Utilization of agroindustrial byproducts for the production of lipase by a new strain of Pseudomonas sp.

Este estudo teve como objetivo avaliar a produção de lipases por uma nova cepa de Pseudomonas sp. utilizando meio de fermentação contendo subprodutos de industrialização de carne de frango e óleo de soja. Os resultados indicaram que a gordura de frango e a goma de soja induziram 48,3 U/mL e 93,3 U/ml de atividade lipásica, respectivamente. No entanto, a produção de lipase mais elevada foi obtida quando a goma de lecitina bruta foi utilizada, induzindo 272,6 U/ml de atividade após 24 horas. A caracterização bioquímica parcial da enzima mostrou que as condições de reação ótimas foram de pH 9,0 e 35°C. A enzima foi estável nas temperaturas entre 25 a 75°C e pH de 6 a 9. A enzima mostrou boa estabilidade em solventes orgânicos tais como acetonitrila, hexano, etanol e isopropanol. Este estudo indicou que os subprodutos testados são promissores para a produção de lipase e podem contribuir para a redução dos custos de produção enzimática em larga escala, aumentar o valor desses subprodutos e reduzir potenciais impactos ambientais causados por sua acumulação na natureza.

PSXIV-26 Effect of effective microorganisms (EM®) and milk whey or molasses on in vitro digestibility of corn stover silage

Corn stover (CS) is an agricultural by-product widely used in the ruminant feeding systems, despite its poor nutritional value and digestibility. Although treatments such as alkalinization, pelleting and extruded have been evaluated to improve its digestibility, the use of those treatments is limited. An alternative might be the use of EM (cocktail of mainly lactic bacteria), although there is no information about the optimal dose to improve DM digestibility of CS. On the other hand, there are agroindustrial byproducts such as milk whey and molasses that can be used as energy sources for ensiling. The objective of this study was to evaluate the level of EM® and the type of energy substrate on in vitrodry matter digestibility (IVDMD) and pH of CS silage. Microsilos were elaborated in plastic bottles, which were assigned to a completely randomized design with factorial arrangement 4 (levels: 0, 0.5, 1.0 and 1.5 ml/kg as feed of EM®) × 2 (energy source:milk whey or molasses, 15%), with five repetitions each. Results were analyzed using the GLM procedure of SAS. Orthogonal polynomials were tested to determine linear and quadratic effects of EM® dosis. Interaction of dose × energy source was observed (P < 0.05). The highest IVDMD and lowest pH was observed with addition of 0.5 mL and 1 mL of EM® and milk whey. IVDMD linearly increased and pH was reduced (P < 0.05) with the increasing levels of EM®). It is concluded that addition of EM® at doses of 0.5 to 1 mL / kg DM improved IVDMD and that milk whey is the best source of energy for the ensiling of CS.

Production of L-asparaginase by Aspergillus niveus under solid-state fermentation using agroindustrial byproducts

<p class="abstract"><strong>Background:</strong> L-asparaginase, produced mainly by microrganisms, cleaves L-asparagine to aspartic acid and ammonia as products. This enzyme has been applied in the treatment of the leukemia and in food preparation preventing the acrylamide formation.</p><p class="abstract"><strong>Methods:</strong> <em>Aspergillus niveus</em> was grown in different solid substrates (agroindustrial byproducts) moistened with different agents (tap water, distilled water and several salt solutions) for different periods (24-240 h) at 30ºC. The enzyme extract was obtained with the addition of cold distilled water, agitation at 50 rpm for 30 min and filtration. The filtrate was used to determine the L-asparaginase activity through the hydroximate aspartic methodology using L-asparagine as substrate. The influence of temperature (30-75ºC), pH (3-9) and chemical compounds on the enzyme activity was analyzed. </p><p class="abstract"><strong>Results:</strong> The highest level of enzyme production was obtained using the M1 mixture (wheat bran, crushed soybean, orange peel; 1:1:1, w/w/w) as substrate humidified with Czapeck Dox salt solution (1:0.5, m/v) for 48-120 h, at 30ºC. The best temperature and pH for the enzyme activity were 35ºC and 5.0, respectively. The enzyme activity was increased in the presence of NaCl and some organic solvents (acetonitrile, butanol ethanol, isopropanol and methanol).</p><p class="abstract"><strong>Conclusions:</strong> <em>A. niveus</em> produced L-asparaginase under SSF using a mixture of agroindustrial byproducts as solid substrate in the absence of L-asparagine as inducer. The temperature and pH of activity, as well as the NaCl tolerance, indicate its potential to be applied for different purposes. <em>A. niveus</em> can be an interesting source of L-asparaginase gene to be investigated targeting future application.</p><p class="abstract"> </p>