Origin of CO2 as the main carbon source in syngas-to-methanol process over Cu: theoretical evidence from a combined DFT and microkinetic modeling study

2020 ◽  
Vol 10 (10) ◽  
pp. 3346-3352 ◽  
Author(s):  
Dongyang Xu ◽  
Panpan Wu ◽  
Bo Yang

A theoretical study combining DFT and microkinetic modeling provides evidence that CO2 is the main carbon source in methanol synthesis from syngas (CO, CO2 and H2) over Cu.

1972 ◽  
Vol 129 (2) ◽  
pp. 263-272 ◽  
Author(s):  
A. G. Dickerson

Evidence suggests that sucrose is the main carbon source for growth of Claviceps spp. in the parasitic condition. The sucrose acts as substrate for an active β-fructofuranosidase, produced by the fungus, which in the first instance converts the disaccharide into glucose and an oligofructoside. In this way, 50% of the glucose, supplied as sucrose, is made available to the parasite for assimilation. Subsequent action of the enzyme on both sucrose and the oligofructoside leads to the release of more glucose and the formation of additional oligosaccharides. The structures of the main oligosaccharides formed have been elucidated and the interactions of each compound studied. In experiments with purified enzyme in vitro the interaction of the oligosaccharides is rapid but in culture they are assimilated only slowly; in each case some free fructose is liberated. Free fructose is not assimilated in the presence of glucose and, further, inhibits growth at concentrations which might be expected to occur in the parasitic condition. A dual role has been suggested for the enzyme, with sucrose as substrate, in which glucose is made available to the growing parasite, while at the same time transfer of the fructose to form oligosaccharides prevents it from accumulating at inhibitory concentrations. Ultimately, when glucose becomes limiting, the fungus will adapt to fructose assimilation.


2012 ◽  
Vol 35 (6) ◽  
pp. 897-906 ◽  
Author(s):  
M. Sousa ◽  
V. M. M. Melo ◽  
S. Rodrigues ◽  
H. B. Sant’ana ◽  
L. R. B. Gonçalves

2003 ◽  
Vol 58 (9-10) ◽  
pp. 708-712 ◽  
Author(s):  
Telma Elita Bertolin ◽  
Willibaldo Schmidell ◽  
Alfredo E. Maiorano ◽  
Janice Casara ◽  
Jorge A. V. Costa

AbstractIt was the objective of the present study to increase the production of glucoamylase by Aspergillus awamori through solid state fermentation, using wheat bran as the main carbon source and (NH4)2SO4, urea, KH2PO4, glucose, maltose and starch as additional nitrogen, phosphorus, and carbon sources. The production of glucoamylase is strongly influenced by N and C sources. A 100% increase was observed when the (NH4)2SO4 was replaced by urea, with C/N = 4.8, using maltose as the additional carbon source. C/P ratios in a range of 5.1 to 28.7 did not induce glucoamylase production under the studied conditions.


2020 ◽  
Vol 117 (39) ◽  
pp. 24088-24095
Author(s):  
Laura L. Haynes ◽  
Bärbel Hönisch

The Paleocene–Eocene Thermal Maximum (PETM) (55.6 Mya) was a geologically rapid carbon-release event that is considered the closest natural analog to anthropogenic CO2 emissions. Recent work has used boron-based proxies in planktic foraminifera to characterize the extent of surface-ocean acidification that occurred during the event. However, seawater acidity alone provides an incomplete constraint on the nature and source of carbon release. Here, we apply previously undescribed culture calibrations for the B/Ca proxy in planktic foraminifera and use them to calculate relative changes in seawater-dissolved inorganic carbon (DIC) concentration, surmising that Pacific surface-ocean DIC increased by +1,010−646+1,415 µmol/kg during the peak-PETM. Making reasonable assumptions for the pre-PETM oceanic DIC inventory, we provide a fully data-driven estimate of the PETM carbon source. Our reconstruction yields a mean source carbon δ13C of −10‰ and a mean increase in the oceanic C inventory of +14,900 petagrams of carbon (PgC), pointing to volcanic CO2 emissions as the main carbon source responsible for PETM warming.


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