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71.
Comparison of different methods for the detoxification of lignocellulose hydrolyzates of spruce 总被引:9,自引:0,他引:9
Simona Larsson Anders Reimann Nils-Olof Nilvebrant Leif J. Jönsson 《Applied biochemistry and biotechnology》1999,77(1-3):91-103
This study describes different detoxification methods to improve both cell growth and ethanol production by Baker's yeast,
Saccharomyces cerevisiae. A dilute-acid hydrolyzate of spruce was used for the all detoxification methods tested. The changes in the concentrations
of fermentable sugars and three groups of inhibitory compounds—aliphatic acids, furan derivatives, and phenolic compounds—were
determined and the fermentability of the detoxified hydrolyzate was assayed. The applied detoxification methods included:
treatment with alkali (sodium hydroxide or calcium hydroxide); treatment with sulfite (0.1% [w/v] or 1% [w/v] at pH 5.5 or
10); evaporation of 10% or 90% of the initial volume; anion exchange (at pH 5.5 or 10); enzymatic detoxification with the
phenoloxidase laccase; and detoxification with the filamentous fungus Trichoderma reesei. An ion exchange at pH 5.5 or 10, treatment with laccase, treatment with calcium hydroxide, and treatment with T. reesei were the most efficient detoxification methods. Evaporation of 10% of the initial volume and treatment with 0.1% sulfite
were the least efficient detoxification methods. Treatment with laccase was the only detoxification method that specifically
removed only one group of the inhibitors, namely phenolic compounds. Anion exchange at pH 10 was the most efficient method
for removing all three major groups of inhibitory compounds; however, it also resulted in loss of fermentable sugars. 相似文献
72.
73.
Peter Reimann 《Journal of statistical physics》1996,82(5-6):1467-1501
We study one-dimensional single-humped maps near the boundary crisis at fully developed chaos in the presence of additive weak Gaussian white noise. By means of a new perturbation-like method the quasi-invariant density is calculated from the invariant density at the crisis in the absence of noise. In the precritical regime, where the deterministic map may show periodic windows, a necessary and sufficient condition for the validity of this method is derived. From the quasi-invariant density we determine the escape rate, which has the form of a scaling law and compares excellently with results from numerical simulations. We find that deterministic transient chaos is stabilized by weak noise whenever the maximum of the map is of orderz>1. Finally, we extend our method to more general maps near a boundary crisis and to multiplicative as well as colored weak Gaussian noise. Within this extended class of noises and for single-humped maps with any fixed orderz>0 of the maximum, in the scaling law for the escape rate both the critical exponents and the scaling function are universal. 相似文献
74.
R. Eichhorn A. Ros J. Regtmeier T. Tu Duong P. Reimann D. Anselmetti 《The European physical journal. Special topics》2007,143(1):159-164
We report on a paradoxical migration mechanism in a microstructured
lab-on-a-chip environment.
The phenomenon is based on a subtle interplay between
Brownian motion (thermal noise), a periodic and symmetric microstructure,
and a biased AC electric field.
The resulting non-linear dynamics
far from thermal equilibrium gives rise to absolute negative
mobility, i.e. a migrational transport, which is – both for
negative and positive bias – always opposite to the net acting
force, in good agreement between experiment and theory. 相似文献
75.
76.
Single-cycle terahertz (THz) transients in the frequency range 0.3-7 THz with electric-field amplitudes of more than 400 kV/cm are generated by four-wave mixing of the fundamental and the second harmonic of 25 fs pulses from a Ti:sapphire amplifier in ionized air. These transients are fully characterized by electro-optic sampling with ZnTe and GaP crystals. One can tune the center frequency of the THz transients by varying the length of the incident pulse. The electric-field amplitude increases linearly with the incident pulse energy. 相似文献
77.
Michael?CowlingEmail author Filippo?De?Mari Adam?Korányi Hans?Martin?Reimann 《Geometriae Dedicata》2005,111(1):65-86
When
the action of the conformal group O(1, n+1) on
may be characterized in simple differential geometric terms, even locally: a theorem of Liouville states that a C4 map between domains
and
in
whose differential is a (variable) multiple of a (variable) isometry at each point of
is the restriction to
of a transformation x g·x, for some g in O(1,n+1). In this paper, we consider the problem of characterizing the action of a more general semisimple Lie group G on the space G/P, where P is a minimal parabolic subgroup. 相似文献
78.
Dr. Hans Martin Reimann 《Mathematische Zeitschrift》1972,129(2):163-171
Ohne Zusammenfassung 相似文献
79.
Ohne Zusammenfassung 相似文献
80.