Resumo O presente trabalho teve como objetivo estudar a melhor composição do meio de fermentação para máxima produção de lactase por Saccharomyces fragilis IZ 275 usando diferentes fontes de carbono incluindo o soro de queijo em pó reconstituído. Primeiramente, um delineamento fatorial 24 foi aplicado para verificar dentre as variáveis estudadas as que apresentavam efeito significativo. Logo após, foi aplicado um delineamento de máxima inclinação ascendente e máxima inclinação descendente para obter a máxima atividade. Para otimizar o meio de fermentação, foi então, realizado um delineamento Composto Central Rotacional (DCCR) 24. Foi observado que o soro de queijo, um subproduto da indústria de lacticínios, e altamente poluidor para o meio ambiente, pode ser empregado como excelente meio de fermentação por leveduras, dentro do conceito de bioeconomia com valor agregado. O emprego da metodologia é uma ferramenta eficiente para otimizar o processo de produção da β-galactosidase. No meio de fermentação otimizado, a máxima produção de β-galactosidase (54,68 U/mL) por S. fragilis IZ 275 é obtida com 14 g/L sacarose, 17,7 g/L soro de queijo em pó reconstituído, 5,14 g/L extrato de levedura e 8,85 g/L peptona.

Abstract This study sought to create a better fermentation medium to maximize lactase production by Saccharomyces fragilis IZ 275 using different carbon sources, including reconstituted powdered cheese whey. A factorial design 24 was applied to evaluate the significant effects of variables which compose the fermentation medium. Then, a steepest descent-ascent design was applied to obtain the maximum activity. A Rotational Central Composite Design (RCCD) 24 was made to optimize the fermentation medium. We verified that the cheese whey, a by-product of the dairy industry, can be employed as an excellent fermentation medium by yeast, within the bioeconomy concept and used by the dairy industry as product with additional value. The employed methodology is an efficient tool in the optimization process for β-galactosidase production. In the optimized fermentation medium, the maximum production of β-galactosidase (54.68 U/mL) by S. fragilis IZ 275 is obtained with 14 g/L sucrose, 17.7 g/L reconstituted powdered cheese whey, 5.14 g/L yeast extract and 8.85 g/L peptone.

Abstract The cheese whey shows an organic nutrient charge that can be used to obtain metabolites of interest by biotechnology of microorganisms. Thus, fermentative processes for enzyme production, in particular beta-galactosidase becomes feasible. The enzyme plays an important role in the biotech food industry to obtain milk and dairy products with low lactose content for consumption by intolerant individuals. The objective of this work was to determine the enzyme activity of the concentrated beta-galactosidase (CBG) and the permeabilized cells (PC) both obtained from Saccharomyces fragilis IZ 275. The enzyme beta-galactosidase obtained from the fermentation of Saccharomyces fragilis IZ 275 in cheese whey was used to determine the optimal conditions for the hydrolysis of lactose solution at 1% (w/v). Response Surface Methodology (RSM) by Box-Behnken Design (BBD) was employed to determine beta-galactosidase activity for such factors pH, temperature and enzyme concentration suitable for the lactose hydrolysis. Based on the statistical analysis, the optimum operational conditions for maximizing lactose hydrolysis thus optimizing the enzyme activity for CBG were, temperature 30 °C, pH 6.0 and enzyme concentration 3% (v/v) and for PC was temperature 44 °C, pH 7.0 and enzyme concentration 4% (v/v).

Resumo: Este artigo analisa o letramento digital de alunos ingressantes no ensino superior, destacando os aspectos do conhecimento computacional, comunicacional e informacional. Realizou-se uma pesquisa descritiva exploratória quantitativa analítica e, como técnica específica para obter as informações requeridas, utilizou-se um questionário composto por 12 questões sobre aspectos relacionados à competência computacional, comunicacional e informacional, adaptadas dos estudos de Ribeiro e Behar (2013), além de campos referentes ao perfil dos respondentes. Nesta pesquisa, que obteve 410 respostas, foi possível verificar a associação entre idade e conhecimento computacional, conhecimento comunicacional e conhecimento informacional. Os discentes mais jovens possuíam maior conhecimento nas dimensões pesquisadas, segundo o Teste de Mann-Whitney (p<0,05). Não houve diferenças entre as Regiões Centro-Oeste e Nordeste, locais das pesquisas. Evidenciou-se que o conhecimento de programas de computador não implicava domínio das ferramentas computacionais inerentes a eles. Não houve correlação entre conhecer programas computacionais e possuir habilidades computacionais. Ademais, 8% de ingressantes do ensino superior não possuíam conhecimento acerca de qualquer programa computacional, e 18% dos respondentes declararam ter dificuldades para localizar informações.

Abstract: This paper analyzes digital literacy in students entering higher education, highlighting aspects of the computational, communicative and informational knowledge. It was conducted an analytical quantitative descriptive exploratory research and, as a specific technique to collect data, a questionnaire with 12 questions was designed about aspects related to the computational, communicative and informational skill, adapted from studies by Ribeiro and Behar (2013), with fields about the profile of the participants. This study, in which 410 answers were gathered, found that there is a relation between age and the computational, communicative and informational knowledge. Younger students were more knowledgeable in the surveyed areas, according to Mann-Whitney test (p <0.05). When it comes to the places in which the research took place, was found no difference between the midwest and the northeast regions. Moreover, a knowledge of computer programs does not imply mastery of their computational tools. No correlation was found between knowing computer programs and having computational skills. Thus, eight percent of freshmen in higher education had no knowledge of computer programs and eighteen percent of the participants reported difficulties to find digital information.

Resumo O soro de queijo é o líquido resultante da coagulação do leite durante a manufatura do queijo. Em adição, o soro de queijo é uma importante fonte de poluição ambiental. O principal objetivo do presente experimento foi comparar a produção de β-galactosidase (EC 3.2.1.23) por Aspergillus oryzae a partir de uma solução de soro de queijo desproteinizada e não-desproteinizada por fermentação submersa. Para se determinar a atividade enzimática, um meio reacional contendo extrato livre de células e orto-nitrofenol-β-galactosídeo (ONPG) foi usado. Os resultados indicaram que a indução de β-galactosidase foi maior quando usada solução de SQP desproteinizada comparada à solução não-desproteinizada. Estes resultados podem permitir uma gestão alternativa do soro de queijo, diminuindo assim seu impacto no ambiente e produzindo biomacromoléculas de valor agregado.

Abstract Whey is the liquid that results from the coagulation of milk during cheese manufacture. Cheese whey is also an important environmental pollution source. The present experiment sought to compare β-galactosidase (EC 3.2.1.23) production by Aspergillus oryzae from deproteinized and un-deproteinized CWP solutions. β-galactosidase was produced by submerged fermentation in deproteinized or un-deproteinized CWP solutions. To determine the activity of the enzyme, a reaction mixture containing cell-free extract and ortho-Nitrophenyl-β-galactoside (ONPG) was used. The results indicated that β-galactosidase induction was greater when using deproteinized CWP solution compared to the un-deproteinized CWP solution. These results may enable an alternative management of cheese whey, thereby decreasing its impact on the environment and producing value-added biomacromolecules.

Abstract The commercial enzyme (E.C. = 3.2.1.23) from Kluyveromyces lactis (liquid) and Aspergillus oryzae(lyophilized) was investigated for its hydrolysis potential in lactose substrate, UHT milk, and skimmed milk at different concentrations (0.7; 1.0 and 1.5%), pH values (5.0; 6.0; 6.5 and 7.0), and temperature (30; 35; 40 and 55 ºC). High hydrolysis rates were observed for the enzyme from K. lactis at pH 7.0 and 40 ºC, and from A. oryzae at pH 5.0 and 55 ºC. The enzyme from K. lactis showed significantly higher hydrolysis rates when compared to A. oryzae. The effect of temperature and β-galactosidase concentration on the lactose hydrolysis in UHT milk was higher than in skimmed milk, for all temperatures tested. With respect to the thermal stability, a decrease in hydrolysis rate was observed at pH 6.0 at 35 ºC for K. lactisenzyme, and at pH 6.0 at 55 ºC for the enzyme from A. oryzae. This study investigate the hydrolysis of β-galactosidase in UHT and skimmed milk. The knowledge about the characteristics of the β-galactosidase fromK. lactis and A. oryzae enables to use it most efficiently to control the enzyme concentration, temperature, and pH in many industrial processes and product formulations.

The production of value-added products could be a valuable option for cheese wastewater management. However, this kind of study cannot just focus alone on getting the final product. This also necessitates studies on the dynamics of bioprocesses. With these as background, the present investigation aimed at evaluating the buffering capacity of deproteinized whey and effect of temperature and nitrogen source on ethanol yields from it. The batch fermentation conditions used to evaluate ethanol production were temperatures 30, 35, 40°C and pH 4.5, 5.0, 5.5, 6.0. To study the influence of nitrogen source on ethanol yield, a design matrix was applied using yeast extract and (NH4)2SO4.The final pH was analyzed to evaluate the buffering capacity. The results showed that the Kluyveromyces marxianus was thermotolerance to produce ethanol at 35 and 40°C, which was not observed at 30°C. Results also showed that the deproteinization procedure did not affect the buffering capacity of cheese whey. Finally, higher ethanol production was obtained using yeast extract (3% v/v). These results could be important for developing low-cost method for industrial production of ethanol from deproteinized whey.

The use of residues from dairy industry is interesting because of the ease of acquisition and a relatively low cost. The objective of this study was to analyze ethanol production by the Saccharomyces fragilis varying the concentration of cheese whey powder (CWP) solution, initial pH and inoculum concentration using a factorial design technique; besides, semi-batch operations to add lactose was investigated. Statistical analysis was performed by ANOVA (p≤0.05). The concentrations of CWP solution and initial pH were significant in the fermentation medium for ethanol production. The optimum conditions were CWP solution 15 %, pH 5.0, inoculum concentration 5 % and a fermentation time of 18 h, and ethanol production reached 7.6 % (v/v). Additionaly, semi-batch operations performed to add lactose also modified the ethanol yield (10.67 % v/v). This would be the first time that a high ethanol production rate was obtained from S. fragilis using cheese whey powder solution and a factorial design technique.

El uso de residuos de la industria lechera es interesante por la facilidad de adquisición y costo relativamente bajo. El objetivo de este estudio fue analizar la producción de etanol por Saccharomyces fragilis variando la concentración de solución de suero en polvo de queso (CWP), pH inicial y concentración del inóculo, con una técnica de diseño factorial; además, se investigaron operaciones de semi lotes para agregar la lactosa. El análisis estadístico realizado fue ANOVA (p≤0.05). Las concentraciones de la solución CWP y el pH inicial fueron significativas en la fermentación del medio para la producción de etanol. Las condiciones óptimas fueron 15 % de solución CWP, pH 5.0, concentración de inóculo de 5 % y tiempo de fermentación de 18 h, y la producción de etanol alcanzó 7.6 % (v/v). Además, por operaciones de semi lotes realizadas para agregar lactosa también se modificó la producción de etanol (10.67 % v/v). Esta sería la primera vez que se obtiene una tasa alta de producción de etanol de S. fragilis usando solución de polvo de suero de queso y una técnica de diseño factorial.