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71.
A. M. Verbovetsky R. Vitolo P. Kersten I. S. Krasil’shchik 《Theoretical and Mathematical Physics》2012,171(2):600-615
We consider a third-order generalized Monge-Ampère equation uyyy ? u xxy 2 + uxxxuxyy = 0, which is closely related to the associativity equation in two-dimensional topological field theory. We describe all integrable structures related to it: Hamiltonian, symplectic, and also recursion operators. We construct infinite hierarchies of symmetries and conservation laws. 相似文献
72.
We studied the effect of reactor filling time (T) (3-5 h), initial mass of inoculum (M) (1000-2100 g), and exponential time decay constant for the substrate feed rate (K) (0.6-1.6 h-1) on ethanol production by Saccharomyces cerevisiae grown in sugarcane blackstrap molasses through a fed-batch culture. The highest ethanol productivity (16.9 g/[L x h]) occurred at T = 3 h, K = 1.6 h-1, and M = 1300 g. In addition, productivity was affected by both M (for T = 3 and 4 h) and K (for T = 3 h) and varied inversely with T under any value fixed for M and K. By the quadratic regression multivariable analysis method, equations were determined to estimate ethanol yield and productivity as function of the variables studied (T, K, and M). 相似文献
73.
Yan Xu Michele Vitolo Cristina Northfleet de Albuquerque Adalberto Pessoa Jr. 《Applied biochemistry and biotechnology》2003,108(1-3):853-865
To improve the selectivity of glucose-6-phosphate dehydrogenase (G6PDH) extraction by an aqueous two-phase system, a simple
and inexpensive affinity aqueous two-phase system using unbound reactive triazine dyes as ligands was introduced. In a polyethylene
glycol (PEG)/hydroxypropyl starch (PES) system, the unbound free triazine dyes, Cibacron Blue F3GA and Procion Red HE3B, partitioned
unevenly in the top PEG-rich phase and thus showed an affinity effect on G6PDH, but no influence on hexokinase. The various
parameters investigated were pH of the system, buffers, molecular weight of PEG, and ligand type and concentration. A two-step
affinity extraction process was established for the purification of G6PDH from baker’s yeast. The total yield of G6PDH was
66.9% and purification factor was 2.35. 相似文献
74.
The conversion of glucose and fructose into gluconic acid (GA) and sorbitol (SOR) was conducted in a batch reactor with free
(CTAB-treated or not) or immobilized cells of Zymomonas mobilis. High yields (more than 90%) of gluconic acid and sorbitol were attained at initial substrate concentration of 600 g/L (glucose
plus fructose at 1:1 ratio), using cells with glucose-fructose-oxidoreductase activity of 75 U/L. The concentration of the
products varied hyperbolically with time according to the equations (GA)=t(GA)max/(WGA +t), (SOR)=t (SOR)max/(WSor+t), vGA=[WGA (GA)max]/(WGA+t)2 and VSOR=[WSOR (SOR)max]/(WSOR+t)2. Taking the test carried out with free CTAB-treated cells as an example, the constant parameters were (GA)max= 541 g/L, (SOR)max=552 g/L, WGA=4.8h, WSOR=4.9h, υGA=112.7 g/L· and υSOR=112.7 g/L·. 相似文献
75.
This article aims at the evaluation of the catalytic performance of glucose oxidase (GO) (EC.1.1.3.4) for the glucose/gluconic acid conversion in the ultrafiltration cell type membrane reactor (MB-CSTR). The reactor was coupled with a Millipore ultrafiltration-membrane (cutoff of 100 kDa) and operated for 24 h under agitation of 100 rpm, pH 5.5, and 30 degrees C. The experimental conditions varied were the glucose concentration (2.5, 5.0, 10.0, 20.0, and 40.0 mM), the feeding rate (0.5, 1.0, 3.0, and 6.0/h), dissolved oxygen (8.0 and 16.0 mg/L), GO concentration (2.5, 5.0, 10.0, and 20.0 U(GO)/mL), and the glucose oxidase/catalase activity ratio (U(GO)/U(CAT))(1:0, 1:10, 1:20, and 1:30). A conversion yield of 80% and specific reaction rate of 40 x 10(-4) mmol/h x U(GO) were attained when the process was carried out under the following conditions: D =3.0/h, dissolved oxygen =16.0 mg/L, [G] =40 mM, and (U(GO)/U(CAT)) =1:20. A simplified model for explaining the inhibition of GO activity by hydrogen peroxide, formed during the glucose/gluconic acid conversion, was presented. 相似文献
76.
Multienzymatic conversion of sucrose into fructose and gluconic acid was studied through fed-batch and continuous (in a membrane reactor) processes. The law of substrate addition (sucrose or glucose) for the fed-batch process which led to a yield superior to 80% was the decreasing linear type, whose feeding rate (?; L/h) was calculated through the equation: ? = ?o ? k.t, where ?o (initial feeding rate, L/h), k (linear addition constant, L/h 2), and t (reaction time, h). In the continuous process, the yield of conversion of sucrose (Y) was superior to 70% under the following conditions: dilution rate?=?0.33 h?1, total duration of 15 h, pH 5.0, 37 °C and initial sucrose concentration of 64 g/L (Y?=?92%), 100 g/L (Y?=?83%), or 150 g/L (Y?=?76%). 相似文献