Doctor of Philosophy / Department of Grain Science and Industry / Yong Cheng Shi / Wheat bran is a by-product of the wheat flour milling industry. The number of food products containing wheat bran is on the rise because it is a well-recognized good source of dietary fiber. Currently, bran is a low-value commodity used mostly in animal feed, but it has the potential for more extensive applications. To understand the functional and nutritional properties of wheat bran and better use wheat bran in food, it is critical to understand the physical structure of wheat bran. For the first time, solid-state ¹³C cross-polarization magic-angle spinning nuclear magnetic resonance (¹³C CP/MAS NMR), X-ray diffraction (XRD), and small angle X-ray scattering (SAXS) were used to study the physical structure of wheat bran and its dissected layers. The XRD and Solid-State ¹³C CP/MAS NMR both confirmed the presence of crystalline cellulose in untreated bran, enzymatically treated bran, and dissected bran layers. Destarched and deproteinized wheat bran (DSDPB) was treated with a mixture of either 7 or 9% sodium hydroxide and 12% urea solvent and structure of the extracted polymers was investigated. Three and 6 cycle dissolution schemes, were examined involving the repeated cooling of the solvent bran mixture to -12.6 °C and then agitating it at 25 °C. When 7% NaOH/12% urea (6 cycle) was applied to DSDPB, 84.1% of the material was solubilized including 89.8% of the arabinoxylans (AX). This procedure recovered more wheat bran AX for characterization than any previous study using alkaline dissolution. Wheat bran was enzymatically and hydrothermally treated to maximize the soluble fraction. Unlike previous research, the starch and protein were kept and not removed before endoxylanase treatment. The retained protein and glucose polymers (starch, β-glucan, cellulose) could provide functional benefits in addition to the arabinoxylan and could make the process more economical. Wheat bran hydrolyzed with thermostable α-amylase, protease, and xylanase was the recommended treatment. The combined solubles had a viscosity of 23 cP (10% w/w solids) and ranged in estimated molecular weight from ~600 to 20,000. The percentage of untreated wheat bran AX that was solubilized was 50% and the percentage of AX in the solubles was 23%.

In this diploma thesis has been studied system of hydrogels based on interaction between polyelectrolyte and surfactants, especially their solubilizing properties. As a surfactant was used ionic cationic cetyltrimethylammonium bromide (CTAB). As a polyelectrolyte was chosen native anionic hyaluronan with various molecular weight - 0,3; 0,9; 1,6 MDa and with different concentration - 2%, 4%, 6% wt. Solubilization experiments were realized with hydrophobic dye sudan red G. The whole system was prepared in the simpliest model system of physiological solution 0,15 M NaCl and in water. At the prepared gels was investigated their stability, influence of the environment, molecular weight and concentration on solubilization. Gels were prepared in rate hyaluronan-surfactant 1:1. The purpose of this diploma thesis was to find and optimize the appropriate procedure for determining solubilization capacity by using UV-VIS spectrophotometry.

Orientador: Jackson Antônio Marcondes de Souza / Banca: Eduardo da Silva Martins / Banca: Natália Vinhal Grupioni / Resumo: Os microrganismos têm participação ativa nas transformações do fósforo (P) no solo, influenciando sua disponibilidade para as plantas e seu fluxo na natureza. As transformações resultam de decomposição e mineralização de compostos orgânicos, imobilização na microbiomassa e solubilização das formas inorgânicas dos minerais. A base desse estudo consistiu em avaliar 10 isolados bacterianos, visando caracterizá-los quanto: padrão de crescimento em meio Tryptone Yeast (TY) (padrão de crescimento em meio NBRIP (National Botanical Research Institute's Phosphate); solubilização de fosfato de hidróxido de cálcio (Ca5OH(PO4)3); variação do pH nos diferentes meios; sequenciamento parcialmente do gene 16S rRNA, e influência do crescimento, em casa de vegetação, para as culturas da soja (Glycine max) e milho (Zea mays). Os melhores solubilizadores em 120 h de cultivo foram os isolados LGA- 11-V0522, 33,81 mg/ml, Chromotacterium Violaceum, LGA13-V20F, 32,65 mg/ml, Arthrobacter echigonensis, LGA1-V4-V20J, 32,19 mg/ml, Arthrobacter echigonensis, e LGA05-V0513, 30,96 mg/ml, Bacilus Cereus. Em casa de vegetação, os isolados que apresentaram melhores resultados foram, com maior desenvolvimento de parte aérea, LGA13-V20F, 22,67 cm, Arthrobacter echigonensis, LGA09-V20L, 22,0 cm, Bacillus thuringiensis, LGA07-V0508, 21,25 cm, Bacillus thuringiensis, e LGA12-V05D 19,25, Bacillus thuringiensis. / Abstract: The microorganisms have an active participation in the transformations of the phosphorus (P) in the soil, influencing its availability to the plants and their flow in nature. The transformations result from decomposition and mineralization of organic compounds, immobilization in the microbiomass and solubilization of inorganic forms of minerals. The base of this study was to evaluate 10 bacterial isolates, aiming to characterize them as: growth pattern in Tryptone Yeast (TY) medium (growth pattern in NBRIP medium; solubilization of calcium hydroxide phosphate Ca5OH (PO4) 3), pH variation in the different media, partial sequencing of the 16S rRNA gene, and growth influence in the greenhouse for soybean (Glycine max) and maize (Zea mays) crops.The best solubilizers In 120 h of culture were the isolates LGA-11-V0522, 33.81 mg / ml, Chromotacterium Violaceum, LGA13-V20F, 32.65 mg / ml, Arthrobacter echigonensis, LGA1-V4-V20J, 32.19 mg / ml, Arthrobacter echigonensis, and LGA05- V0513, 30.96 mg / ml, Bacilus Cereus, and LGA13-V20F, 22.67 cm. In the greenhouse, LGA09-V20L, 22.0 cm, Bacillus thuringiensis, LGA07-V0508, 21.25 cm, Bacillus thuringiensis, and LGA12-V05D 19.25, Bacillus thuringiensis. / Mestre

The solubilities of three poorly water soluble drugs, phenytoin, diazepam and benzocaine, were measured in various cosolvent-water mixtures. The data were generally described by the relationship: log (S(m)/S(w)) = Σf₁σ₁ where S(m) is the solubility of the drug in the cosolvent-water mixture, S(w) is the solubility of the drug in water, f₁ is the volume fraction of cosolventi and σ₁ is the slope of the log(S(m)/S(w)) vs. f₁ plot. In most cases, some positive or negative deviation from the log-linear solubility equation is observed. The deviation is similar for all three drugs in many of the cosolvent-water mixtures. This suggests that the deviation is primarily due to interactions between the solvent components. However, it could not be predicted from any of the physical properties of the solvent mixtures. Changes in the solute crystal structure could not be identified as a source of nonideality. The deviations from the log-linear solubility equation may involve such factors as changes in solvent structure, hydrophobic hydration, density changes and hydrogen bonding differences between solute and cosolvent. The slopes, σ₁, of the solubilization plots were related to various indexes of solvent polarity including dielectric constant, solubility parameter, partition coefficient, surface tension and interfacial tension. The best correlations were obtained with measures of solvent cohesive forces such as interfacial tension and solubility parameter. In general, the solubilities in mixtures of aprotic cosolvents and water are higher than predicted by any of the polarity indexes. The slopes are thus related to the hydrogen bonding ability of the cosolvent as expressed by the density of proton donor and acceptor groups of the neat cosolvent. The slopes of the solubilization plots can be predicted from linear relationships with polarity indexes of the cosolvent. Therefore it is possible to estimate the slope, σ, in any cosolvent-water mixture from the solubilities in two solvents for a given drug. Furthermore, the solubility in any cosolvent water mixture can be estimated by combining the log-linear solubility equation with the estimated slopes.

Submitted by WALLYNSON EDUARDO SILVA ALMEIDA null (wallynson@yahoo.com.br) on 2017-02-24T16:09:51Z No. of bitstreams: 1 Dissertação_Wallynson_Eduardo_Silva_Almeida.pdf: 1951842 bytes, checksum: 7628e3c85a4699b4530e564dcd6cc11a (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-03-07T12:39:08Z (GMT) No. of bitstreams: 1 almeida_wes_me_jabo.pdf: 1951842 bytes, checksum: 7628e3c85a4699b4530e564dcd6cc11a (MD5) / Made available in DSpace on 2017-03-07T12:39:08Z (GMT). No. of bitstreams: 1 almeida_wes_me_jabo.pdf: 1951842 bytes, checksum: 7628e3c85a4699b4530e564dcd6cc11a (MD5) Previous issue date: 2017-01-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os microrganismos têm participação ativa nas transformações do fósforo (P) no solo, influenciando sua disponibilidade para as plantas e seu fluxo na natureza. As transformações resultam de decomposição e mineralização de compostos orgânicos, imobilização na microbiomassa e solubilização das formas inorgânicas dos minerais. A base desse estudo consistiu em avaliar 10 isolados bacterianos, visando caracterizá-los quanto: padrão de crescimento em meio Tryptone Yeast (TY) (padrão de crescimento em meio NBRIP (National Botanical Research Institute’s Phosphate); solubilização de fosfato de hidróxido de cálcio (Ca5OH(PO4)3); variação do pH nos diferentes meios; sequenciamento parcialmente do gene 16S rRNA, e influência do crescimento, em casa de vegetação, para as culturas da soja (Glycine max) e milho (Zea mays). Os melhores solubilizadores em 120 h de cultivo foram os isolados LGA- 11-V0522, 33,81 mg/ml, Chromotacterium Violaceum, LGA13-V20F, 32,65 mg/ml, Arthrobacter echigonensis, LGA1-V4-V20J, 32,19 mg/ml, Arthrobacter echigonensis, e LGA05-V0513, 30,96 mg/ml, Bacilus Cereus. Em casa de vegetação, os isolados que apresentaram melhores resultados foram, com maior desenvolvimento de parte aérea, LGA13-V20F, 22,67 cm, Arthrobacter echigonensis, LGA09-V20L, 22,0 cm, Bacillus thuringiensis, LGA07-V0508, 21,25 cm, Bacillus thuringiensis, e LGA12-V05D 19,25, Bacillus thuringiensis. / The microorganisms have an active participation in the transformations of the phosphorus (P) in the soil, influencing its availability to the plants and their flow in nature. The transformations result from decomposition and mineralization of organic compounds, immobilization in the microbiomass and solubilization of inorganic forms of minerals. The base of this study was to evaluate 10 bacterial isolates, aiming to characterize them as: growth pattern in Tryptone Yeast (TY) medium (growth pattern in NBRIP medium; solubilization of calcium hydroxide phosphate Ca5OH (PO4) 3), pH variation in the different media, partial sequencing of the 16S rRNA gene, and growth influence in the greenhouse for soybean (Glycine max) and maize (Zea mays) crops.The best solubilizers In 120 h of culture were the isolates LGA-11-V0522, 33.81 mg / ml, Chromotacterium Violaceum, LGA13-V20F, 32.65 mg / ml, Arthrobacter echigonensis, LGA1-V4-V20J, 32.19 mg / ml , Arthrobacter echigonensis, and LGA05- V0513, 30.96 mg / ml, Bacilus Cereus, and LGA13-V20F, 22.67 cm. In the greenhouse, LGA09-V20L, 22.0 cm, Bacillus thuringiensis, LGA07-V0508, 21.25 cm, Bacillus thuringiensis, and LGA12-V05D 19.25, Bacillus thuringiensis.

O aproveitamento de subprodutos da indústria sucroenergética como fonte de nutrientes para a lavoura tem-se tornado cada vez mais importante na cadeia de produção da cana-de-açúcar. Esses materiais são ricos em nutrientes, sendo ambiental e economicamente uma alternativa sustentável com vistas à ciclagem biogeoquímica. Diante disso, tais podem ser utilizados \"in natura\" ou receber tratamento, por exemplo, compostagem, que os transforma em organominerais quando da adição de fontes minerais, como o concentrado apatítico, a fim de melhorar a sua qualidade como fertilizante. Os objetivos deste estudo foram caracterizar os atributos químicos de um fertilizante organomineral, obtido por processo de compostagem com a co-utilização de bactérias solubilizadoras de fósforo, e avaliar a eficiência do mesmo na adubação em experimento conduzido em casa de vegetação. A compostagem foi conduzida em leiras no pátio da Usina São José da Estiva, localizada no município de Novo Horizonte-SP. Foram utilizados os subprodutos torta de filtro e cinza de caldeira, enriquecidos com concentrado apatítico de Araxá e esterco de poedeira. A combinação dos subprodutos propostos resultou na formação de quatro composições, distribuídas em 24 leiras de compostagem nas quais em metade delas foi adicionada uma mistura composta por bactérias dos gêneros Pseudomonas e Bacillus, com a finalidade de verificar a possibilidade de solubilização do concentrado apatítico. As leiras de compostagem foram conduzidas por 60 dias, sendo realizadas amostragens quinzenais. Foram realizadas análises químicas e físicas para caracterização dos subprodutos bem como de cada composição das leiras de compostagem. Complementarmente, foram realizadas as análises de fracionamento para identificar frações inorgânicas e orgânicas de fósforo nas composições das leiras de compostagem. A sequência de extratores utilizados foi: H2O ultrapura, NaHCO3 0,5 mol L-1, NaOH 0,1 mol L-1, HCl 1 mol L-1, NaOH 0,5 mol L-1 e MgCl2+H2SO4+H2O2 (para a digestão do resíduo). O cultivo do arroz foi conduzido em casa de vegetação, para avaliar a disponibilidade de fósforo oriundo das composições das leiras de compostagem. Os teores de macro e micronutrientes, além dos elementos benéficos e tóxicos, foram influenciados pelo período de compostagem e pela matéria-prima utilizada nas composições das leiras. As formas de fósforo presentes em todas as composições das leiras de compostagem corresponderam, principalmente, à fração de P moderadamente lábil. A adição de inoculantes à leira de compostagem promoveu solubilização do concentrado apatítico, sendo esse P incorporado nas frações orgânicas do P-lábil (P em NaHCO3 0,5 mol L-1) e do P-moderadamente lábil (P em NaOH 0,1 mol L-1). Em casa de vegetação, para o solo argiloso, o efeito do inoculante nas composições proporcionou maior teor de P acumulado pela parte aérea do arroz, provavelmente ocasionadas pela presença de formas de P com menor afinidade à fixação pelo solo. / The use of sugarcane industry waste as a source of nutrients for the crop has become increasingly important in the chain of sugarcane production. These byproducts are rich in nutrients and their use is an economical and environmentally sustainable option for waste recycling. In addition, they can be used \"fresh\" or undergo treatment such as composting. This process, when addition apatite concentrate, can transform these organic wastes into a highquality organo-mineral fertilizer. This study\'s aim was to characterize the chemical properties of an organic-fertilizer, obtained by composting process with the use of bacteria phosphate solubilizers, and to evaluate its fertilization efficiency in experiment conducted in greenhouse. Therefore, an experiment was conducted at sugarcane mill São José da Estiva composting field, located in Novo Horizonte-SP, Brazil. In the composting process, filter cake waste and boiler ash was enriched with Araxa apatite concentrate and hen manure. The combining proposed were forming four compositions distributed in 24 piles of compost. In half of the piles, a Pseudomonas and Bacillus bacteria mixture was added in order to enhance the possibility of apatite concentrate solubilization. The compost windrows ware conducted for 60 days and biweekly sampling was performed in each windrow. The chemical and physical analysis for characterization of byproducts were performed and each windrow composting composition. In addition, complementary fractionation analyzes of each sample was performed in order to identify the inorganic and organic phosphorus fractions. The sequence extraction was: ultrapure H2O, NaHCO3 0.5 mol L-1, NaOH 0.1 mol L-1, HCl 1 mol L-1, NaOH 0.5 mol L-1 and MgCl2 + H2SO4 + H2O2 for digestion residue. In order to evaluate the solubilization and availability of phosphorus from the windrow composting compositions, a greenhouse experiment with rice crop was designed. It was found that composting period and the material type influenced the nutrient and the toxic element content in all windrow composting compositions. Forms of phosphorus present in all windrow composting compositions and quantified by the fractionation mainly corresponded to the fraction of moderately labile. The inoculant addition at windrow composting promoted the solubilization of apatite concentrate and this P was incorporated in the organic fractions of labile P (NaHCO3 in 0.5 mol L-1) and moderately labile P (NaOH 0.1 mol L-1). Moreover, the bacterial inoculant increased P uptake by rice in clay soil, probably due to the formation of P forms with lower tendency of fixation in the soil.

O aproveitamento de subprodutos da indústria sucroenergética como fonte de nutrientes para a lavoura tem-se tornado cada vez mais importante na cadeia de produção da cana-de-açúcar. Esses materiais são ricos em nutrientes, sendo ambiental e economicamente uma alternativa sustentável com vistas à ciclagem biogeoquímica. Diante disso, tais podem ser utilizados \"in natura\" ou receber tratamento, por exemplo, compostagem, que os transforma em organominerais quando da adição de fontes minerais, como o concentrado apatítico, a fim de melhorar a sua qualidade como fertilizante. Os objetivos deste estudo foram caracterizar os atributos químicos de um fertilizante organomineral, obtido por processo de compostagem com a co-utilização de bactérias solubilizadoras de fósforo, e avaliar a eficiência do mesmo na adubação em experimento conduzido em casa de vegetação. A compostagem foi conduzida em leiras no pátio da Usina São José da Estiva, localizada no município de Novo Horizonte-SP. Foram utilizados os subprodutos torta de filtro e cinza de caldeira, enriquecidos com concentrado apatítico de Araxá e esterco de poedeira. A combinação dos subprodutos propostos resultou na formação de quatro composições, distribuídas em 24 leiras de compostagem nas quais em metade delas foi adicionada uma mistura composta por bactérias dos gêneros Pseudomonas e Bacillus, com a finalidade de verificar a possibilidade de solubilização do concentrado apatítico. As leiras de compostagem foram conduzidas por 60 dias, sendo realizadas amostragens quinzenais. Foram realizadas análises químicas e físicas para caracterização dos subprodutos bem como de cada composição das leiras de compostagem. Complementarmente, foram realizadas as análises de fracionamento para identificar frações inorgânicas e orgânicas de fósforo nas composições das leiras de compostagem. A sequência de extratores utilizados foi: H2O ultrapura, NaHCO3 0,5 mol L-1, NaOH 0,1 mol L-1, HCl 1 mol L-1, NaOH 0,5 mol L-1 e MgCl2+H2SO4+H2O2 (para a digestão do resíduo). O cultivo do arroz foi conduzido em casa de vegetação, para avaliar a disponibilidade de fósforo oriundo das composições das leiras de compostagem. Os teores de macro e micronutrientes, além dos elementos benéficos e tóxicos, foram influenciados pelo período de compostagem e pela matéria-prima utilizada nas composições das leiras. As formas de fósforo presentes em todas as composições das leiras de compostagem corresponderam, principalmente, à fração de P moderadamente lábil. A adição de inoculantes à leira de compostagem promoveu solubilização do concentrado apatítico, sendo esse P incorporado nas frações orgânicas do P-lábil (P em NaHCO3 0,5 mol L-1) e do P-moderadamente lábil (P em NaOH 0,1 mol L-1). Em casa de vegetação, para o solo argiloso, o efeito do inoculante nas composições proporcionou maior teor de P acumulado pela parte aérea do arroz, provavelmente ocasionadas pela presença de formas de P com menor afinidade à fixação pelo solo. / The use of sugarcane industry waste as a source of nutrients for the crop has become increasingly important in the chain of sugarcane production. These byproducts are rich in nutrients and their use is an economical and environmentally sustainable option for waste recycling. In addition, they can be used \"fresh\" or undergo treatment such as composting. This process, when addition apatite concentrate, can transform these organic wastes into a highquality organo-mineral fertilizer. This study\'s aim was to characterize the chemical properties of an organic-fertilizer, obtained by composting process with the use of bacteria phosphate solubilizers, and to evaluate its fertilization efficiency in experiment conducted in greenhouse. Therefore, an experiment was conducted at sugarcane mill São José da Estiva composting field, located in Novo Horizonte-SP, Brazil. In the composting process, filter cake waste and boiler ash was enriched with Araxa apatite concentrate and hen manure. The combining proposed were forming four compositions distributed in 24 piles of compost. In half of the piles, a Pseudomonas and Bacillus bacteria mixture was added in order to enhance the possibility of apatite concentrate solubilization. The compost windrows ware conducted for 60 days and biweekly sampling was performed in each windrow. The chemical and physical analysis for characterization of byproducts were performed and each windrow composting composition. In addition, complementary fractionation analyzes of each sample was performed in order to identify the inorganic and organic phosphorus fractions. The sequence extraction was: ultrapure H2O, NaHCO3 0.5 mol L-1, NaOH 0.1 mol L-1, HCl 1 mol L-1, NaOH 0.5 mol L-1 and MgCl2 + H2SO4 + H2O2 for digestion residue. In order to evaluate the solubilization and availability of phosphorus from the windrow composting compositions, a greenhouse experiment with rice crop was designed. It was found that composting period and the material type influenced the nutrient and the toxic element content in all windrow composting compositions. Forms of phosphorus present in all windrow composting compositions and quantified by the fractionation mainly corresponded to the fraction of moderately labile. The inoculant addition at windrow composting promoted the solubilization of apatite concentrate and this P was incorporated in the organic fractions of labile P (NaHCO3 in 0.5 mol L-1) and moderately labile P (NaOH 0.1 mol L-1). Moreover, the bacterial inoculant increased P uptake by rice in clay soil, probably due to the formation of P forms with lower tendency of fixation in the soil.

NAPL (non-aqueous phase liquid) blob mobilization and solubilization models were developed to predict residual NAPL fate and describe flow dynamics of various displacing phases (water and surfactant foam). The models were achieved by pore-scale mass and force balances and were focused on the understanding of the physico-chemical interactions between NAPL blobs and the displacing phases. The pore-level mass balance indicated changes in NAPL saturation instead of mass reduction occurring with blob solubilization. The force balance was used to explain the complex flow configurations among NAPL blobs and the displacing phases. Some factors such as the wettability and the spreading/entering coefficients were useful in determining flow configurations. From the models developed in this study, dimensional analysis was performed to identify NAPL blob motion during water or surfactant foam flooding. In non-dimensionalized forms, a Trapping number employed as an indicator of blob displacement performance was modified to quantify the onset of blob mobilization. Its value for water flooding was nearly 2-3 orders of magnitude greater than that of surfactant foam flooding. Next, to investigate the blob flow regime in porous media, a blob velocity was computed. Regardless of the displacing phases, a blob’s velocity increased with increasing blob sizes after commencement of blob motion, and the velocity of DNAPL (dense non-aqueous phase liquid) blobs was greater than that of LNAPL (light non-aqueous phase liquid) blobs. From this investigation, it is expected that the pore-scale solubilization and mobilization models would provide better understanding leading to a predictive capability for the flow behavior of NAPL blobs removed by various displacing phases in a porous medium. Additionally, the models based on newly approached concepts and modified governing equations would be useful in conceptualization, as well as the model prediction of other immiscible or miscible fluids flowing through a porous medium. Further, the models developed in our study would be a useful contribution to the study of small-scale contaminants or substances such as particle and bacterial transport in porous media.

The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD. This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.

Although plant growth-promoting rhizobacteria (PGPR) have shown tremendous potential to be used as inoculants for many agricultural crops, they may not survive severe environmental conditions in the field which could limit their large scale applications. Endophytic bacteria, which can be recovered from inside plant tissues such as roots, stems and leaves, might overcome this limitation due to their unique ecological niche inside plant roots where they are sheltered from external environmental disturbances. Some of these bacterial endophytes have beneficial effects on their host plants and stimulate plant growth or reduce disease symptoms, apparently through mechanisms that are similar to those proposed for PGPR. The objective of this study was to assess a collection of endophytic bacteria for PGPR traits and potential use to enhance the rhizobial-legume symbiosis. Forty isolates obtained from the roots of various plants were identified by fatty acid methyl ester (FAME) analysis, and 16S RNA gene sequencing analysis. The majority (i.e., 75%) were identified as Pseudomonas species. Many of these isolates were able to solubilize phosphate, produce indole-3-acetic acid (IAA), produce aminocyclopropane-1-carboxylic acid (ACC) deaminase, synthesize siderophores and show antagonistic activities against several soil-borne plant pathogenic fungi under in vitro conditions. Selected isolates were further evaluated for the ability to enhance plant growth and nodulation of alfalfa when co-inoculated with Sinorhizobium meliloti under growth chamber conditions using growth pouch and potted soil assays. Results revealed that P. putida strain EB EE 4-25, P. syringae strain EB XDE 4-48, and P. fluorescens strain EB EE 2-23 significantly increased shoot length, root length, enhanced nodulation and increased lateral root formation of alfalfa plants in growth pouch and potted soil assays when co-inoculated with S. meliloti strain P102 compared to plants inoculated with S. meliloti strain P102 alone. Results also suggested that expression of one or more of the mechanisms, such as solubilization of phosphate, production of IAA, production of siderophores, and ACC deaminase production might have played a role in the enhancement of the alfalfa- Sinorhizobium symbiosis. These results suggest that some endophytic bacterial strains may be useful as biofertilizers and/or biocontrol agents in sustainable agricultural practices.