in experimental design. Basic protocols are presented for anaerobic-chamber and bioreactor experiments.

关键词： Butyric acid   Clostridium tyrobutyricum   Microbubbles   ATPase   Brewer's spent grain  

摘要： Microbubbles coupling fermentation is an efficient technology for improving oxygen transfer to aerobic microorganisms in a bioreactor containing an air sparger. However, the effect of this technology on anaerobic Clostridium tyrobutyricum, whose morphology develops viscous broth rheology and lumps impeding the nutrient mass transfer, has not been reported yet. Therefore, we evaluated the role of microbubbles coupling fibrous-bed bioreactor (MBFBB) on butyrate production by immobilized Clostridium tyrobutyricum cells obtained from renewable feedstock brewer's spent grain (BSG). Compared with the conventional fibrous-bed bioreactor (FBB) fermentation, two-fold shorter fermentation time and two-fold higher butyrate productivity were achieved by MBFBB-immobilized C. tyrobutyricum cells. Furthermore, long-term stability and reliability for butyrate production were obtained in ten cycle process using BSG hydrolysate. Finally, fed-batch fermentation using BSG hydrolysate produced a high butyrate titer of 43.68 g/L, with a significantly higher selectivity of 11.67, reducing the production cost of downstream processing. The results also indicated that butyrate productivity of 5.40 g/(L h were successfully obtained in BSG medium, thereby representing the highest productivity reported to date in C. tyrobutyricum from low-cost feedstocks. To our knowledge, this is also the first report related to microbial production of butyrate from BSG. Based on techno-economic analysis, it was demonstrated that the MBFBB-based fermentation process with BSG, was robust, economic and should underpin the future development of commercial biobutyrate production.

关键词： Bubble size   Bubble column bioreactor   Crypthecodinium cohnii   Docosahexaenoic acid   Cultivation  

摘要： Cultivation conditions especially agitation and aeration have critical roles on Crypthecodinium cohnii growth and docosahexaenoic acid (DHA) formation. In this study, for the first time, different air bubble sizes were considered, in a 5-L bubble column bioreactor;and the effect of bubble size on growth and on DHA production by dinoflagellate microalgae C. cohnii was investigated. The cultivation was carried out under 0.5 vvm aeration flow rate, 28 degrees C, and pH +/- 7. The highest yield of DHA (1.4 g DHA L-1) was achieved for 0.36-cm air bubble diameter;the corresponding biomass amount was 17.6 g. The suitable conditions during the logarithmic stage of growth were provided for 0.36-cm air bubble diameter, while oxygen limitation was observed in the culture medium afterwards. The concentration of the microalgal DHA was increased in oxygen limitation conditions. Our results indicate that the air bubble diameter is the most influencing factor on DHA production in a bubble column bioreactor. Current research indicates that optimum bubble size in bubble column bioreactor can lead to optimal conditions for growth and DHA production like two-stage oxygen supply feeding strategy.

关键词： Anaerobic membrane bioreactor   Conductive membrane   Electrocoagulation   Membrane fouling   Methanogenic pathway  

摘要： Serious membrane fouling limits the application of anaerobic membrane bioreactors (AnMBRs) in sewage treatment. Herein, a novel electrochemical AnMBR (eAnMBR) was established by integrating electrocoagulation and a conductive membrane into an AnMBR. Compared with the traditional AnMBR, TP average removal rate increased by 24.97% and the membrane service cycle extended by 109.68% in the eAnMBR. Low extracellular polymeric substance concentration and large floc size were found in the mixed liquid of the eAnMBR due to the combined effect of coagulation and electric field, which induced a porous and hydrophilic cake layer, resulting in excellent water permeation capabilities. Additionally, the conductive membrane cathode effectively suppressed membrane fouling by the electrostatic repulsion and gas scouring. In the eAnMBR, the presence of an electric field and iron ions enriched the diversity of the microbial community, which may improve the adaptation of biochemical systems to environmental changes.

关键词： Membrane bioreactor   Quorum quenching   Quorum sensing   Acyl homoserine lactone   Acinetobacter guillouiae  

摘要： A novel quorum quenching (QQ) strain, Acinetobacter guillouiae ST01, was isolated from a full-scale membrane bioreactor (MBR) and characterized for its QQ activities. Batch reactor studies at lab-scale showed that A. guillouiae ST01 exhibited higher QQ activity against acyl homoserine lactones (AHLs) with an oxo group compared to those without an oxo group. The organism was then inoculated (10%) in an MBR (Q-MBR) treating sewage over 48 days and was found to reduce quorum sensing (QS) activity by reducing AHL concentrations in the sludge and the biofilm of the Q-MBR. The concentration of polysaccharides was reduced up to 30% in both the biofilm and sludge relative to the control, whereas protein concentrations were reduced by 40% and 47% in the sludge and biofilm, respectively. The Q-MBR fouling rates were halved. These results indicate that A. guillouiae ST01 is a promising strain for biofouling reduction in MBR treating real wastewater.

关键词： Anaerobic membrane bioreactor   Reactor configurations   Membrane biofouling   16S rRNA gene-based amplicon sequencing   Neutral assembly  

摘要： Biofouling impedes the performance of anaerobic membrane bioreactors (AnMBR). Two reactors, one as an upflow attachment-growth AnMBR (UA-AnMBR) configuration, and the other, as a continuously stirred AnMBR (CS-AnMBR) were evaluated for differences in membrane fouling rate. TMP increment in UA-AnMBR was slower than CS-AnMBR, although both reactors had similar COD removal efficiency (ca. > 96%). Slower fouling rate for UA-AnMBR was related to lower total and viable cells, and thereby microbial activity compared to that in CSAnMBR. Acinetobacter and Methanobacterium that played keystone roles in anaerobic biofilm formation were not consistently prevalent on the membranes connected to UA-AnMBR. This is in contrast to both Acinetobacter and Methanobacterium consistently prevalent on the membranes connected to CS-AnMBR. The findings suggest that UA-AnMBR can alleviate membrane biofouling through changes in microbial activity and profile dynamics, and would be a suitable reactor configuration to adopt to achieve an efficient AnMBR for municipal wastewater treatment.

关键词： DNA methylation   Adventitious shoot regeneration   Liquid medium   Temporary-immersion bioreactor system   Plant growth regulators  

摘要： Blueberry (Vaccinium spp. L.) plants exhibit high potential of regeneration via adventitious shoot formation on a semi-solid medium followed by shoot elongation in a liquid medium under bioreactor systems. To find out whether DNA methylation plays a role during shoot elongation, we compared DNA methylation level in the regenerants of two in vitro-grown half-high blueberry (V. corymbosum L. x V. angustifolium Ait.) cultivars Patriot and Chippewa on a semi-solid medium (SSM) in glass bottles and in a liquid medium in temporary immersion bioreactors (TIB), via methylation-sensitive amplification polymorphism (MSAP) technique. The SSM was separately fortified with various combinations of two plant growth regulators, zeatin and thidiazuron for shoot regeneration but elongation was carried out using the same medium under both SSM and TIB systems with only zeatin. Zeatin at 9.2 mu M produced the maximum shoots in SSM and TIB for both cultivars, which varied from 30 to 33 in SSM and from 28 to 29 in TIB for Patriot and Chippewa, respectively. However, shoots proliferated in TIB were more vigorous. Noticeable changes in the methylation profiles were detected using MSAP in the regenerants grown in each type of culture system. The TIB system exhibited a significant increase in total methylation percentage (47-50%) in comparison to SSM (25-32%) in both cultivars. Similarly, the plants regenerated from TIB system were more polymorphic than those from SSM system. We describe here the effects of culture in vitro on DNA methylation that induced during the process of shoot elongation in two half-high blueberry cultivars. Key message In vitro shoot culture was achieved in half-high blueberry cultivars using a semi-solid and a liquid medium;plantlets developed from liquid medium showed higher level of DNA methylation alterations.

关键词： Alternating current   EMBR   EPS   Membrane fouling   Wastewater treatment  

摘要： A novel electro-assisted membrane bioreactor (EMBR) was built up with alternating current (AC) voltage applying on carbon nanotubes hollow fiber membranes (CNTs-HFMs) as the basic separation unit (AC-EMBR). Herein, a combination effect of electrostatic repulsion, electrochemical oxidation and translational motion behaviors was used to mitigate membrane fouling with +1.0 V for 1 min and -1.2 V for 1 min repeatedly applying on CNTs-HFMs. During the 73-day operation, the CNTs-HFMs in AC-EMBR exhibited a superior antifouling capability with a lower average fouling rate of 0.017 bar/d comparing to control groups, which were 0.021 bar/d in EMBR with CNTs-HFMs as cathode (C-EMBR), 0.025 bar/d in EMBR with CNTs-HFMs as anode (A-EMBR) and 0.029 bar/d in MBR without voltage, respectively. The AC potential led pollutants to loosely attach on membranes, which reduced irreversible fouling as well as reduced unrecoverable fouling levels. Bound extracellular polymeric substances (EPS) concentration in biomass of AC-EMBR was lower than those in the other reactors, which also contributed to suppressing membrane fouling. Meanwhile, an excellent effluent quality was obtained in AC-EMBR with COD removal rate higher than 96% and effluent NH4+-N concentration lower than 2 mg/L. Microbial community diversity has been promoted by AC electric field according to the microbial community analysis. The results of this study suggested the effectiveness of utilizing AC for membrane fouling mitigation and wastewater treatment in MBR systems. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Alkaline   Biofilm reactor   Biological sulphur recovery   Biotransformation   Saline solution   Sulphur oxidizing bacteria  

摘要： Concentrated sulphurous and saline streams, produced for example by pulp and paper and petrochemical industries, pose challenges for both environmental and processes management. In this study, the potential of biological recovery of S-0 from haloalkaline thiosulphate solution in a Thioalkalivibrio versutus amended continuous-flow fluidized bed bioreactor (FBBR) was investigated using different (12-5 h) hydraulic retention times (HRT) as well as physico-chemical means to separate the S-0 produced. S2O32- was biotransformed to SO42- and S-0 with the highest biotransformation efficiency of 99.9 %. At 7 h HRT, the capacity of the FBBR was reached, seen as incomplete thiosulphate conversion. S-0 production rate increased up to 6.3 +/- 0.6 g S/l/d at HRT 7 h, whilst the average S-0 yield was 27 +/- 2 %. The presence of biologically produced S-0 was visual and identified by scanning electron microscopy. Separation of S-0 from the effluent by centrifugation at 3417 relative centrifugal force (rcf) resulted in 93 % separation, while among the four tested coagulants, FeCl2 at 0.5 g/l resulted in 40 % separation. Also, FeCl2 enhanced thiosulphate biotransformation rates. In summary, continuous biological S-0 production followed by separation by centrifugation indicates potential for sulphur recovery from alkaline and saline industrial streams.