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

Extraction of rice bran oil using supercritical CO2 combined with ultrasound

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORRice bran oil (RBO) contains oryzanol and tocopherols. Its recovery was performed using conventional techniques with toxic solvents that leave residues in the final product. Supercritical fluid extraction (SFE) has been used, obtaining high global yields352785794CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIOR552229/2011-32013/02203-6sem informaçã

Variabilidade química de compostos orgânicos voláteis e semivoláteis de populações nativas de Maytenus ilicifolia

This work is focused on the chemical distribution of volatile and semi-volatile compounds of 18 native populations of Maytenus ilicifolia collected all over Brazil. The extracts of bulk samples (30 plants) of each population were obtained by supercritical CO2 extraction technique, and analyzed by GC/MS. The quantification of compounds (phytol, squalene, vitamin E, limonene, stigmasterol, friedelan-3-ol, friedelin, fridelan-3-one, palmitic acid and geranyl acetate) showed significant variations within the different populations, which could be related tom microclimate characteristics

Inactivation of Listeria monocytogenes using supercritical carbon dioxide in a high-pressure variable-volume reactor

AbstractThis work evaluates the inactivation of Listeria monocytogenes through the use of supercritical carbon dioxide. For this purpose, the experimental design methodology was employed as a tool to assess the effects of temperature, depressurization rate, pressure cycling and the mass ratio of cell suspension to CO2. It was observed that the depressurization rate and mass of cell suspension to CO2 ratio were statistically significant and inactivation kinetics was verified to be of first-order. It was also observed that the inactivation increased with increasing depressurization rates in the range of 6–12 MPa min−1, keeping nearly constant above the upper value. The decimal reduction times ranged from 15.38 to 20.41 min. Results obtained in this work may be quite useful to the food industry committed to microorganism inactivation using the innovative supercritical carbon dioxide technology

Synthesis of eugenyl acetate by enzymatic reactions in supercritical carbon dioxide

Supercritical carbon dioxide (SC-CO2) as reaction medium has gained attention in the production of terpenic esters catalyzed by lipases. Therefore, this work investigated the production of eugenyl acetate by esterification of eugenol and acetic anhydride in SC-CO2 using two commercial lipases (Lipozyme 435 and Novozym 435) as catalysts. The influence of enzyme concentration (1⿿10% weight/weight), substrates⿿ molar ratio (1:1 to 5:1), temperature (40⿿60 °C) and pressure of SC-CO2 (10⿿30 MPa) on the esterification rate (X; %) and specific productivity (SP; kg of product/kg of catalyst x hour) were evaluated. A home-made high-pressure stirred-batch reactor (100 ml) was used in the experiments. The use of Novozym 435 achieved higher conversion and specific productivity of eugenyl acetate than Lipozyme 435. An excess of acetic anhydride (5:1 M/M) and high enzyme concentration (10%) achieved higher esterification rates than the lowest conditions (1% and 1:1 M/M). The optimal temperatures and pressure for the synthesis of eugenyl acetate in SC-CO2 were 50 and 60 °C at 10 MPa, respectively. The phase behavior of the reaction system and the synthesis in organic medium were also studied. Kinetic experiments performed at 40, 50 and 60 °C indicated that the reaction follows the simple Ping-Pong Bi-Bi mechanism and the affinity of acetic anhydride to enzyme was larger than that of eugenol11419CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP142373/2013-32952/20112013/02203-6; 2015/11932-7; 2009/54137-