RESUMO
Fructooligosaccharides (FOS) are mixtures of oligosaccharides containing mono and disaccharides, therefore, the separation of these sugars results in purer products for human consumption and can be added to various food products (drinks, cookies and yogurt). The aim of this work was the purification of fructooligosaccharides from a mixture of sugars, obtained by enzymatic synthesis, containing fructooligosaccharides, glucose, fructose and sucrose using activated charcoal fixed bed column. Temperature and ethanol concentration effects were analyzed using a 2² central composite design. Good separation conditions were obtained through central composite design. The best separation coefficient between fructooligosaccharides and glucose (ES(fructoolig/gluc)) was 3.99 ± 0.07 and between fructose and fructooligosaccharides (ES(fructoolig/fruct)) was 2.89 ± 0.36 using ethanol 15% (v/v) as eluent, at 50°C. The final FOS purification degree and recovery were about 80% and 97.8%, respectively. The activated charcoal fixed bed columns were shown to be a good alternative for sugar separation, especially for rich mixtures of fructooligosaccharides.
Assuntos
Carvão Vegetal/química , Cromatografia/instrumentação , Cromatografia/métodos , Oligossacarídeos/isolamento & purificação , Adsorção , Carboidratos/química , Alimento Funcional , Humanos , Estrutura Molecular , Oligossacarídeos/químicaRESUMO
In this work, the agitation and aeration effects in the maximization of the beta-galactosidase production from Kluyveromyces marxianus CCT 7082 were investigated simultaneously, in relation to the volumetric enzyme activity and the productivity, as well as the analysis of the lactose consumption and production of glucose, and galactose of this process. Agitation and aeration effects were studied in a 2 L batch stirred reactor. A central composite design (2(2) trials plus three central points) was carried out. Agitation speed varied from 200 to 500 rpm and aeration rate from 0.5 to 1.5 vvm. It has been shown in this study that the volumetric enzyme production was strongly influenced by mixing conditions, while aeration was shown to be less significant. Linear models for activity and productivity due to agitation and aeration were obtained. The favorable condition was 500 rpm and 1.5 vvm, which lead to the best production of 17 U mL(-1) for enzymatic activity, 1.2 U mL(-1) h(-1) for productivity in 14 h of process, a cellular concentration of 11 mg mL(-1), and a 167.2 h(-1) volumetric oxygen transfer coefficient.
Assuntos
Reatores Biológicos/microbiologia , Biotecnologia/instrumentação , Kluyveromyces/enzimologia , beta-Galactosidase/biossíntese , Análise de Variância , Fermentação , Cinética , Propriedades de SuperfícieRESUMO
Inulinase belongs to an important class of enzymes as it can be used to produce high-fructose syrups by enzymatic hydrolysis of inulin and fructooligosaccharides, which has been used as functional food. This work aimed to carry out a partial characterization of the crude enzymatic extract of two different inulinases, obtained by solid-state fermentation (SSF) and submerged fermentation (SmF), using agroindustrial residues as substrates. The crude enzymatic extract obtained by SmF showed an optimal pH and temperature for hydrolytic activity of 4.5 and 55 degrees Celsius, respectively; and that obtained by SSF conducted to optimal pH and temperature of 5.0 and 55 degrees Celsius, respectively. Both enzymes presented high thermostability, with a D value of 230.4 h and 123.1 h for SmF and SSF, respectively. The inulinase produced by SmF showed highest stability at pH 4.4, while inulinase obtained by SSF was more stable at pH 4.8. The results showed that inulinase obtained by SmF is less susceptible to pH effect and the inulinase obtained by SSF is more resistant to higher temperatures.
Assuntos
Fermentação , Indústria Alimentícia , Imersão , Insulisina/metabolismo , Ativação Enzimática , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Insulisina/química , Insulisina/isolamento & purificação , Cinética , TemperaturaRESUMO
A mathematical model for an expanded bed column was developed to predict breakthrough curves for inulinase adsorption on Streamline SP ion-exchange adsorbent, using a crude fermentative broth with cells as the feedstock. The kinetics and mass transfer parameters were estimated using the PSO (particle swarm optimization) heuristic algorithm. The parameters were estimated for each expansion degree (ED) using three breakthrough curves at initial inulinase concentrations of 65.6UmL(-1). In sequence, the model parameters for an ED of 2.5 were validated using the breakthrough curve at an initial concentration of 114.4UmL(-1). The applicability of the validated model in process optimization was investigated, using the model as a process simulator and experimental design methodology to optimize the column and process efficiencies. The results demonstrated the usefulness of this methodology for expanded bed adsorption processes.
Assuntos
Cromatografia por Troca Iônica/métodos , Proteínas Fúngicas/química , Glicosídeo Hidrolases/química , Adsorção , Proteínas Fúngicas/isolamento & purificação , Glicosídeo Hidrolases/isolamento & purificação , Cinética , Kluyveromyces/enzimologia , Modelos TeóricosRESUMO
The accurate description of the kinetics and robust modeling of biotechnological processes can only be achieved by incorporating reliable methodologies to easily update the model when there are changes in operational conditions. The purpose of this work is to provide a systematic approach with which to perform model parameters screening and updating in biotechnological processes. Batch experiments are performed to develop a mechanistic model, considering the effect of temperature on the kinetics, and further experiments (batch fermentations using sugar cane molasses from a different harvest) are used to validate the effectiveness of screening before parameters updating. The reduction in the number of kinetic parameters to be re-estimated enabled by the screening procedure reduces significantly the complexity of the optimization, which makes the updating procedure to be significantly quicker, while resulting in accurate performance of the updated model.
Assuntos
Metabolismo dos Carboidratos/fisiologia , Etanol/metabolismo , Modelos Biológicos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Proliferação de Células , Simulação por Computador , Cinética , Controle de QualidadeRESUMO
Cultivations of Kluyveromyces marxianus var. bulgaricus ATCC 16045 were performed on both minimal and complex media using different carbon and nitrogen sources either in the presence or absence of aeration. The results collected were worked out and compared so as to provide a useful contribution to the optimization of inulinase production. Kinetics of extracellular inulinase release were similar on glucose, fructose, and sucrose. Inulinase was detected at basal level since the beginning of batch runs on these three carbon sources and overproduced after their depletion. The highest inulinase activity in minimal medium containing 10 g/l sucrose (6.4 IU/ml) was obtained at an initial (NH(4))(2)SO(4) concentration of 5 g/l, whereas it was reduced to about one fourth of this value and detected only at the beginning under nitrogen-limited conditions. The best sucrose concentrations for the enzyme production were 30 and 20 g/l in minimal and complex media, yielding 15.4 and 208 IU/ml, respectively. In general, the enzyme activity was much higher in complex than in minimal medium under all conditions. O(2)-enriched air neither improved inulinase production nor prevented ethanol formation.