Women's most common menstrual product is sanitary pads. Most disposable sanitary pads are constructed of up to 90% non-biodegradable plastics and bleached wood pulp. Throughout the sanitary pad's life cycle, there is a risk of exposure to toxic emissions harmful to humans and ecosystems. In contrast, disposable sanitary pads' health and environmental consequences have received little attention due to cultural stigma associated with menstruation and a lack of information regarding the chemical components used in sanitary pads. A case study has been performed at the Hempur company in Stockholm, Sweden, to evaluate potential environmental impacts of a sanitary disposal pad made almost entirely of unbleached bamboo pulp and polylactic plastic (PLA). The study's objectives were accomplished using a comparative life cycle assessment methodology to identify potential trade-offs between Hempur disposable sanitary pads and a conventional disposable sanitary pad consisting of non-biodegradable polymers and bleached wood pulp. Thus, understanding the study's results allows the implementation of recommendations to improve the environmental performance of Hempur sanitary pads. The study results indicate that Hempur plant-based sanitary pads, even though shipped to Sweden from China, have lower adverse environmental impacts —on average 40% less than conventional sanitary pads created using traditional materials and manufacturing sites in European countries. More than 80% of the overall impacts of the conventional sanitary pad were attributed to bleached wood pulp and low-density polyethylene. The upstream operations of Hempur sanitary pads were identified as the least environmentally friendly phase of the product due to the use of unbleached wood pulp and polylactic plastic, which together account for between 40% and 80% of all impact categories, most notably water scarcity and abiotic element depletion. Other factors and assumptions identified during the sensitivity analysis suggested the potential for reducing the environmental footprint of Hempur sanitary pads. By transitioning from coal to hydropower to generate electricity for bamboo pulp manufacturing, Hempur's upstream operations will dramatically improve their environmental performance, resulting in a reduction in global warming and acidification. Finally, this study suggests that other alternatives for PLA and use bamboo in the core part of Hempur sanitary pad should be considered and assessed. In this study, however, parts of the life cycle inventory process were omitted due to a lack of data on the materials and process method, which may affect the precision of the results.

O objetivo deste trabalho foi produzir poli-3-hidroxibutirato (P3HB) e poli-3-hidroxibutirato-co-3-hidroxivalerato (PHB-co-3HV), polímeros biodegradáveis, utilizando hidrolisado hemicelulósico, rico em xilose, de bagaço de cana-de-açúcar. O estudo dos fluxos metabólicos de xilose in silico indicou que, através do redirecionamento do metabolismo, é possível aumentar o rendimento P3HB a partir de xilose de 0.25 g g-1 para 0.40 g g-1. Obtiveram-se mutantes no sistema repressão catabólica nos quais se verificaram consumo simultâneo de carboidratos e redução do tempo de consumo dos açúcares. Porém, diferenças de fluxos de carbono resultaram em menores valores de crescimento e produção de PH3B em relação às linhagens parentais. Um programa de bioprospecção destacou Burkholderia sp. F24, em experimentos em biorreator obteve-se 25.04 g l-1 de biomassa, 49.31% de acúmulo de P3HB na massa seca celular, alcançando uma produtividade de 0.28 g l-1 h-1. Além disso, foi possível controlar a fração molar de 3HV na síntese PHB-3HV em F24 utilizando xilose e ácido levulínico. / The aim of this thesis is to produce poly3-hydroxybutyrate (P3HB) and poli-3-hidroxibutirate-co-3-hydroxyvalerate (PHB-co-3HV), biodegradable polymers, using hemicellulosic hydrolysate, rich in xylose, from sugarcane bagasse. Metabolic flux analysis in silico of xylose metabolism indicated that, though metabolism redirection is possible to increase P3HB yield from 0.25 g g-1 to 0.40 g g-1. It was observed simultaneous consumption of sugars and reduction of time necessary to exhaust of all sugars in the media culture in mutants with catabolite repression partially abolished. However, differences in carbon flux resulted in lower growth and P3HB production in comparison to the parental strain. A bioprospecting program selected Burkholderia sp. F24, in experiments in bioreactor it reached 25.04 g l-1, 49.31% of P3HB accumulation of the dry cell mass and 0.28 g l-1 h-1 of productivity. Moreover, it was possible to modulate to molar fraction of 3HV in PHB-co-3HV biosyntheses with Burkholderia sp. F24 using xylose and levulinic acid.

O objetivo deste trabalho foi produzir poli-3-hidroxibutirato (P3HB) e poli-3-hidroxibutirato-co-3-hidroxivalerato (PHB-co-3HV), polímeros biodegradáveis, utilizando hidrolisado hemicelulósico, rico em xilose, de bagaço de cana-de-açúcar. O estudo dos fluxos metabólicos de xilose in silico indicou que, através do redirecionamento do metabolismo, é possível aumentar o rendimento P3HB a partir de xilose de 0.25 g g-1 para 0.40 g g-1. Obtiveram-se mutantes no sistema repressão catabólica nos quais se verificaram consumo simultâneo de carboidratos e redução do tempo de consumo dos açúcares. Porém, diferenças de fluxos de carbono resultaram em menores valores de crescimento e produção de PH3B em relação às linhagens parentais. Um programa de bioprospecção destacou Burkholderia sp. F24, em experimentos em biorreator obteve-se 25.04 g l-1 de biomassa, 49.31% de acúmulo de P3HB na massa seca celular, alcançando uma produtividade de 0.28 g l-1 h-1. Além disso, foi possível controlar a fração molar de 3HV na síntese PHB-3HV em F24 utilizando xilose e ácido levulínico. / The aim of this thesis is to produce poly3-hydroxybutyrate (P3HB) and poli-3-hidroxibutirate-co-3-hydroxyvalerate (PHB-co-3HV), biodegradable polymers, using hemicellulosic hydrolysate, rich in xylose, from sugarcane bagasse. Metabolic flux analysis in silico of xylose metabolism indicated that, though metabolism redirection is possible to increase P3HB yield from 0.25 g g-1 to 0.40 g g-1. It was observed simultaneous consumption of sugars and reduction of time necessary to exhaust of all sugars in the media culture in mutants with catabolite repression partially abolished. However, differences in carbon flux resulted in lower growth and P3HB production in comparison to the parental strain. A bioprospecting program selected Burkholderia sp. F24, in experiments in bioreactor it reached 25.04 g l-1, 49.31% of P3HB accumulation of the dry cell mass and 0.28 g l-1 h-1 of productivity. Moreover, it was possible to modulate to molar fraction of 3HV in PHB-co-3HV biosyntheses with Burkholderia sp. F24 using xylose and levulinic acid.

Combinatorial techniques, which overcome limitations of actual models of material research permitting to effectively address this large amount of variables, are utilized in this work to prepare combinatorial libraries of the blend of the biodegradable polymers Poly(e-caprolactone) and Poly(lactic acid). These libraries present continuous composition and temperature gradients in an orthogonal fashion that permit to obtain multiple surface morphologies with controllable microstructures due to the blends low critical solution phase behavior (LCST). The goal of this study is to investigate the effect of surface morphology (surface chemical patterning and surface topography) on cell behavior. The varied surface topography of the libraries is used as a valuable tool that permits to assay the interaction between MC3T3-E1 cells and hundreds of different values of critical surface properties, namely, surface roughness and microstructure size. The outcome of this tool is a rapid screening of the effect of surface topography on cell behavior that is orders of magnitude faster than the standard 1-sample for 1 measurement techniques. The results obtained show that cells are very sensitive to surface topography, and that the final effect of surface properties on cell function is intimately related with the stage of the cell developmental process. Meaning that, for example, areas with optimal characteristics to elicit enhancement of cell attachment is not necessarily the same that promotes cell proliferation. This study imparts an improved understanding of an often neglected factor in biomaterials performance: surface morphology (particularly surface topography). The results provide a new insight into the importance of taking into consideration both chemistry and physical surface features for superior biomaterial design.

科学研究費補助金 研究種目:一般研究(C) 課題番号:05650796 研究代表者:山根 恒夫 研究期間:1993-1994年度