Utjecaj organskih otapala na značajke slobodne i imobilizirane inulinaze, izolirane iz kvasca Kluyveromyces marxianus ATCC 16045

The aim of this work is to evaluate the effects of the butyl acetate concentration on the characteristics of free and immobilized inulinase from Kluyveromyces marxianus ATCC 16045. The mass fractions of organic solvent (OS) in sodium acetate buffer (0.1 M) were studied in the range from 25 to 70 %. The characteristics of both free and immobilized enzymes were not significantly affected by the OS mass fraction. The optimal temperature for the free enzyme was 55 °C at all OS mass fractions studied, whereas for the immobilized enzyme the optimum was 55 °C at 70 % of butyl acetate, and in the range from 50 to 60 °C at 25 and 50 % of OS. The optimum pH values, at all OS mass fractions, were 4.8 and 4.4 for the free and immobilized enzymes, respectively. The immobilized enzyme showed more stability at 50 °C and pH=4.8 for the whole range of OS mass fractions, since its stability was improved about 3 times. The kinetics parameters were calculated using Lineweaver-Burk plots. For the free enzyme, the vmax values were 12.5, 58.5 and 37.6 U/mL and the Km values 17.5, 280.7 and 210.4 mM at butyl acetate mass fractions of 25, 50 and 70 %, respectively. Similarly, for the immobilized enzyme, the vmax values were 38.9, 59.5 and 72.5 U/mL and the Km values 3.1, 5.4 and 14.0 mM at the same butyl acetate mass fractions, respectively.Svrha je ovoga rada bila procijeniti utjecaj koncentracije butilnog acetata na značajke slobodne i imobilizirane inulinaze, izolirane iz kvasca Kluyveromyces marxianus ATCC 16045. Upotrijebljeni su maseni udjeli organskih otapala u acetatnom puferu od 25 do 70 %, te je utvrđeno da maseni udjeli otapala nije bitno utjecao na značajke enzima, Optimalna je temperatura za aktivnost slobodnog enzima bila 55 °C pri svim udjelima otapala, a za imobilizirani enzim 55 °C uz dodataka 70 % butilnog acetata, te u rasponu od 50 do 60 °C uz dodatak 25 i 50 % otapala. Utvrđena je optimalna pH-vrijednost od 4,8 za slobodni, te 4,4 za imobilizirani enzim. Stabilnost imobiliziranog enzima bila je trostruko veća pri 50 °C i pH=4,8, pri svim udjelima otapala. Određeni su kinetički parametri primjenom dijagrama Lineweaver-Burk, te utvrđene ove vrijednosti za slobodni enzim: vmax od 12,5 U/mL pri 25 %, 58,5 U/mL pri 50 % i 37,6 U/mL pri 70 % otapala, te Km od 17,5 mM pri 25 %, 280,7 mM pri 50 %, te 210,4 mM pri 70 % otapala. Vrijednosti za imobilizirani enzim iznosile su: vmax od 38,9 U/mL pri 25 %, 59,5 U/mL pri 50 % i 72,5 U/mL pri 70 % otapala, a Km od 3,1 mM pri 25 %, 5,4 mM pri 50 % i 14,0 mM pri 70 % butilnog acetata

Produção de biogás por digestão em fase sólida de cama de frango.

RESUMO: A cama de frango é um resíduo da atividade avícola, que é gerado em grandes quantidades, e quando mal manuseado tem elevado potencial poluidor. No entanto, é possível aproveitar este resíduo para geração de biogás, contudo este substrato apresenta desafios devido a baixa umidade e composição química. Diante deste contexto, a digestão em fase sólida se destaca como um processo promissor pelo fato de evitar o manejo ou póstratamento da água derivada do processo. O objetivo do presente estudo foi avaliar a eficiência da produção de biogás de cama de frango em um reator anaeróbio de fase sólida (RDFS) operado em batelada. Ao realizar o processo de digestão em fase sólida, verificouse que este sistema apresentou um rendimento de biogás de 90,30 mLNbiogás.gSVadic -1 ,quando comparado ao valor de referência do teste do potencial bioquímico de biogás que foi de 281 mLNbiogás.gSVadic -1 , a eficiência foi de 32 % após 30 dias de digestão. No entanto, o teor de sólidos totais que o RDFS pode operar é de 30 %, enquanto que a digestão úmida a concentração de sólidos totais é em média de 10%. Neste caso utilizando o RDFS estaremos economizando líquido para diluição do substrato, e este é um sistema robusto, de fácil monitoramento que pode ser utilizado pelos avicultores, podendo ainda ser otimizado para melhoria do sistema e assim aumentar a eficiência de produção de biogás. ABSTRACT: The poultry litter is a residue from poultry activity, which is generated in large quantities and, when poorly handled, presents a high polluting potential. It is possible to take advantage of this residue to generate biogas, however this substrate consists in a challenging material due to its humidity and chemical composition. In this context, solid-state digestion stands out as a promising process because it prevents the handling or post-treatment of water derived from the process. The goal of the present study was to evaluate the efficiency of production of poultry litter biogas in a solid phase anaerobic reactor operated in batch. When carrying out the solid phase digestion process, it was verified that this system presented a biogas production of 90,30 mLNbiogas.gSVadd -1 . When comparing this to the reference value of the biochemical potential of biogas test, which is 281 mLNbiogas.gSVadd -1 , the efficiency attained was 32% at the 30-day of digestion However, the total solids content that the RDFS can operate is 30%, while the wet digestion at the total solids concentration is on average 10%. In this case using the RDFS we will be saving liquid for dilution of the substrate, and this is a robust system, easy to monitor that can be used by poultry farmers and can be optimized for system improvement and thus increase biogas production efficiency

Atmospheric Muon Flux at Sea Level, Underground, and Underwater

The vertical sea-level muon spectrum at energies above 1 GeV and the underground/underwater muon intensities at depths up to 18 km w.e. are calculated. The results are particularly collated with a great body of the ground-level, underground, and underwater muon data. In the hadron-cascade calculations, the growth with energy of inelastic cross sections and pion, kaon, and nucleon generation in pion-nucleus collisions are taken into account. For evaluating the prompt muon contribution to the muon flux, we apply two phenomenological approaches to the charm production problem: the recombination quark-parton model and the quark-gluon string model. To solve the muon transport equation at large depths of homogeneous medium, a semi-analytical method is used. The simple fitting formulas describing our numerical results are given. Our analysis shows that, at depths up to 6-7 km w. e., essentially all underground data on the muon intensity correlate with each other and with predicted depth-intensity relation for conventional muons to within 10%. However, the high-energy sea-level data as well as the data at large depths are contradictory and cannot be quantitatively decribed by a single nuclear-cascade model.Comment: 47 pages, REVTeX, 15 EPS figures included; recent experimental data and references added, typos correcte

Final report on the search for neutrinoless double-β decay of 76Ge from the Gotthard underground experiment

We report here on the final results of a search for Ge-76 double-beta decay conducted in the Gotthard underground laboratory. The detector consists of an array of eight high-purity natural germanium crystals totaling 1095 cm^3 fiducial volume. The accumulated data set represents a sensitivity of 10.0 kg yr. No indication of neutrinoless double-beta decay was found. The measured half-life limits are T1/2(0+ --> 0+) > 6.0(3.3) x 10^(23) yr for the transition to the ground state and T1/2(0+ --> 2+) > 1.4(0.65) x 10^(23) yr for the transition to the first excited state at 68% (90%) C.L. From these results we derive an upper limit for the Majorana mass of the neutrino in the range of 1.8 to 6.7 eV depending on matrix-element calculations. The same results allow limits to be set for the right-handed-current parameters: < 2.2 x 10^(-8)

New limit on neutrinoless double β decay in ^(136)Xe with a time projection chamber

A xenon time projection chamber with an active volume of 207 L has been built to study neutrinoless double β decay in ^(136)Xe. Data were taken in the Gotthard Underground Laboratory, with 5 atm of xenon enriched to 62.5% in ^(136)Xe. From 3380 h of data, no evidence has been found for the 0ν 0^(+)→0^(+) transition. Half-life limits of T_(1/2)^(0ν)>2.5(4.9)×10^(23) yr in the mass-mechanism mode and T_(1/2)^(0ν)>1.7(3.2)×10^(23) yr in the right-handed-current mode, at the 90(68)% C.L., were derived. An upper limit for the Majorana neutrino mass parameter was deduced

Search for neutrinoless double-beta decay in 136-Xe with a time projection chamber

A xenon time projection chamber (TPC) with an active volume of 180 liters has been built to study neutrinoless double-beta decay in Xe-136. The experiment was performed in the Gotthard Underground Laboratory, with 5 atm of xenon enriched to 62.5% in Xe-136. The experimental details, background considerations, detector performance, and data analysis are discussed. From 6830 h of data, no evidence has been found for the 0nu 0+-->0+ transition. Half-life limits of T1/2(0nu) > 3.4(6.4) X 10^(23) yr in the mass mechanism mode, and T1/2(0nu) > 2.6(4.9) X 10^23 yr in the right-handed currents mode, at the 90(68)% C.L., were derived, corresponding to an upper limit on the Majorana neutrino mass parameter [m(nu)] of about 2.8 eV. Limits on two-neutrino double-beta decay of T1/2(2nu) /2 > 2. 1 X 10^(20) yr, and on neutrinoless double-beta decay with Majoron emission of T1/2(0nuchi) > 4.9 X 10^(21) yr, both at 90% C.L., were also derived. Accordingly, a limit on the effective Majoron-neutrino coupling parameter of [g(M)] < 2.4 X 10^(-4) was deduced

Sp6 and Sp8 transcription factors control AER formation and dorsal-ventral patterning in limb development

The formation and maintenance of the apical ectodermal ridge (AER) is critical for the outgrowth and patterning of the vertebrate limb. The induction of the AER is a complex process that relies on integrated interactions among the Fgf, Wnt, and Bmp signaling pathways that operate within the ectoderm and between the ectoderm and the mesoderm of the early limb bud. The transcription factors Sp6 and Sp8 are expressed in the limb ectoderm and AER during limb development. Sp6 mutant mice display a mild syndactyly phenotype while Sp8 mutants exhibit severe limb truncations. Both mutants show defects in AER maturation and in dorsal-ventral patterning. To gain further insights into the role Sp6 and Sp8 play in limb development, we have produced mice lacking both Sp6 and Sp8 activity in the limb ectoderm. Remarkably, the elimination or significant reduction in Sp6;Sp8 gene dosage leads to tetra-amelia; initial budding occurs, but neither Fgf8 nor En1 are activated. Mutants bearing a single functional allele of Sp8 (Sp6-/-;Sp8+/-) exhibit a split-hand/foot malformation phenotype with double dorsal digit tips probably due to an irregular and immature AER that is not maintained in the center of the bud and on the abnormal expansion of Wnt7a expression to the ventral ectoderm. Our data are compatible with Sp6 and Sp8 working together and in a dose-dependent manner as indispensable mediators of Wnt/βcatenin and Bmp signaling in the limb ectoderm. We suggest that the function of these factors links proximal-distal and dorsal-ventral patterning