ABSTRACT
ABSTRACT L-asparaginase (EC 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in L-aspartic acid and ammonium. This enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. It can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma), and has been a pivotal agent in chemotherapy protocols from around 30 years. Also, other important application is in food industry, by using the properties of this enzyme to reduce acrylamide levels in commercial fried foods, maintaining their characteristics (color, flavor, texture, security, etc.) Actually, L-asparaginase catalyzes the hydrolysis of L-asparagine, not allowing the reaction of reducing sugars with this aminoacid for the generation of acrylamide. Currently, production of L-asparaginase is mainly based in biotechnological production by using some bacteria. However, industrial production also needs research work aiming to obtain better production yields, as well as novel process by applying different microorganisms to increase the range of applications of the produced enzyme. Within this context, this mini-review presents L-asparaginase applications, production by different microorganisms and some limitations, current investigations, as well as some challenges to be achieved for profitable industrial production.
Subject(s)
Humans , Animals , Asparaginase/biosynthesis , Industrial Microbiology , Drug Industry , Fermentation , Antineoplastic Agents , Asparaginase , Food IndustryABSTRACT
ABSTRACT L-asparaginase (EC 3.5.1.1) is an enzyme that catalysis mainly the asparagine hydrolysis in L-aspartic acid and ammonium. This enzyme is presented in different organisms, such as microorganisms, vegetal, and some animals, including certain rodent's serum, but not unveiled in humans. It can be used as important chemotherapeutic agent for the treatment of a variety of lymphoproliferative disorders and lymphomas (particularly acute lymphoblastic leukemia (ALL) and Hodgkin's lymphoma), and has been a pivotal agent in chemotherapy protocols from around 30 years. Also, other important application is in food industry, by using the properties of this enzyme to reduce acrylamide levels in commercial fried foods, maintaining their characteristics (color, flavor, texture, security, etc.) Actually, L-asparaginase catalyzes the hydrolysis of L-asparagine, not allowing the reaction of reducing sugars with this aminoacid for the generation of acrylamide. Currently, production of L-asparaginase is mainly based in biotechnological production by using some bacteria. However, industrial production also needs research work aiming to obtain better production yields, as well as novel process by applying different microorganisms to increase the range of applications of the produced enzyme. Within this context, this mini-review presents L-asparaginase applications, production by different microorganisms and some limitations, current investigations, as well as some challenges to be achieved for profitable industrial production.
ABSTRACT
The use of hemicellulosic hydrolysates in bioprocesses requires supplementation as to ensure the best fermentative performance of microorganisms. However, in light of conflicting data in the literature, it is necessary to establish an inexpensive and applicable medium for the development of bioprocesses. This paper evaluates the fermentative performance of Scheffersomyces (Pichia) stipitis and Candida guilliermondii growth in sugarcane bagasse hemicellulosic hydrolysate supplemented with different nitrogen sources including rice bran extract, an important by-product of agroindustry and source of vitamins and amino acids. Experiments were carried out with hydrolysate supplemented with rice bran extract and (NH4)2SO4; peptone and yeast extract; (NH4)2SO4, peptone and yeast extract and non-supplemented hydrolysate as a control. S. stipitis produced only ethanol, while C. guilliermondii produced xylitol as the main product and ethanol as by-product. Maximum ethanol production by S. stipitis was observed when sugarcane bagasse hemicellulosic hydrolysate was supplemented with (NH4)2SO4, peptone and yeast extract. Differently, the maximum xylitol formation by C. guilliermondii was obtained by employing hydrolysate supplemented with (NH4)2SO4 and rice bran extract. Together, these findings indicate that: a) for both yeasts (NH4)2SO4 was required as an inorganic nitrogen source to supplement sugarcane bagasse hydrolysate; b) for S. stipitis, sugarcane hemicellulosic hydrolysate must be supplemented with peptone and yeast extract as organic nitrogen source; and: c) for C. guilliermondii, it must be supplemented with rice bran extract. The present study designed a fermentation medium employing hemicellulosic hydrolysate and provides a basis for studies about value-added products as ethanol and xylitol from lignocellulosic materials.
Subject(s)
Candida/metabolism , Cellulose/metabolism , Culture Media/chemistry , Oryza , Plant Extracts , Pichia/metabolism , Saccharum/metabolism , Candida/growth & development , Ethanol/metabolism , Pichia/growth & development , Xylitol/metabolismABSTRACT
O consumo de álcool e outras drogas é cada vez mais frequente entre adolescentes. O estudo objetivou identificar a percepção dos adolescentes acerca do consumo de álcool e outras drogas no âmbito familiar. Neste estudo qualitativo empregou-se o grupo focal para a coleta de dados. Os cinco colaboradores, com idade entre 12 e 15 anos, frequentavam um centro de assistência social, vinculado a uma instituição de ensino superior, de um município do Médio Vale do Paraíba Paulista. Os relatos expressaram a percepção dos adolescentes, suas contradições e sentimentos em relação ao tema e essa percepção pautou-se em hábitos dos familiares.
El consumo de alcohol y otras drogas es cada vez más común entre los adolescentes. El objetivo del estudio fue identificar las percepciones de los adolescentes sobre el alcohol y otras drogas en la familia. En ese estudio cualitativo, grupos focales fueron usados para recoger los datos. Los cinco empleados de entre 12 y 15 años eran clientes de un centro de servicios sociales vinculado a una institución de educación superior en un municipio en el Valle Medio del Paraíba Paulista. Los informes expresaron la percepción de los adolescentes, sus contradicciones y sentimientos sobre el tema y esta percepción se basaba en los hábitos de los miembros de la familia.
The consumption of alcohol and other drugs is increasingly frequent among adolescents. The study aimed to identify the perception of adolescents about the consumption of alcohol and other drugs within the family. In this qualitative study, focus groups were used to collect data. The five collaborators, between 12 and 15 years old, attended a social service center affiliated with a higher education institution in a city in the Médio Vale do Paraíba Paulista. The reports expressed the adolescents' perception, its contradictions and feelings on the theme and this perception was based on family members' habits.
Subject(s)
Humans , Male , Female , Adolescent , Alcoholism , Family , Perception , Substance-Related DisordersABSTRACT
The aim of this work was to evaluate the effect of xylitol on J774A.1 macrophage adhesion. Adhesion consisted of a three-hour interval, at room temperature, followed by washing and cell incubation at 37ºC/5 percent CO2/ 48h. Xylitol was used to treat the cells either before (for 24h) or after the cell incubation (for 48h) at 5 percent as final concentration in both the situations. It was found that xylitol was effective in preventing the adhesion in both the conditions in spite of the former being 100-fold greater and significant (p < 0.001). The results pointed to an important xylitol action on macrophage adhesion, which should be further investigated as an inflammatory control.
ABSTRACT
This study evaluated, in vitro, the antimicrobial activity and the anti-adherent property of xylitol (0.5, 2.5 and 5.0 percent, w/v) on two Pseudomonas aeruginosa strains (ATCC 9027 and clinical). The assay of antimicrobial activity was performed to determine a minimum inhibitory concentration (MIC) and the adhesion test was performed, by which the parameters regarding, growth in the culture medium, number of colony forming units (CFUs) released and slide evaluation by scanning electron microscopy (SEM) were analyzed. The Statistical Package for the Social Sciences (SPSS) was employed for statistical analysis. Results showed that xylitol had no antimicrobial activity on these strains; however, the inhibition of bacterial adherence was observed in microphotographs obtained by SEM. These results indicated that xylitol could be a future alternative to combat bacterial colonization.
ABSTRACT
The present study aimed to evaluate xylitol's antimicrobial and anti-adherence activities on Escherichia coli (ATCC 8739) and on another clinical strain enteropathogenic E. coli (EPEC). In vitro minimum inhibitory concentration (MIC) test and adhesion assays were performed using 0.5, 2.5 and 5.0 percent xylitol. It was found that xylitol did not have antimicrobial properties on these strains. The scanning electron microscopy (SEM) demonstrated that the slides treated with xylitol had a significant reduction in the number of bacilli and the inhibition of microbial adhesion was probably the xylitol's mechanism of action. Xylitol could be a possible alternative on the control of E. coli infections.
ABSTRACT
The effect of glucose on xylose-to-xylitol bioconversion by Candida guilliermondii was examined by adding it to sugarcane bagasse hydrolysate medium to obtain different glucose:xylose ratios (1:25, 1:12, 1:5 and 1:2.5). Under experimental conditions, increasing glucose:xylose ratio improved the assimilation of the xylose present in the hydrolysate by yeast, resulting in biomass increase, and in the formation of xylitol and glycerol/ethanol by-products. Maximum values of xylitol yield (0.59 g g-1) and volumetric productivity (0.53 g l-1.h-1) were obtained with glucose:xylose ratio of 1:5, resulting in the higher conversion efficiency (64.3 percent).
O efeito da glicose na bioconversão de xilose em xilitol por Candida guilliermondii foi avaliado em hidrolisado hemicelulósico de bagaço de cana com diferentes relações glicose:xilose (1:25, 1:12, 1:5 and 1:2,5). Sob as condições experimentais, o aumento da relação glicose:xilose favoreceu a assimilação da xilose presente no hidrolisado, resultando em aumento da biomassa celular e aumento da formação de xilitol e dos sub-produtos glicerol e etanol. Os valores máximos do fator de conversão de xilose em xilitol (0,59 g g-1) e da produtividade volumétrica de xilitol (0,53 g l-1.h-1) foram obtidos com a relação glicose:xilose 1:5, resultando na maior eficiência de conversão (64,3 por cento).
ABSTRACT
Xylose-to-xylitol bioconversion by Ca-alginate entrapped Candida guilliermondii cells in sugarcane bagasse hemicellulosic hydrolysate was carried out in erlenmeyer flasks using the repeated-batch mode of fermentation. The hydrolysate was supplemented or not with ammonium sulfate and/or rice bran extract at the beginning of each repeated batch. Altogether, six sets of three repeated-batches were carried out, the immobilized cells being reused at the end of each batch. The best results were achieved when the hydrolysate was supplemented with both nutrients in all the three repeated batches, which provided xylitol productions of 25.9, 46.8, 48.7 gL-1, productivities of 0.27, 0.49, 0.51 gL-1h-1, and yields of 0.45, 0.58, 0.55 gg-1, respectively. In the absence of nutrients, the xylitol production, productivity and yield did not exceed 12.1 gL-1, 0.13 gL-1h-1 and 0.30 gg-1, respectively.
A bioconversão de xilose em xilitol por células de Candida guilliermondii imobilizadas em alginato de cálcio, em hidrolisado hemicelulósico de bagaço de cana-de-açúcar, foi realizada em frascos erlenmeyer no modo bateladas repetidas de fermentação. O hidrolisado foi suplementado ou não com sulfato de amônio e/ou extrato de farelo de arroz no início de cada batelada repetida. No total, seis experimentos com três bateladas repetidas cada um foram realizados, sendo as células imobilizadas reutilizadas ao final de cada batelada. Os melhores resultados foram alcançados quando o hidrolisado foi suplementado com ambos nutrientes em todas as três bateladas repetidas, resultando em concentrações de xilitol iguais a 25,9, 46,8 e 48,7 gL-1, produtividades de 0,27, 0,49 e 0,51 gL-1h-1, e rendimentos de 0,45, 0,58 e 0,55 gg-1, respectivamente. Na ausência de nutrientes, a concentração de xilitol, a produtividade e o rendimento não ultrapassaram 12,1 gL-1, 0,13 gL-1h-1 e 0.30 gg-1, respectivamente.
Subject(s)
Fermentation , Saccharum , Xylitol , Biodegradation, Environmental , Biotechnology , Industrial MicrobiologyABSTRACT
A producao de xilitol por Candida guilliermondii FTI 20037 foi avaliada em meio semi-sintetico contendo xilose como principal fonte de carbono , tendo sido usados biorreatores de mistura (agitacao = 300 rpm; regimes: descontinuo e continuo) e de leito fluidizado (operado com celulas imobilizadas em esferas de vidro poroso). As condicoes que permitiram obter a maior produtividade em xilitol (0,32g/L.h) em biorreator de mistura descontinuo foram: pH:2,5 a 4,0; Temperatura: 30 graus centigrados; Aeracao = 20mL ar/min (kLa =1,5 'h POT. -1'); Idade do inoculo = 40h e Concentracao inicial de xilose = 100g/L. A producao de xilitol foi otimizada (produtividade = 1,35g/L.h) atraves do uso do biorreator de leito fluidizado contendo celulas de levedura imobilizadas e mantido nas condicoes acima. Verificou-se que a presenca de acido acetico, furfural, metanol e glicose no mosto inibiam a producao de xilitol