Production of Lipase Using Cassava Peel and Sunflower Oil in Solid-State Fermentation： Preliminary Study

Full use of residues from industrial processes is a fundamental necessity of contemporary society, since it avoids impacts to the environment by using residues as inputs for other products of high economic and social importance. In this study, lipase production of the crude enzymatic extracts obtained by Aspergillus niger using cassava peel as substrate and sunflower oil as an inductor was investigated. The optimized cultivation temperature and concentration of inductor were determined using the response surface methodology. The two variables studied exercised influence in the production of lipase in the 95% level of confidence. The response surface obtained indicated that the conditions that maximize lipase activity production were 30.5 ~C and initial concentration of sunflower oil was 2.5% （w/w）. Through this analysis, it is evident that extremes in temperature and concentration of inductor tend to decrease lipase production, since low temperatures decrease metabolism and high temperatures may inactivate the lipase. Optimum lipase yield was 59.8 U/g of dry peel which was fermented for 60 h. Lipase production presents a peak of 61.3 U/g, at 72 h of fermentation. However, this value is statistically equal （p 〉 0.05） of the value of lipase activity obtained for 60 h and 84 h of fermentation.     

Increased CO2 emission and organic matter decomposition by leaf-cutting ant nests in a coastal environment

Leaf-cutting ants perform a vital role in the cycling of carbon and nutrients in tropical ecosystems. Nests have high levels of organic matter and refuse dumps host up to two times more soil micro-organisms than non-nest soil. The increased levels of organic matter in the soil of nests, however, can affect CO₂ emissions from soil and alter the balance of atmospheric CO₂. We aimed at assessing the effect of nests of the leaf-cutting ant Acromyrmex balzani on CO₂ emissions in a coastal area of Northeast Brazil. Results show that A. balzani nests emitted up to four times more CO₂ than the surrounding soil and emissions were positively correlated with soil moisture and soil organic matter (SOM) content. In addition, field experiments demonstrated that refuse material has a lower residence time than the leaf material brought to the colonies. Despite the high density of nests and high content of SOM compared to adjacent control soil, CO₂ emissions by A. balzani nests represent only 0.3% of the total CO₂ efflux by the studied ecosystem. Although these effluxes account for a relative small portion of the total soil CO₂ emission, they are still important for the understanding of C balance, especially when one considers the thousands of tons of CO₂ emitted each day, across entire Neotropical regions where leaf-cutting ants occur.     

Adsorption Kinetics of Blue 5G Dye from Aqueous Solution on Dead Floating Aquatic Macrophyte: Effect of pH, Temperature, and Pretreatment

The textile industry is known to generate large quantities of effluents contaminated with dyes that are not fixed to the fibers during the dyeing process. The available technologies to remove these dyes from the wastewater are expensive and ineffective. Within this context, low-cost, easy-maintenance technologies for the removal of dyes have been studied, such as adsorption on aquatic macrophytes. Thus, the macrophyte Salvinia sp., raw or pretreated with NaOH or H₃PO₄, was used as biosorbent of Blue 5G reactive dye. The study showed that pH and temperature affect the dye removal capacity. The analysis of the infrared spectrum (FTIR) showed that chemical treatment of the Salvinia sp. modified the biomass surface and affected dye adsorption capacity. The pseudo-second-order kinetic model satisfactorily described the experimental data for raw and NaOH-pretreated biomass, and the pseudo-first-order model was more appropriate to describe the experimental data obtained with H₃PO₄-pretreated biomass. The highest capacity of Blue 5G dye removal was obtained with raw biomass, at 333?K and pH?1.0, with 98.35?% adsorption.     

Growth performance of Nile tilapia,Oreochromis niloticus,fed diets containing levels of pyridoxine and haematological response under heat stress

In order to assess the effect of dietary pyridoxine supplementation on the growth performance of Nile tilapia and the haematological response under heat stress, 192 fingerlings (8.41 ± 0.22 g) were randomly distributed into eight tanks and fed practical diets supplemented with increasing levels of pyridoxine (0.0; 5.0; 10.0 and 20.0 mg of pyridoxal HCl kg^?1 diet) for 91 days. The fish were then weighed and the diet was quantified to determine the growth performance [weight gain (WG), feed intake, feed conversion ratio, protein efficiency rate, protein retention (PR) and survival percentage]. Haematological analyses (red blood cell count, haematocrit, haemoglobin, total leucocyte and differentiation, mean corpuscular volume, mean corpuscular haemoglobin concentration, albumin, globulin and albumin/globulin ratio) were carried out and then 32 fish were transferred and subjected to heat stress (32 °C) for 3 days, after which the haematological parameters were analysed. The fish fed the unsupplemented diet showed the lowest WG and PR. For the normal growth and health of the Nile tilapia, the Pyridoxine requirement in a practical diet is 10.0 mg of pyridoxine HCl kg^?1.     

Circadian polymorphisms associated with affective disorders

Background  

Clinical symptoms of affective disorders, their response to light treatment, and sensitivity to other circadian interventions indicate that the circadian system has a role in mood disorders. Possibly the mechanisms involve circadian seasonal and photoperiodic mechanisms. Since genetic susceptibilities contribute a strong component to affective disorders, we explored whether circadian gene polymorphisms were associated with affective disorders in four complementary studies.     

Diversity and identification of fungi associated with needles of Pinus radiata in Tasmania

Needle fungi have been extensively studied in conifers but rarely in Pinus radiata. Previous studies of P. radiata have been based on fungal isolation and not direct PCR detection from needles. This research was a component of a study examining factors linked to spring needle cast (SNC) in Tasmanian P. radiata plantations and aimed to identify as many as possible of the fungal species commonly associated with P. radiata needles in Tasmanian plantations. Needle samples were collected from 13 sites representative of the range of sites in which P. radiata is grown in Tasmania. Fungi were detected by a direct PCR approach and identified using barcode sequences from a reference collection of isolates from Tasmania, mainland Australia and New Zealand as well as sequences from the international nucleotide sequence databases. The total number of molecular operational taxonomic units (MOTUs) was 152, with 127 detected by direct PCR and sequencing, and only 35 operational taxonomic units (OTUs) isolated by culture-based methods. Dothideomycetes was the most diverse class detected in this study, with many MOTUs detected by direct PCR and not isolated. Leotiomycetes was the second-most diverse class and Sordariomycetes third, with several OTUs frequently isolated but rarely or not at all detected by direct PCR. DNA sequence data facilitated the discrimination and identification of OTUs, but some effort was required to avoid confusion caused by poorly identified isolates in public DNA databases. This is the most comprehensive study yet of fungi associated with pine needles in Australia and highlights the hitherto unrecognised diversity of Teratosphaeriaceae in P. radiata.     

Biofumigation potential of Brassicaceae cultivars to Verticillium dahliae

The biofumigation potential of brassicaceous green manures to Verticillium dahliae was systematically assessed. In a toxicological study, five different isothiocyanates (ITCs) were tested using a bioassay with sterile quartz sand artificially infested with microsclerotia. For 2-propenyl ITC, a LD₉₀ value of 88.7 nmol g^?1 was determined. Furthermore, 2-propenyl ITC with a dose of 150 nmol g^?1 soil was tested in 22 naturally infested soils. The efficiency varied from 9 % to 92 % and was negatively correlated with the organic carbon content of the soils, indicating that in many soils much higher concentrations will be necessary to achieve sufficient control. To evaluate the biofumigation potential of different Brassicaceae, 19 cultivars of Brassica juncea, Rhaphanus sativus and Sinapis alba were grown in the field. Biomass production was measured and glucosinolate concentrations were analyzed. Simulating the field situation, the biofumigation effect of cultivars was assessed in a standardized laboratory bioassay with microsclerotia-infested sterile quartz sand amended with freeze-dried ground plant tissues. Amendments of B. juncea shoot tissue reduced the number of viable microsclerotia significantly with efficiencies from 69.3 to 81.3 %. Total potentially released amounts of 2-propenyl ITC ranged between 50.6–78.1 nmol g^?1sand and indicate a clear ITC-related suppression. However these are considered too low for effective control in practice as low release efficiencies mean that effective levels fall well short of the estimated 150 nmol g^?1 of soil required. In comparison with B. juncea, the R. sativus and S. alba were less effective due to lower concentrations and/or toxicity of the ITC released. In summary, the biofumigation potential of the cultivars tested appears insufficient alone for effective control, especially on soils with higher (>1.0 %) organic carbon content.