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991.
Spring S Lapidus A Schröder M Gleim D Sims D Meincke L Glavina Del Rio T Tice H Copeland A Cheng JF Lucas S Chen F Nolan M Bruce D Goodwin L Pitluck S Ivanova N Mavromatis K Mikhailova N Pati A Chen A Palaniappan K Land M Hauser L Chang YJ Jeffries CD Chain P Saunders E Brettin T Detter JC Göker M Bristow J Eisen JA Markowitz V Hugenholtz P Kyrpides NC Klenk HP Han C 《Standards in genomic sciences》2009,1(3):242-253
Desulfotomaculum acetoxidans Widdel and Pfennig 1977 was one of the first sulfate-reducing bacteria known to grow with acetate as sole energy and carbon source. It is able to oxidize substrates completely to carbon dioxide with sulfate as the electron acceptor, which is reduced to hydrogen sulfide. All available data about this species are based on strain 5575(T), isolated from piggery waste in Germany. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a Desulfotomaculum species with validly published name. The 4,545,624 bp long single replicon genome with its 4370 protein-coding and 100 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project. 相似文献
992.
Sebastiaan Hoekema Frank R. van Breukelen Marcel Janssen Johannes Tramper René H. Wijffels 《Biotechnology progress》2009,25(5):1343-1352
In this work, the dependency of the volumetric hydrogen production rate of ammonium‐limited Rhodobacter capsulatus chemostat cultures on their imposed biomass concentration and dilution rate was investigated. A deceleration‐stat experiment was performed by lowering the dilution rate from 1.0 d?1 to zero aimed at a constant biomass concentration of 4.0 g L?1 at constant incident light intensity. The results displayed a maximal volumetric hydrogen production rate of 0.6 mmol m?3 s?1, well below model predictions. Possibly the high cell density limited the average light availability, resulting in a sub‐optimal specific hydrogen production rate. To investigate this hypothesis, a gradient‐stat experiment was conducted at constant dilution rate of 0.4 d?1 at constant incident light intensity. The biomass concentration was increased from 0.7 to 4.0 g L?1 by increasing the influent ammonium concentration. Up to a biomass concentration of 1.5 g L?1, the volumetric hydrogen production rate of the system increased according to model predictions, after which it started to decline. The results obtained provide strong evidence that the observed decline in volumetric hydrogen production rate at higher biomass concentrations was at least partly caused by a decrease in light availability. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献
993.
Enzymatic hydrolysis of hybrid poplar treated by ammonia recycle percolation (ARP) was studied applying cellulase enzyme supplemented with additional xylanase or pectinase. The effect of xylanase addition was much more significant than pectinase addition. Conversion of ARP‐treated hybrid poplar to ethanol was carried out by simultaneous saccharification and fermentation (SSF) and SS and cofermentation (SSCF). The maximum ethanol yield observed from the SSCF experiment was 78% of theoretical maximum based on the total carbohydrate (glucan + xylan). The same feedstock was also treated by soaking in aqueous ammonia (SAA), a batch pretreatment process with lower severity than ARP. The test results indicated that relatively high severity is required to attain acceptable level of digestibility of hybrid poplar. In order to lower the severity of the pretreatment, addition of H2O2 was attempted in the SAA. Addition of H2O2 significantly enhanced delignification of hybrid poplar due to its oxidative degradation of lignin. Several different H2O2 feeding schemes and different temperature profiles were attempted in operation of the SAA to investigate the effects of H2O2 on degradation of lignin and carbohydrates in hybrid poplar. More than 60% of lignin in hybrid poplar was removed with stepwise‐increase of temperature (60–120°C after 4h of reaction). Increase of carbohydrate degradation was also observed under this condition. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献
994.
D. Karakashev S. M. Kotay E. Trably I. Angelidaki 《Journal of applied microbiology》2009,106(3):1041-1049
Aims: The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H2 ) producers from digested household solid wastes.
Methods and Results: A strict anaerobic extreme thermophilic H2 producing bacterial culture was enriched from a lab-scale digester treating household wastes at 70°C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80°C and an optimal pH 8·1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon sources. Growth on glucose produced acetate, H2 and carbon dioxide. Maximal H2 production rate on glucose was 1·1 mmol l−1 h−1 with a maximum H2 yield of 1·9 mole H2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated to the genera Bacillus and Clostridium. Relative abundance of the culture members, assessed by fluorescence in situ hybridization, were 87 ± 5% and 13 ± 5% for Bacillus and Clostridium , respectively.
Conclusions: An extreme thermophilic, strict anaerobic, mixed microbial culture with H2 -producing potential was enriched from digested household wastes.
Significance and Impact of the Study: This study provided a culture with a potential to be applied in reactor systems for extreme thermophilic H2 production from complex organic wastes. 相似文献
Methods and Results: A strict anaerobic extreme thermophilic H
Conclusions: An extreme thermophilic, strict anaerobic, mixed microbial culture with H
Significance and Impact of the Study: This study provided a culture with a potential to be applied in reactor systems for extreme thermophilic H
995.
Dunming Zhu Brooke A. Hyatt Ling Hua 《Journal of Molecular Catalysis .B, Enzymatic》2009,56(4):272-276
An alcohol dehydrogenase from the hyperthermophilic archaeon Pyrococcus furiosus (PFADH) effectively catalyzed the reductions of various substituted α-chloroacetophenones to furnish the corresponding (R)-configurated α-chlorohydrins with excellent enantiomeric purity. The co-factor NADH could be recycled with d-glucose dehydrogenase/d-glucose system or in a coupled substrate approach using iso-propanol as the hydrogen donor. The hydrogen transfer mode should be more cost-effective. Thus, the PFADH-catalyzed hydrogen transfer reductions of some substrates were carried out on the preparative scale, demonstrating that this enzyme would be a valuable biocatalyst for the preparation of chiral chlorohydrins of pharmaceutical interest. 相似文献
996.
Maoyin Li Yueyun HongXuemin Wang 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2009,1791(9):927-935
The phospholipase D (PLD) family in higher plants is composed of multiple members, and each of the Arabidopsis PLDs characterized displays distinguishable properties in activity regulation and/or lipid preferences. The molecular and biochemical heterogeneities of the plant PLDs play important roles in the timing, location, and amount of phosphatidic acid (PA) produced. PLD-catalyzed production of PA has been shown to play important roles in plant growth, development, and response to various stresses, including drought, salinity, freezing, and nutrient deficiency. PLD and PA affect cellular processes through different modes of action, including direct target protein binding and biophysical effects on cell membranes. Improved knowledge on the mechanism by which specific PLDs and PA mediate given plant responses will facilitate the understanding of the molecular processes that connect the stimulus perception on membranes to intracellular actions and physiological responses. 相似文献
997.
利用电化学活跃微生物协助电解发酵产氢 总被引:2,自引:0,他引:2
摘要:电解协助发酵产氢是在外源电解协助下,利用电化学活跃微生物在石墨阳极上生长达到彻底氧化因发酵产氢残存的有机酸,产生CO2、电子与质子,电子进入石墨阳极经导线传到铂阴极,而质子则穿过阳离子膜进入阴极池,在无氧环境下,通过外加电压和铂的催化下,电子与质子结合为氢。此过程电子回收率可达90%以上,产氢效率可达8-9mol H2/mol Glucose。这一战略从根本上克服发酵产氢的发酵障碍和代谢产物的反馈抑制,极大地提高了氢转化率,极有可能率先应用于能源作物原料的氢能转化、以及有机污水和有机废弃物处理。 相似文献
998.
999.
1000.
Nicoletta Guaragnella Antonella Bobba Ersilia Marra Sergio Giannattasio 《FEBS letters》2010,584(1):224-228
To investigate the role of cytochrome c (cyt c) release in yeast acetic acid-induced programmed cell death (AA-PCD), wild type (wt) and cells lacking metacaspase (Δyca1), cytochrome c (Δcyc1,7) and both (Δcyc1,7Δyca1) were compared for AA-PCD occurrence, hydrogen peroxide (H2O2) production and caspase activity. AA-PCD occurs in Δcyc1,7 and Δcyc1,7Δyca1 cells slower than in wt, but similar to that in Δyca1 cells, in which no cytochrome c release occurs. Both H2O2 production and caspase activation occur in these cells with early and extra-activation in Δcyc1,7 cells. We conclude that alternative death pathways can be activated in yeast AA-PCD, one dependent on cyt c release, which requires YCA1, and the other(s) independent on it. 相似文献