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排序方式: 共有832条查询结果,搜索用时 9 毫秒
101.
Pia Gruber Filipe Carvalho Marco P. C. Marques Brian O'Sullivan Fabiana Subrizi Dragana Dobrijevic John Ward Helen C. Hailes Pedro Fernandes Roland Wohlgemuth Frank Baganz Nicolas Szita 《Biotechnology and bioengineering》2018,115(3):586-596
102.
J.?C.?Santos S.?S.?Silva?S.?I.?MussattoEmail author W.?Carvalho M.?A.?A.?Cunha 《World journal of microbiology & biotechnology》2005,21(4):531-535
Summary Xylitol production from sugarcane bagasse hemicellulosic hydrolyzate was evaluated in a fluidized bed reactor operated in semi-continuous mode, using cells immobilized on porous glass. The fermentative process was performed during five successive cycles of 72 h each one. The lowest xylitol production occurred in the first cycle, where a high cell concentration (12 g l−1) was observed. In the subsequent cycles the xylitol concentration was ever increasing due to the cells adaptation to the medium. In the last one, 18 g xylitol l−1 was obtained with a yield factor of 0.44 g g−1 and volumetric productivity of 0.32 g l−1 h−1. 相似文献
103.
Punita?Mishra Pradeep?SrivastavaEmail author Subir?Kundu 《World journal of microbiology & biotechnology》2005,21(4):525-530
The production of Cephalosporin-C (CPC) a secondary metabolite, using a mold Acremonium chrysogenum was studied in a lab scale Internal loop air lift reactor. Cephalosporin-C production process is a highly aerobic fermentation process. Volumetric gas–liquid mass transfer coefficient (kLa) and viscosity (η) were evaluated, during the growth and production phases of the microbial physiology. An attempt has been made to correlate the broth viscosity, η and volumetric oxygen transfer coefficient, kLa during the Cephalosporin-C production in an air lift reactor. The impact of biomass concentration and mycelial morphology on broth viscosity has been also evaluated. The broth exhibits a typical non-Newtonian fermentation broth. Rheology parameters like consistency index and fluidity index are also studied. 相似文献
104.
The aerated stirred reactor (ASR) has been widely used in biochemical and wastewater treatment processes. The information describing how the activated sludge properties and operation conditions affect the hydrodynamics and mass transfer coefficient is missing in the literature. The aim of this study was to investigate the influence of flow regime, superficial gas velocity (U(G)), power consumption unit (P/V(L)), sludge loading, and apparent viscosity (mu(ap)) of activated sludge fluid on the mixing time (t(m)), gas hold-up (epsilon), and volumetric mass transfer coefficient (k(L)a) in an activated sludge aerated stirred column reactor (ASCR). The activated sludge fluid performed a non-Newtonian rheological behavior. The sludge loading significantly affected the fluid hydrodynamics and mass transfer. With an increase in the U(G) and P/V(L), the epsilon and k(L)a increased, and the t(m), decreased. The epsilon, k(L)a, and t(m), were influenced dramatically as the flow regime changed from homogeneous to heterogeneous patterns. The proposed mathematical models predicted the experimental results well under experimental conditions, indicating that the U(G), P/V(L), and mu(ap) had significant impact on the t(m), epsilon, and k(L)a. These models were able to give the t(m), epsilon, and k(L)a values with an error around +/-8%, and always less than +/-10%. 相似文献
105.
Eugenio Foresti Marcelo Zaiat Marcus Vallero 《Reviews in Environmental Science and Biotechnology》2006,5(1):3-19
Anaerobic digesters have been responsible for the removal of large fraction of organic matter (mineralization of waste sludge)
in conventional aerobic sewage treatment plants since the early years of domestic sewage treatment (DST). Attention on the
anaerobic technology for improving the sustainability of sewage treatment has been paid mainly after the energy crisis in
the 1970s. The successful use of anaerobic reactors (especially up-flow anaerobic sludge blanket (UASB) reactors) for the
treatment of raw domestic sewage in tropical and sub-tropical regions (where ambient temperatures are not restrictive for
anaerobic digestion) opened the opportunity to substitute the aerobic processes for the anaerobic technology in removal of
the influent organic matter. Despite the success, effluents from anaerobic reactors treating domestic sewage require post-treatment
in order to achieve the emission standards prevailing in most countries. Initially, the composition of this effluent rich
in reduced compounds has required the adoption of post-treatment (mainly aerobic) systems able to remove the undesirable constituents.
Currently, however, a wealth of information obtained on biological and physical-chemical processes related to the recovery
or removal of nitrogen, phosphorus and sulfur compounds creates the opportunity for new treatment systems. The design of DST
plant with the anaerobic reactor as core unit coupled to the pre- and post-treatment systems in order to promote the recovery
of resources and the polishing of effluent quality can improve the sustainability of treatment systems. This paper presents
a broader view on the possible applications of anaerobic treatment systems not only for organic matter removal but also for
resources recovery aiming at the improvement of the sustainability of DST. 相似文献
106.
Naoko Mizuno Christine C. Jao Ralf Langen Alasdair C. Steven 《The Journal of biological chemistry》2010,285(30):23351-23358
Endophilin A1 is a BAR (Bin/amphiphysin/Rvs) protein abundant in neural synapses that senses and induces membrane curvature, contributing to neck formation in presynaptic endocytic vesicles. To investigate its role in membrane remodeling, we used cryoelectron microscopy to characterize structural changes induced in lipid vesicles by exposure to endophilin. The vesicles convert rapidly to coated tubules whose morphology reflects the local concentration of endophilin. Their diameters and curvature resemble those of synaptic vesicles in situ. Three-dimensional reconstructions of quasicylindrical tubes revealed arrays of BAR dimers, flanked by densities that we equate with amphipathic helices whose folding and membrane insertion were attested by EPR. We also observed the compression of bulbous coated tubes into 70-Å-wide cylindrical micelles, which appear to mimic the penultimate (hemi-fission) stage of endocytosis. Our findings suggest that the adaptability of endophilin-lipid interactions underlies dynamic changes of endocytic membranes. 相似文献
107.
P.A. Wadegaonkar K.A. Bhagwat M.K. Rai 《Plant Cell, Tissue and Organ Culture》2006,84(2):100202-100204
Direct rooting from leaf explants of Withania somnifera was achieved on half strength Murashige and Skoog’s medium supplemented with 15 g l−1 sucrose, and different concentrations of growth regulators. Basal medium supplemented with 2.85 μM indoleacetic acid and
9.85 μM indolebutyric acid achieved maximum number of roots with 100% response. The roots were cultured on MS liquid medium
for the establishment of root-organ culture with the same plant growth regulators and incubated on an orbital shaker at 80 rpm
at 25 ± 2 °C. A root biomass of 6.15 ± 0.17 g was obtained after 5 weeks. When 1 g roots were inoculated to 2.5 l bubble column
reactor, 47 g roots were obtained after 6 weeks. The concentration of alkaloids was increased as compared to field grown roots.
The maximum concentration of withanolides (10 mg g−1 dry weight) was obtained in the bioreactor. 相似文献
108.
This work describes an alternative method for estimation of reaction rate of a biofilm process without using a model equation. A first principles model of the biofilm process is integrated with artificial neural networks to derive a hybrid mechanistic-neural network rate function model (HMNNRFM), and this combined model structure is used to estimate the complex kinetics of the biofilm process as a consequence of the validation of its steady state solution. The performance of the proposed methodology is studied with the aid of the experimental data of an anaerobic fixed bed biofilm reactor. The statistical significance of the method is also analyzed by means of the coefficient of determination (R2) and model efficiency (ME). The results demonstrate the effectiveness of HMNNRFM for estimating the complex kinetics of the biofilm process involved in the treatment of industry wastewater. 相似文献
109.
B. G. Cuevas J. Meléndez-Estrada R. Contreras M. A. Amezcua-Allieri 《Soil & Sediment Contamination》2012,21(1):31-41
The aim of this study was to evaluate anthracene removal using activated soil reactors, previously inoculated, under both aerobic and anaerobic conditions. In the reactors, the soil was maintained at 60% moisture (weight basis), room temperature, in the dark, and under constant agitation at 100 rpm. Two experiments were run during and after acclimatization to evaluate anthracene removal under both aerobic and anaerobic conditions. The first one took place during inoculum acclimatization using three different concentrations of anthracene (50, 100, and 500 mg anthracene/L per day) during 90 days. The second experiment took place after acclimatization (during 132 days). The results of anthracene removal were compared with controls in which no additional inoculum was added. During the two experiments, the behavior of pH, chemical oxygen demand (COD), and biogas production was evaluated. Results indicate that the bacterial community adapted for removal of anthracene became enriched through the acclimatization process. Anthracene biodegradation occurred in the soil model with both types of reactors (aerobic and anaerobic), but the rates and extent of biodegradation in the aerobic reactor were higher (95%) than those in anaerobic conditions (74%). Microbial activity also contributed to enhancing bioremediation in the soil by reducing anthracene sorption. 相似文献
110.
N. Qureshi B. S. Dien S. Liu B. C. Saha R. Hector M. A. Cotta S. Hughes 《Biotechnology progress》2012,28(5):1167-1178
Five reactor systems (free cell batch, free cell continuous, entrapped cell immobilized, adsorbed cell packed bed, and cell recycle membrane reactors) were compared for ethanol production from xylose using Escherichia coli FBR5. In the free cell batch and free cell continuous reactors (continuous stirred tank reactor‐CSTR) productivities of 0.84 gL?1 h?1 and 1.77 gL?1 h?1 were achieved, respectively. A cell recycle membrane reactor resulted in the highest productivity of 55.56 gL?1 h?1, which is an increase of 66‐fold (e.g., 6614%) over the batch reactor. Calcium alginate gel CSTR resulted in a productivity of 2.04 gL?1 h?1 whereas adsorbed cell packed bed reactor resulted in a productivity of 4.39 gL?1 h?1. In the five reactor systems, ethanol concentrations ranged from 18.9 to 40.30 gL?1 with metabolic yields from 0.44 to 0.51. Published 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012 相似文献