ABSTRACT
Production of 2,3-butanediol (2,3-BD) by Pantoea agglomerans strain BL1 was investigated using soybean hull hydrolysate as substrate in batch reactors. The cultivation media consisted of a mixture of xylose, arabinose, and glucose, obtained from the hemicellulosic fraction of the soybean hull biomass. We evaluated the influence of oxygen supply, pH control, and media supplementation on the growth kinetics of the microorganism and on 2,3-BD production. P. agglomerans BL1 was able to simultaneously metabolize all three monosaccharides present in the broth, with average conversions of 75% after 48 h of cultivation. The influence of aeration conditions employed demonstrated the mixed acid pathway of 2,3-BD formation by enterobacteria. Under fully aerated conditions (2 vvm of air), up to 14.02 g L-1 of 2.3-BD in 12 h of cultivation were produced, corresponding to yields of 0.53 g g-1 and a productivity of 1.17 g L-1 h-1, the best results achieved. These results suggest the production potential of 2,3-BD by P. agglomerans BL1, which has been recently isolated from an environmental consortium. The present work proposes a solution for the usage of the hemicellulosic fraction of agroindustry biomasses, carbohydrates whose utilization are not commonly addressed in bioprocess.
Subject(s)
Bioreactors , Butylene Glycols/metabolism , Glycine max/chemistry , Pantoea/growth & developmentABSTRACT
Envelope insulation and protection is an important technical solution to reduce energy consumption, exterior damage, and environmental impacts in buildings. Thermal insulation tiles are used simultaneously as thermal insulation of the building envelope and protection material of under layers in flat roofs systems. The purpose of this research is to assess the environmental impacts of the life cycle of thermal insulation tiles for flat roofs. This research presents the up-to-date "cradle to gate" environmental performance of thermal insulation tiles for the environmental categories and life-cycle stages defined in European standards on environmental evaluation of building. The results presented in this research were based on site-specific data from a Portuguese factory and resulted from a consistent methodology that is here fully described, including the raw materials extraction and production, and the modelling of energy and transport processes at the production stage of thermal insulation tiles. These results reflect the weight of the raw-materials within the production process of thermal insulation tiles in all environmental categories and show that some life cycle stages, such as transportation of raw materials (A2) and packaging and packaging waste (A3.1 and A3.3, respectively), may not be discarded in a cradle to gate study of a construction material because they can make a significant contribution to some environmental categories. Moreover, complementary results regarding the economic, environmental, and energy performance Life Cycle Assessment (LCA) of flat roofs solutions incorporating the thermal insulation tiles studied showed that the influence of the economic costs on the total aggregated costs of these solutions is much higher than that of the environmental costs due to the lower environmental costs of the thermal insulation tiles at the product stage (A1-A3). These costs influenced the corresponding percentage of the environmental costs (between 14% and 18%) and the percentage of the economic costs (between 70% and 75%) in the total aggregated (environmental, economic, and energy) net present value (NPV). Finally, a complementary "cradle to cradle" environmental LCA discussion is presented including the following additional life cycle stages: maintenance and replacement (B2-B4), operational energy use (B6), and end-of-life stage and benefits and loads beyond the system boundary (C1-C4 and D).
ABSTRACT
O soro de leite fermentado pela levedura Kluyveromyces fragilis, após secagem em spray drier, foi submetido à avaliaçäo da qualidade protéica através de uma análise aminoacídica e de um estudo biológico pelos métodos: Relaçäo da eficiência Protéica (PER), Relaçäo da Eficiência Líquida da Proteína (NPR) e Utilizaçäo Líquida da Proteína (NPU). Na análise aminoacídica, foram utilizadas como comparativo a composiçäo de aminoácidos das proteínas padräo do ovo e da FAO. Os resultados indicaram um alto nível de lisina (65,60mg/g de proteína) e baixos níveis de metionina e valina, respectivamente, 14,90mg e 45,80mg/g de proteína. A avaliaçäo biológica foi conduzida durante 4 semanas, sendo utilizados 24 ratos desmamados aos 23 dias de idade. Os resultados para PER, NPR e NPU foram respectivamente, 19,75 por cento, 46,33 por cento e 26,54 por cento comparados com os valores obtidos com a proteína padräo caseína. A qualidade da proteína do soro seco fermentado apresentou-se inferior à proteína da caseína.
