Abstract Biotechnological production of carotenoids can be affected by cultivation conditions, such as temperature, pH and agitation. The aim of this study was to maximize carotenoid production by Sporidiobolus pararoseus in shake flasks with agroindustrial by-products as substrates. The best conditions were used in a stirred tank fermenter. The medium consisted of corn steep liquor and sugar cane molasses pretreated with sulfuric acid. In order to evaluate the effects of the variables, a central composite rotatable design was used. The highest values of total carotenoids (565 µg L-1), biomass (13.6 g L-1) and Yp/s (10.9 µg g-1) were obtained in Assay 13 at 27.5ºC, 150 rpm and pH=4, in Erlenmeyer flasks. For the best conditions defined for carotenoid productivity and 1.2 vvm in the stirred tank fermenter, the maximum value was 1969.3 µg L-1 of total carotenoids. It was 3.5-fold higher than the value obtained when shake flasks were used.

O interesse pela produção de carotenoides por fontes naturais é crescente, em decorrência da possibilidade de atuar como corante e sua capacidade antioxidante biológica potente. Neste estudo, avaliou-se o uso da água de parboilização do arroz, como substrato alternativo para a bioprodução de carotenoides, usando a levedura Phaffia rhodozyma que, como única fonte de nutrientes, foi promissora, alcançando 0,6 μg mL-1 (259,1 μg g-1) em 48 h. Para aumentar o potencial de aproveitamento desse efluente industrial, um estudo da suplementação do meio de produção foi realizado para incrementar a obtenção dos carotenoides, utilizando a metodologia do planejamento fatorial (um planejamento fatorial 2IV 6-2 sequenciado por um planejamento fatorial completo 24). As condições maximizadas de produção de carotenoides foram (g L-1): extrato de malte, 16,25; peptona, 15 e água de parboilização de arroz, 87,5, com pH 5, a 25 ºC, 150 rpm por 144 h, alcançando 5,3 μg mL-1 (628,8 μg g-1).

The interest in carotenoid production from natural sources has increased based in their possible use as dyes and their powerful biological antioxidant capacity. This study evaluated the use of rice parboiling wastewater (RPW) as an alternative substrate for the bioproduction of carotenoids using the yeast Phaffia rhodozyma and found it to be promising as the only source of nutrients, reaching a concentration of 0.6 μg mL-1 (259.1 μg g-1) in 48 h. To increase the potential use of this industrial effluent, a study of supplementation was carried out to enhance the production of carotenoids using the methodology of experimental design (a 2IV 6-2 fractional factorial design sequenced by a 24 central composite design). The conditions for maximizing the production of carotenoids were (g L-1) malt extract (16.25), peptone (8.75), sucrose (15) and rice parboiling wastewater (87.5), with a pH of 5 at 25 °C and 150 rpm for 144 h, which produced a concentration 5.3 μg mL-1 (628.8 μg g-1).

A procura por alimentos funcionais, como leites fermentados com culturas microbianas probióticas, aumentou o interesse em pesquisas para manter estes micro-organismos viáveis no produto. Neste sentido, o objetivo deste trabalho foi formular um leite fermentado sabor morango agregado de benefícios potencialmente prebióticos e probióticos, apresentando características sensoriais adequadas. Um planejamento fatorial 2³ com ponto central foi realizado para otimizar a saborização do produto, avaliando a adição de sacarose (50, 85 e 120 g.L-1), corante natural carmim cochonilha (0,5; 1,0 e 1,5 g.L-1) e aroma natural de morango (0,10; 0,25 e 0,40 g.L-1). Diferentes concentrações da cultura Bio Rich (L. acidophilus, Bifidobacterium e S. thermophilus) foram testadas (1,00; 0,50 e 0,33 g.L-1), ordenando-se sensorialmente conforme a preferência. Concentrações do xarope de fruto-oligossacarídeos (50 e 100 g.L-1) foram avaliadas por meio de aceitação sensorial e análises microbiológicas. Um leite fermentado sabor morango utilizando, em g.L-1, 0,33 de cultura, 120 de sacarose, 1,5 de corante, 0,4 de aroma e 100 de xarope de fruto-oligossacarídeos, foi desenvolvido. O incremento da concentração de prebiótico influenciou positivamente na preferência do produto, apresentando índice de aceitação de 88%; microbiologicamente, aumentou a contagem de L. acidophilus e Bifidobacterium, sendo 1,7 × 10(7) e 4,8 × 10(6) UFC.mL-1, respectivamente, com 100 g.L-1 de prebiótico.

The demand for functional foods, including milk fermented with probiotic microbial cultures, has increased the interest in research to maintain these microorganisms viable in the product. Thus the objective of this work was to formulate strawberry flavoured fermented milk with added potentially beneficial prebiotics and probiotics, and with suitable sensory characteristics. A 2³ experimental design was used to optimize the product flavour, evaluating the addition of sucrose (50, 85 and 120 g.L-1), the natural dye cochineal carmine (0.5, 1.0 and 1.5 g.L-1) and a natural strawberry aroma (0.10, 0.25 and 0.40 g.L-1). Different concentrations of Bio Rich culture (L. acidophilus, Bifidobacterium and S. thermophilus) were tested (1.00, 0.50 and 0.33 g.L-1) ranking the products in according to sensory preference. Two fructo-oligosaccharide syrup concentrations (50 and 100 g.L-1) were evaluated according to their sensory acceptability and microbiological analyses. A strawberry flavoured fermented dairy beverage was developed using (g.L-1) 0.33 culture, 120 sucrose, 1.5 dye, 0.4 aroma and 100 fructo-oligosaccharide syrup. The increase in concentration of the prebiotics positively influenced product preference, with acceptance rates of 88% and increased microbiological counts of L. acidophilus and Bifidobacterium at 1.7 × 10(7) and 4.8 × 10(6) CFU.mL-1 for 100 g.L-1 of prebiotics.

No processo em um único estágio com a adição simultânea de β-galactosidase e de cultura lática, foram avaliadas a conversão da lactose, o tempo de processamento, a viscosidade e a sinérese. A fermentação foi promovida por cultura láctica, contendo dois micro-organismos probióticos, Bifidobacterium animalis e Lactobacillus acidophilus, associados aos micro-organismos característicos do iogurte. Foi utilizado um preparado enzimático contendoβ-galactosidases obtidas de Kluyveromyces lactis e de Aspergillus niger. Os efeitos da concentração inicial de lactose, concentração de enzima e tempo de adição da enzima foram avaliados por meio de um planejamento experimental (2³ ensaios mais três pontos centrais). As seguintes condições foram estabelecidas: concentração inicial de lactose de 91 g L-1, concentração de enzima de 0.5 g L-1 e adição da enzima no início da fermentação. Nessas condições, um decréscimo no tempo de processamento (de 4,55 h para 3,68 h) e um incremento na conversão de lactose (de 15,2% para 97,9%) foram observados em relação à fermentação sem a adição da enzima, sem alterações prejudiciais em algumas propriedades físicas do iogurte (viscosidade, e sinérese).

In a single-stage process with the simultaneous addition of β-galactosidase and lactic culture, the lactose conversion, the processing time, viscosity and syneresis were evaluated. Fermentation was promoted by lactic culture containing two probiotic microorganisms, Bifidobacterium animalis and Lactobacillus acidophilus, associated with the typical microorganisms of yogurt. An enzymatic preparation containing β-galactosidases from Kluyveromyces lactis and Aspergillus niger was used. A central composite design (2³ trials plus three central points) was proposed in order to evaluate the effects of initial lactose concentration, enzyme concentration and the time of addition of the enzyme. The following conditions were established: initial lactose concentration of 91 g L-1, enzyme concentration of 0.5 g L-1 and enzyme addition at the beginning of fermentation. In these conditions, a decrease in processing time (from 4.55 to 3.68 h) and an increase in lactose conversion (from 15.2 to 97.9%) were observed in relation to the fermentation without enzyme addition, and no detrimental changes in some physical properties of yogurt (viscosity, and syneresis).

The work herewith investigated the production of yeast biomass as a source of protein, using Yarrowia lipolytica NRRL YB-423 and raw glycerol from biodiesel synthesis as the main carbon source. A significant influence of glycerol concentration, initial pH and yeast extract concentration on biomass and protein content was observed according to the 2v5-1 fractional design. These factors were further evaluated using a central composite design and response surface methodology, and an empirical model for protein content was established and validated. The biomass of Yarrowia lipolytica NRRL YB-423 reached 19.5 ± 1.0 g/L in shaken flasks cultivation, with a protein content of 20.1 ± 0.6% (w/w).

O objetivo deste trabalho foi estudar a influência de parâmetros reacionais na obtenção via enzimática de galacto-oligossacarídeos (GOS), utilizando-se a enzima comercial β-galactosidase de Kluyveromyces lactis (Lactozym® 3000 L), tendo como substrato a lactose. Foi proposto um planejamento experimental 2³, verificando a influência da temperatura (30 a 40 °C), da concentração de lactose (200 a 400 mg.mL-1) e da concentração de enzima (5 a 10 U.mL-1) no desempenho da reação enzimática. Os ensaios foram conduzidos a 180 rpm e pH 7,0 (tampão fosfato de sódio 0,1 M). A enzima Lactozym® 3000 L apresentou atividade de transgalactosilação, tendo sido atingido rendimento do processo igual a 41,9% e concentração de GOS de 167,5 mg.mL-1 no sistema reacional composto por 400 mg.mL-1 de lactose e 5 U.mL-1 de enzima a 30 °C em 14 h de reação. Nessa condição, a conversão de lactose foi de 65,0%. Maior concentração de lactose foi favorável ao mecanismo de transgalactosilação, enquanto que, em menores concentrações, o mecanismo hidrolítico predominou.

The main goal of this work was to study the influence of the reaction parameters on the enzymatic production of galactooligosaccharides (GOS) using the commercial β-galactosidase from Kluyveromyces lactis (Lactozym® 3000 L) and lactose as the substrate. A 2³ experimental design was proposed, verifying the influence of the temperature (30 to 40 °C), lactose concentration (200 to 400 mg.mL-1) and enzyme concentration (5 to 10 U.mL-1) on the performance of the enzymatic reaction. The assays were carried out at 180 rpm and pH 7.0 (0.1 M sodium phosphate buffer). The enzyme Lactozym® 3000 L presented transgalactosylation activity, reaching a yield of 41.9% and GOS concentration of 167.5 mg.mL-1 in a reaction system composed of 400 mg.mL-1 of lactose and 5 U.mL-1 of enzyme at 30 °C and 14 h of reaction. Under these conditions the lactose conversion was 65.0%. Higher lactose concentrations favored the transgalactosylation mechanism, whereas the hydrolytic mechanism dominated with lower concentrations.

Isoamyl butyrate production was investigated using free and immobilized lipases by esterification of butyric acid with isoamyl alcohol in a solvent-free system and in an organic media. Among the enzymes studied, Lipozyme TL IM was found to be the most active catalyst in n-hexane as a solvent. The effects of different solvents and the amount of water added on conversion rates were studied. A maximum conversion yield of 80% in n-hexano at 48 h was obtained under the following conditions: 3 g L-1 of Lipozyme TL IM, 30 ºC, 180 rpm of agitation, isoamyl alcohol to butyric acid molar ratio of 1:1 and acid substrate concentration of 0.06 M.

The main goal of this work was to study the biodegradation of phenol in batch mode by a filamentous fungus isolated from a contaminated site in Southern Brazil. A better performance was obtained by previous adaptation of the microorganism to the toxic chemical. A 2³ experimental design was proposed and it could be observed total phenol degradation in 72 h using 500 mg L-1 glucose, inoculum of 20% and agitation of 200 rpm, resulting a biodegradation rate of 3.76 mg L-1 h-1. In relation to phenol tolerance, Aspergillus sp. LEBM2 was able to consume up to 989 ± 15 mg L-1.

The objective of this paper was to determine nitrate and nitrite anions in toasted fish skin tea, which the population of southern Rio Grande do Sul believes to have pharmacological properties for trating asthma. Two methods were compared, an official and one described by Guozhen et al., that has the advantage of not needing reduction of nitrate to nitrite on a Cd column. The samples were the skin of the fish species Balistes capriscus (peixe porco) and Menticirrhus littoralis (papa-terra), both crude and toasted, as traditionally used. The method of Guozhen et al. was used due to its performance (detection limit 0.005 µmol/L NO3- and 0.02 µmol/L - NO2- and mean recuperation of 100 and 97% respectively for each anion) and results similar to those of the official methods under conditions used by the population, the estimated daily intake, of the teas is equivalent to 0.03 to 0.05 mg of nitrate and 0.007 to 0.014 mg of nitrite. These values are in accord with safety recommendations and don't represent a health risk.