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71.
Constanti Magda Giralt Jaume Bordons Albert Norris Paul R. 《Applied biochemistry and biotechnology》1992,(1):767-776
The growth and oxygen consumption of a variety of thermophilic, acidophilic bacteria in the presence of thiophene-2-carboxylate
(T2C) and dibenzothiophene (DBT) have been determined. T2C was extremely toxic to the acidophiles in comparison with neutrophiles,
but appeared to be degraded by a heterotrophicSulfolobus- like thermophile. DBT proved to be unstable at high temperatures, even in the absence of bacteria, and was not a substrate for
the thermophiles. 相似文献
72.
Cruz A. J. G. Araujo M. L. G. C. Giordano R. C. Hokka C. O. 《Applied biochemistry and biotechnology》1998,(1):579-592
Cephalosporin C production process withCephalosporium acremonium ATCC 48272 in synthetic medium was investigated and the experimental results allowed the development of a mathematical model
describing the process behavior. The model was able to explain fairly well the diauxic phenomenon, higher growth rate during
the glucose-consumption phase, and the production occurring only in the sucrose-consumption phase.
Moreover, the process was simulated utilizing the neural-networks technique. Two feed-forward neural-networks with one hidden
layer were employed. Both models, phenomenological and neural-networks based, satisfactorily describe the bioprocess. The
difficulties in determining kinetic parameters are avoided when neural networks are utilized. 相似文献
73.
Shetty Kalidas Korus roger A. Crawford Dom L. 《Applied biochemistry and biotechnology》1989,(1):825-843
Glycine max was used as a model plant cell suspension culture to establish relationships among growth kinetics, phenolics production,
elicitor action, and peroxidase activity. Timing of elictor addition through monitoring of peroxidase provided an excellent
means of optimizing yields of phenolics and reduced the time span during which phenolics were formed, negating the need for
a secondary production medium. We have also determined that calcium and other cellular effectors like polyamines and organic
osmolytes, when used in conjunction with elicitors, enhance phenolics production. Calcium directly enhanced elicitation, whereas
polyamines and other osmolytes such as glycerol and proline extended cell viability. The study also demonstrated potential
for enhancing secondary metabolite production by a combination of elicitation, cell viability stabilizers, and by addition
of nutrients at the time of elicitation. 相似文献
74.
Rivard C. J. Himmel M. E. Vinzant T. B. Adney W. S. Wyman C. E. Grohmann K. 《Applied biochemistry and biotechnology》1989,(1):461-478
Economic evaluations of the capital costs for anaerobic digestion systems for gas production show that the reactor is a significant
cost component. The successful application of high solids digestion of processed MSW (e.g., greater than 10% solids within
the digester) would allow a decrease in reactor volume with maintenance of relatively high gas production rates. However,
high solids slurries do not mix well in conventional stirred tank reactors. A horizontal shaft, hydraulically driven reactor
was designed and fabricated to test the anaerobic digestion of high solids concentrations. Digester performance was evaluated
as a function of experimental parameters such as nutrient requirements, feeding rates, pH control, and agitator design/ rotation
speed; horsepower of mixing was also evaluated for the reactor. Several startup protocols were examined to obtain a biologically
stable anaerobic fermentation at high solids levels. 相似文献
75.
Lamb pregastric lipase was purified from a commercial source using delipidation, solubilization with KSCN, acid-precipitation, pepsin-digestion, affinity chromatography with agarose-Cibacron Blue F3GA, gel filtration, and elution from a native 10% (w/v) polyacrylamide gel. The enzyme had a single subunit of 68,000 Da with maximum esterase activity when measured at pH 6.0 and 30 degrees C. The enzyme preferentially hydrolyzed short- and medium-chain (C4, C6, and C8) synthetic esters and short-chain (C4 and C6) monoacid triglycerides. The NH2-terminal sequence demonstrated high homology with gastric and lingual lipases. 相似文献
76.
Shi Nian-Qing Prahl Kristine Hendrick Jim Cruz Jose Lu Ping Cho Jae-Yong Jones Sharon Jeffries Thomas 《Applied biochemistry and biotechnology》2000,84(1-9):201-216
Pichia stipitis CBS 6054 will grow on d-xylose, d-arabinose, and l-arabinose. d-Xylose and l-arabinose are abundant in seed hulls of maize, and their utilization is important in processing grain residues. To elucidate
the degradation pathway for l-arabinose, we obtained a mutant, FPL-MY30, that was unable to grow on d-xylose and l-arabinose but that could grow on d-arabinitol. Activity assays of oxidoreductase and pentulokinase enzymes involved in d-xylose, d-arabinose, and l-arabinose pathways indicated that FPL-MY30 is deficient in d-xylitol dehydrogenase (D-XDH), d- and l-arabinitol dehydrogenases, and d-ribitol dehydrogenase. Transforming FPL-MY30 with a gene for xylitol dehydrogenase (PsXYL2), which was cloned from CBS 6054 (Gen Bank AF127801), restored the D-XDH activity and the capacity for FPL-MY30 to grow on
l-arabinose. This suggested that FPL-MY30 is critically deficient in XYL2 and that the d-xylose and l-arabinose metabolic pathways have xylitolas a common intermediate. The capacity for FPL-MY30 to grow on d-arabinitol could proceed through d-ribulose. 相似文献
77.
Converse A. O. Kwarteng I. K. Grethlein H. E. Ooshima H. 《Applied biochemistry and biotechnology》1989,(1):63-78
The results of an experimental study of the acid hydrolysis of hardwood are presented in the form of values for the three
parameters, activation energy, power on the acid concentration, and pre-exponen-tial factor, of the first order kinetic constants
for each of the following reaction participants: xylan remaining, glucan remaining, xylose formed, and xylose decomposed.
These are used as a base for a quantitative theory to predict the temperature, time, and acid concentrations needed for effective
pretreatment of the substrate for subsequent enzymatic hydrolysis of the glucan. This theory is based on the assumption that
successful pretreatment requires >90% removal of the xylan, <10% removal of the glucan, and >80% xylose yield. This theory
is compared with selected published data. 相似文献
78.
Er~(3 ),Ho~(3 )和Tm~(3 )在硫氧化钆中的余辉发光 总被引:4,自引:0,他引:4
非放射性长余辉磷光粉作为美化和清洁光源在发光陶瓷、交通安全标志、紧急突发事件的照明设施、工艺美术涂料等众多领域得到越来越广泛的应用,引起人们的重视.到目前为止,文献报道的稀土长余辉磷光体的激活离子主要有铕离子(Eu3+和Eu2+[1-4]、三价铈离子(Ce3+)[5]、三价铽离子(Tb3+)[6]、三价镨离子(Pr3+)[7]、三价钐离子(Sm3+)[8].Ho3+,Er3+,Tm3+等稀土离子作为红外上转换发光材料的激活离子[9~12],而关于它们的长余辉发光的报道极少.最近,雷炳富等在Tm3+离子[13]激活的硫氧化钇体系中发现了长余辉发光.在此,我们通过高温固相法合成了Er3+,Ho3+和Tm3+掺杂的硫氧化钆长余辉磷光粉,观察到该体系中迄今未见文献报道的Er3+,Ho3+和Tm3+离子的长余辉发光. 相似文献
79.
80.
Nidetzky Bernd Griessler Richard Weinhausel Andreas Haltrich Dietmar Kulbe Klaus D. 《Applied biochemistry and biotechnology》1997,(1):159-172
Some important process properties of α-l,4-D-ghican phosphorylases isolated from the bacteriumCorynebacterium callunae and potato tubers (Solatium tuberosum) were compared. Apart from minor differences in their stability and specificity (represented by the maximum degree of maltodextrin
conversion) and a 10-fold higher affinity of the plant phosphorylase for maltodextrin (K
M of 1.3 g/L at 300 mM of orthophosphate), the performances of both enzymes in a continuous ultrafiltration membrane reactor
were almost identical. Product synthesis was carried out over a time course of 300–400 h in the presence or absence of auxiliary
pullulanase (increasing the accessibility of the glucan substrate for phosphorolytic attack up to 15–20%). The effect of varied
dilution rate and reaction temperature on the resulting productivities was quantitated, and a maximum operational temperature
of 40°C was identified. 相似文献