The influence of use additives on nitrous oxide emission during swine slurry composting.

use of additives (Mg/P and nitrification inhibitor dicyandiamide - DCD), on nitrous oxide emission during swine slurry composting. The experiment was run in duplicate; the gas was monitored for 30 days in different treatments (control, DCD, Mg/P and DCD + Mg/P). Nitrous oxide emissions rate (mg of N2O-N.day-1) and the accumulated emissions were calculated to compare the treatments. Results has shown that emissions of N-N2O were reduced by approximately 70, 46 and 96% through the additions of DCD, MgCl2.6H2O + H3PO4 and both additives, respectively, compared to the control. Keywords Composting; swine slurry; additives; nitrou

Purification and characterization of xylanases from the fungus Chrysoporthe cubensis for production of xylooligosaccharides and fermentable sugars

Xylanases from the pathogen fungus Chrysoporthe cubensis were produced under solid state fermentation (SSF) using wheat bran as carbon source. The enzymatic extracts were submitted to ion exchange (Q Sepharose) and gel filtration chromatography methods (Sephadex S-200) for purification. The xylanases were divided into three groups: P1 showed better performance at 60 °C and pH 4.0, P2 at 55 °C and pH 3.0, and P3 at 80 °C and pH 3.0. Oat spelt xylan was the best substrate hydrolyzed by P1 and P3, while beechwood xylan was better degraded by P2. Carboxymethyl cellulose (CMC) and p-nitrophenyl-β-d-xylopyranoside (p-NPβXyl) were not hydrolyzed by any of the xylanases. The K M ’ or K M values, using oat spelt xylan as substrate, were 2.65 mg/mL for P1, 1.81 mg/mL for P2, and 1.18 mg/mL for P3. Xylobiose and xylotriose were the main xylooligosaccharides of oat spelt xylan degradation, indicating that the xylanases act as endo-β-1,4-xylanases. Xylanases also proved to be efficient for hydrolysis of sugarcane bagasse when used as supplement of a commercial cocktail due to the increase of the reducing sugar release

Hydrolysis of galacto-oligosaccharides in soy molasses by α -galactosidases and invertase from Aspergillus terreus

Two &#945; -galactosidase (P1 and P2) and one invertase present in the culture of Aspergillus terreus grown on wheat straw for 168 h at 28ºC were partially purified by gel filtration and hydrophobic interaction chromatographies. Optimum pH and temperatures for P1, P2 and invertase preparations were 4.5-5.0, 5.5 and 4.0 and 60, 55 and 65ºC, respectively. The K M app for Ï� -nitrophenyl-&#945; -D-galactopyranoside were 1.32 mM and 0.72 mM for P1 and P2, respectively, while the K M app value for invertase, using sacarose as a substrate was 15.66 mM. Enzyme preparations P1 and P2 maintained their activities after pre-incubation for 3 h at 50ºC and invertase maintained about 90% after 6 h at 55 ºC. P1 and P2 presented different inhibition sensitivities by Ag+, D-galactose, and SDS. All enzyme preparations hydrolyzed galacto-ologosaccharides present in soymolasses.<br>Duas &#945;-galactosidases (P1 e P2) e uma invertase produzidas no sobrenadante da cultura do fungo Aspergillus terreus quando crescido por 168 h a 28ºC com farelo de trigo como fonte de carbono foram parcialmente purificadas por cromatografias de gel filtração e interação hidrofóbica. O pH e temperatura ótimos para as preparações P1, P2 e invertase foram entre 4,5-5,0, 5,5 e 4,0 e 60, 55 e 65ºC, respectivamente. O K M app para Ï�-nitrofenil-&#945;-D-galactopiranosideo foi 1.32 mM e 0.72 mM para P1 e P2, respectivamente. O valor de K M app para invertase usando sacarose como substrato foi de 15,66 mM. As preparações enzimáticas P1 e P2 mantiveram suas atividades após 3 h de pré-incubação a 50 ºC e a invertase manteve cerca de 90% após 6 h a 55 ºC. P1 e P2 foram diferentemente sensíveis à inibição por Ag+, D-galactose e SDS. As preparações enzimáticas hidrolisaram os galactooligossacarídeos presentes em melaço de soja