The effect of agitation speed, enzyme loading and substrate concentration on enzymatic hydrolysis of cellulose from brewer’s spent grain

Brewer’s spent grain components (cellulose, hemicellulose and lignin) were fractionated in a two-step chemical pretreatment process using dilute sulfuric acid and sodium hydroxide solutions. The cellulose pulp produced was hydrolyzed with a cellulolytic complex, Celluclast 1.5 L, at 45 ºC to convert the cellulose into glucose. Several conditions were examined: agitation speed (100, 150 and 200 rpm), enzyme loading (5, 25 and 45 FPU/g substrate), and substrate concentration (2, 5 and 8% w/v), according to a 2 3 full factorial design aiming to maximize the glucose yield. The obtained results were interpreted by analysis of variance and response surface methodology. The optimal conditions for enzymatic hydrolysis of brewer’s spent grain were identified as 100 rpm, 45 FPU/g and 2% w/v substrate. Under these conditions, a glucose yield of 93.1% and a cellulose conversion (into glucose and cellobiose) of 99.4% was achieved. The easiness of glucose release from BSG makes this substrate a raw material with great potential to be used in bioconversion processes.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo), Brazil. Novozymes ( FAPESP )Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

Pesticides Removal Using Actinomycetes and Plants

The γ-hexachlorocyclohexane (γ-HCH, lindane) is an organochlorine pesticide used in agriculture and medicine to world level. It has a big tendency to bioaccumulation into the environment so is listed as a priority pollutant by the US EPA. Hence the development of new technologies to remediate these sites using microorganisms is every time more necessary. The actinomycetes are Gram-positive bacteria with great potential to bioremediate xenobiotics. One strain, Streptomyces sp. M7, isolated from organochlorine pesticide contaminated sediment, was selected for its capacity to grow in presence of lindane as only carbon source. This microorganism was cultured in soil extract medium added of lindane 100 μg L−1, obtaining a maximal growth of 0.065 mg mL−1, similar to the control, with a highest lindane remotion of 70.4 % at 30°C and pH 7. When different initial pesticide concentrations (100, 150, 200, and 300 μg L−1) were added in soil medium, an increment of the microbial growth was detected in all the concentrations tested. Also a diminution of the residual lindane concentration was determined in the soil samples in relation to controls without bacteria (29.1, 78.0, 38.8, and 14.4 %, respectively). Besides, it was determined the optimum Streptomyces sp. M7 inoculum when lindane 100 μg kg−1soil was added to the soil sample. The optimum inoculum was 2 g kg−1 soil for obtaining the most efficiently bioremediation process: the lindane removal in these conditions was 67.8 % at 28 days of incubation. Later it was considered necessary to know the pesticide effects on maize plants seeded in lindane-contaminated soil previously inoculated with Streptomyces sp. M7. Lindane concentrations of 100, 200, and 400 mg kg−1 soil did not affect the germination and vigor index of maize plants seeded in contaminated soils without Streptomyces sp. M7. When this microorganism was inoculated at the same conditions, a better vigor index was observed and 68 % of lindane was removed. In this connection, Streptomyces sp. M7 was grown on culture medium in presence of root exudates of maize, spiked with 1.66 mg L−1 of lindane. The highest level of pesticide removal obtained on this condition suggests that root exudates enhanced removal of lindane by the bacterium. On the other hand, little information is available on the ability of biotransformation of organochlorine pesticides by actinomycete strains. It was demonstrated that Streptomyces sp. M7 possesses the LinA enzyme that catalyzes dehydrochlorination of lindane to 1,3,4,6-tetrachloro-1,4-cyclohexadiene (1,4-TCDN) via γ-pentachlorocyclohexene (γ-PCCH). These results confirm that actinomycete strains could be considered one of the most promising bacterial groups for lindane biodegradation in contaminated environment. Particularly, Streptomyces sp. M7 could be used for this purpose.Fil: Alvarez, Analia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; ArgentinaFil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin