CHARACTERIZING AND PREDICTING THE ANTIMICROBIAL PROPERTIES OF LIGNIN DERIVATIVES

Due to the overuse of antibiotics in our society, there has been a steady rise in highly antimicrobial-resistant bacteria in the last decade. This has created a renewed interest in natural phenolic compounds for antimicrobial discovery amongst the scientific community. To this end, lignin is the most abundant naturally occurring phenolic polymer on earth and has already been known to have antimicrobial properties due to its polyphenolic structure. In addition, lignin is considered a major waste product for lignocellulosic biorefineries, and its valorization into value-added products will generate extra profit for a biorefinery, making biofuels less expensive, increasing their marketability as an alternative to fossil fuels. However, the retention of lignin’s antimicrobial properties in different materials, as depolymerized products, or even the prediction of their antimicrobial properties is not well understood in the literature. Much work has utilized lignin as a functional polymer in a variety of composites and materials, but their antimicrobial properties have not been as widely explored. Therefore, ionic liquids were used in the facile preparation of cellulose-based hydrogels, and the addition of different lignocellulosic components (lignin and xylan) or the use of whole biomass (poplar and sorghum) were evaluated for their effects on hydrogel properties (mechanical and antimicrobial). The addition of both lignin and xylan improved hydrogel mechanical strength/stiffness, and lignin-containing hydrogels showed retained antimicrobial properties when screened against the target organism (Escherichia coli). Utilizing raw biomass provided increased mechanical strength (poplar), similar water retention abilities (poplar and sorghum), and retained antimicrobial properties (poplar). These results indicate that the different components of lignocellulose can be used to fine tune the properties of cellulose-based hydrogels and that lignin can confer its antimicrobial properties when incorporated into hydrogels. The antimicrobial properties of different lignin depolymerization products were explored using a reductive and oxidative depolymerization method to produce phenolic rich lignin-based bio-oils. Purified alkali-enzymatic corn stover lignin (AEL) was depolymerized by catalytic transfer hydrogenolysis using supercritical ethanol and a Ru/C catalyst, generating a bio-oil stream at high yields. Sequential extraction was used to fractionate the bio-oil into five fractions with different phenolic compositions using hexane, petroleum ether, chloroform, and ethyl acetate. Antimicrobial properties of the bio-oils were screened against Gram-positive/negative bacteria and yeast by examining microbial growth inhibition. The monomers in the bio-oil fractions contained primarily alkylated phenols, hydrogenated hydroxycinnamic acid derivatives, syringol and guaiacol-type lignins created from reductive cleavages of ether linkages. After sequential extraction, the lignin derived compounds were fractionated into groups depending on solvent polarity. Results suggest that the total monomer concentration and the presence of specific monomers (i.e., syringyl propane) may correlate to the antimicrobial activity of lignin depolymerization products, but the exact mode of action or antimicrobial activity caused by the complex mixtures of monomers and unidentified oligomers remains unclear. The same AEL lignin was depolymerized through oxidative procedures using peracetic acid, and its applications as an antibiotic replacement in the fuel ethanol industry were explored. The resulting bio-oil had a low degree of depolymerization that mostly produced unidentifiable lignin oligomers. Nonetheless, this bio-oil displayed highly selective antimicrobial properties, with up to 90% inhibition of commercially sampled lactic acid bacteria (LAB) at 4 mg/ml and no inhibition of yeast. Using the bio-oil (4 mg/ml) as an alternative antibiotic treatment during simultaneous-saccharification and fermentation of raw corn starch showed an 8% increase in ethanol production at a yeast to LAB ratio of 1:100, compared to untreated contaminated controls. The ability of the bio-oil to improve ethanol yields clearly shows its efficacy as an alternative antibiotic and that depending on depolymerization method lignin derivates can display a variety of useful antimicrobial properties/applications. The final study was the first attempt in the literature to predict the antimicrobial properties of lignin derivatives using quantitative structure−activity relationship (QSAR) models. First, the open-access database ChEMBL, with non-lignin specific compounds, was used to create datasets of compounds with MIC activity measurements against both B. subtilis and E. coli. Machine learning algorithms were used to develop the QSARs for the large ChEMBL datasets and were found to underpredict the antimicrobial activity of actual lignin compounds. Conversely, as metanalysis of the literature containing MIC data of lignin derivatives were used to build QSAR models with ordinary least square regressions (OLS). An accurate QSAR model for E. coli was not found, but a satisfactory model was obtained for the B. subtilis metanalysis dataset. Molecular Operation Environment (MOE)-type descriptors and the number of aliphatic carboxylic acid groups showed strong correlations to the MIC values (R2 of 0.759). Comparatively, an additional dataset was experimentally derived by screening 25 lignin monomers and three dimers against B. subtilis by measuring bacterial load difference (BLD). This datasets QSAR, using OLS, found that MOE-type descriptors and the number of aromatic hydroxyl groups were better predictors of BLD (R2 of 0.831). Thus, the smaller datasets highlighted how the variability in antimicrobial measurements and the specific compounds used will impact the predictive nature of the resulting QSARs. Overall, this entire work provides critical knowledge and guidance on using lignin as an antimicrobial source in different industrial processes/products and the identification of lignin derivatives with enhanced activity

White-Rot Fungi as Pretreatment Agents for Wood Destined for Biofuel Applications

Efficient and economical conversion of lignocellulosic biomass to biofuels is often hampered by the chemical recalcitrance of the material. Inexpensive and environmentally-friendly pretreatment processes are therefore desirable in order to lower the cost of biofuel production and minimize negative environmental impacts. To that end, we have explored the use of a naturally occurring white-rot fungus, Trametes versicolor, as a direct pretreatment agent for hardwood destined for biofuel applications. Specifically, we examined the pretreatment effects on the hardwood mixture after treatment with the wild-type strain of T. versicolor (52J) compared with those from a cellobiose dehydrogenase (CDH)-deficient strain (m4D) , to examine how a lack of CDH affects wood pretreatment. The effects of each strain of T. versicolor on the lignocellulose chemistry within the wood were examined after 12 weeks of incubation, as well as the physicochemical properties (pellet strength and energy content). At the laboratory scale, pretreatment with the mutant strain showed altered lignin structure and improved sugar yields, while the wild-type strain led to substantially increased pellet strength without impeding the overall energy content of the pellets. However, at the demonstration scale (150 L), the wild-type strain did not alter pellet strength, despite similar lignin extraction characteristics, glucose content, and energy content when compared to the laboratory scale. Therefore, further research will need to be conducted at the laboratory and demonstration scales to investigate how this fungus alters the structure of lignocellulose at the biochemical level (e.g., transcriptomic analysis), and how fungal pretreatment may affect other biofuel technologies, such as biomass gasification

White-Rot Fungi as Pretreatment Agents for Wood Destined for Biofuel Applications

Efficient and economical conversion of lignocellulosic biomass to biofuels is often hampered by the chemical recalcitrance of the material. Inexpensive and environmentally-friendly pretreatment processes are therefore desirable in order to lower the cost of biofuel production and minimize negative environmental impacts. To that end, we have explored the use of a naturally occurring white-rot fungus, Trametes versicolor, as a direct pretreatment agent for hardwood destined for biofuel applications. Specifically, we examined the pretreatment effects on the hardwood mixture after treatment with the wild-type strain of T. versicolor (52J) compared with those from a cellobiose dehydrogenase (CDH)-deficient strain (m4D) , to examine how a lack of CDH affects wood pretreatment. The effects of each strain of T. versicolor on the lignocellulose chemistry within the wood were examined after 12 weeks of incubation, as well as the physicochemical properties (pellet strength and energy content). At the laboratory scale, pretreatment with the mutant strain showed altered lignin structure and improved sugar yields, while the wild-type strain led to substantially increased pellet strength without impeding the overall energy content of the pellets. However, at the demonstration scale (150 L), the wild-type strain did not alter pellet strength, despite similar lignin extraction characteristics, glucose content, and energy content when compared to the laboratory scale. Therefore, further research will need to be conducted at the laboratory and demonstration scales to investigate how this fungus alters the structure of lignocellulose at the biochemical level (e.g., transcriptomic analysis), and how fungal pretreatment may affect other biofuel technologies, such as biomass gasification

Spectral Sensitivity, Luminous Sensitivity, and Temporal Resolution of the Visual Systems in Three Sympatric Temperate Coastal Shark Species

We used electroretinography (ERG) to determine spectral and luminous sensitivities, and the temporal resolution (flicker fusion frequency, FFF) in three sympatric (but phylogenetically distant) coastal shark species: Carcharhinus plumbeus (sandbar shark), Mustelus canis (smooth dogfish), and Squalus acanthias (spiny dogfish). Spectral sensitivities were similar (range ~400–600 nm, peak sensitivity ~470 nm), with a high likelihood of rod/cone dichromacy enhancing contrast discrimination. Spiny dogfish were significantly less light sensitive than the other species, whereas their FFF was ~19 Hz at maximum intensities; a value equal to that of sandbar shark and significantly above that of smooth dogfish (~9–12 Hz). This occurred even though experiments on spiny dogfish were conducted at 12 versus 25 °C and 20 °C for experiments on sandbar shark and smooth dogfish, respectively. Although spiny dogfish have a rod-dominated retina (rod:cone ratio 50:1), their visual system appears to have evolved for a relatively high temporal resolution (i.e., high FFF) through a short integration time, with the requisite concomitant reduction in luminous sensitivity. Our results suggest adaptive plasticity in the temporal resolution of elasmobranch visual systems which reflects the importance of the ability to track moving objects such as mates, predators, or prey

O genoma humano como bem integrante do patrimônio ambiental natural

Orientador: José Antônio Peres GedielMonografia (graduação) - Universidade Federal do Paraná, Setor de Ciências Jurídicas, Curso de DireitoO presente trabalho objetivou demonstrar a possibilidade de incidência das normas de direito ambiental sobre o bem 'genoma humano', tendo como premissa sua inclusão no rol dos bens integrantes do patrimônio ambiental natural. Faz-se, para tanto, uma análise das representações da relação homem-natureza predoderamente encontradas nas civilizações ocidentais desde os gregos até nossos dias, uma vez que a concepção de natureza (e conseqUentemente de meio ambiente) é influenciada da regulação a ser conferida aos bens jurídicos que a integram. Advoga-se a necessidade de um superação qualitativa tanto do antropocentrísmo clássico, como do biocentrismo, recaindo-se no chamado antropocentrismo alargado, que por sua vez, é capaz de assimilar novos valores antes alheios às discussões ambientais, como a noção de sustentabilidade e de geração futura, bem como reconhecer a dependência do homem em face do meio ambiente (e sua caracteristica de ser integrante de uma realidade natural mais ampla). A partir dessa nova postura do homem frente ao meio ambiente, possibilita-se a construção de uma concepção ampla e holística de meio ambiente, que nos permite (apoiando-se na análise da doutrina brasileira de direito ambiental e da normatividade potitivada no ordenamento jurídico nacional) incluir o genoma humano como elemento integrante da categoria 'patrimonio ambiental natural'. Discorre-se acerca dos regimes jurídicos incidentes sobre esse 'novo' bem ambiental: por um lado, alude-se à possibilidade de sujeição do genoma humano às normas dos direitos da personalidade, a fim de se tutelar a esfera individual dos seres humanos ( direito à intimidade, ao próprio corpo, à identidade...) e por outro lado, sugere-se a sujeição do genoma humano, quando estiver sendo focalixado seu aspecto comunitário (capaz de dizer respeito à toda a espécie humana), às normas de direito ambiental, com o intuito de se promover uma adequada e completa tutela jurídica desse bem, atribuindo ao ser humano um mínimo normativo natural

Evolução da colaboração na cadeia de suprimentos : o modelo proposto pelo CPFR

Orientador: Darli Rodrigues VieiraMonografia(Especialização) - Universidade Federal do Paraná,Setor de Ciências Sociais Aplicadas, Curso de Especialização em Gerência de Sistemas Logístico