Design and implementation of sensor systems for control of a closed-loop life support system

The sensing and controlling needs for a Closed-Loop Life Support System (CLLSS) were investigated. The sensing needs were identified in five particular areas and the requirements were defined for workable sensors. The specific areas of interest were atmosphere and temperature, nutrient delivery, plant health, plant propagation and support, and solids processing. The investigation of atmosphere and temperature control focused on the temperature distribution within the growth chamber as well as the possibility for sensing other parameters such as gas concentration, pressure, and humidity. The sensing needs were studied for monitoring the solution level in a porous membrane material along with the requirements for measuring the mass flow rate in the delivery system. The causes and symptoms of plant disease were examined and the various techniques for sensing these health indicators were explored. The study of sensing needs for plant propagation and support focused on monitoring seed viability and measuring seed moisture content as well as defining the requirements for drying and storing the seeds. The areas of harvesting, food processing, and resource recycling, were covered with a main focus on the sensing possibilities for regulating the recycling process

Dissecting a complex chemical stress: chemogenomic profiling of plant hydrolysates.

The efficient production of biofuels from cellulosic feedstocks will require the efficient fermentation of the sugars in hydrolyzed plant material. Unfortunately, plant hydrolysates also contain many compounds that inhibit microbial growth and fermentation. We used DNA-barcoded mutant libraries to identify genes that are important for hydrolysate tolerance in both Zymomonas mobilis (44 genes) and Saccharomyces cerevisiae (99 genes). Overexpression of a Z. mobilis tolerance gene of unknown function (ZMO1875) improved its specific ethanol productivity 2.4-fold in the presence of miscanthus hydrolysate. However, a mixture of 37 hydrolysate-derived inhibitors was not sufficient to explain the fitness profile of plant hydrolysate. To deconstruct the fitness profile of hydrolysate, we profiled the 37 inhibitors against a library of Z. mobilis mutants and we modeled fitness in hydrolysate as a mixture of fitness in its components. By examining outliers in this model, we identified methylglyoxal as a previously unknown component of hydrolysate. Our work provides a general strategy to dissect how microbes respond to a complex chemical stress and should enable further engineering of hydrolysate tolerance

Lactic fermentation as a strategy to improve the nutritional and functional values of pseudocereals

One of the greatest challenges is to reduce malnutrition worldwide while promoting sustainable agricultural and food systems. This is a daunting task due to the constant growth of the population and the increasing demands by consumers for functional foods with higher nutritional values. Cereal grains are the most important dietary energy source globally; wheat, rice, and maize currently provide about half of the dietary energy source of humankind. In addition, the increase of celiac patients worldwide has motivated the development of gluten-free foods using alternative flour types to wheat such as rice, corn, cassava, soybean, and pseudocereals (amaranth, quinoa, and buckwheat). Amaranth and quinoa have been cultivated since ancient times and were two of the major crops of the Pre-Colombian cultures in Latin-America. In recent years and due to their well-known high nutritional value and potential health benefits, these pseudocereals have received much attention as ideal candidates for gluten-free products. The importance of exploiting these grains for the elaboration of healthy and nutritious foods has forced food producers to develop novel adequate strategies for their processing. Fermentation is one of the most antique and economical methods of producing and preserving foods and can be easily employed for cereal processing. The nutritional and functional quality of pseudocereals can be improved by fermentation using Lactic Acid Bacteria (LAB). This review provides an overview on pseudocereal fermentation by LAB emphasizing the capacity of these bacteria to decrease antinutritional factors such as phytic acid, increase the functional value of phytochemicals such as phenolic compounds, and produce nutritional ingredients such as B-group vitamins. The numerous beneficial effects of lactic fermentation of pseudocereals can be exploited to design novel and healthier foods or grain ingredients destined to general population and especially to patients with coeliac disease.Fil: Rollan, Graciela Celestina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Gerez, Carla Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Effects of blanching on color, texture and sodium chloride content during storage time of frozen vegetable soybean modeling for commercial scale

Vegetable soybeans [Glycine max (L.) Merrill] are a green stage of soybeans, which have become increasingly popular among health-conscious Americans as an alternative low-fat and heart-healthy food. Vegetable soybeans (VSB) are also an excellent source of protein and fiber. However, the vast majority of the VSB consumed are imported, as they are not extensively grown and processed in the United States. The situation results in short supply and limited processing information. The purpose of this study was to investigate the effects of water blanching (at 86, 92, 98 °C for 1m30s, 2m, 2m30s) and steam blanching (at 86, 92, 98 °C for 1m30s, 2m, 2m30s, 2m50s) on color, texture and sodium chloride content of frozen VSB during six-month storage time. It was hypothesized in this study that decreasing in blanching time and temperature from the conventional commercial process (98 °C for 2m30s – water blanching and 98 °C for 2m50s – steam blanching) would not affect the quality attributes of frozen VSB. The results showed that blanching at temperatures lower than 98 °C for both methods did not completely inactive the peroxidase in VSB, which may cause quality losses during storage. Water blanching at shorter time than the control (2m30s) in commercial processing experiment did not effectively tenderize the texture of VSB. On the other hand, blanching time of all experiments can be reduced to 1m30s with comparable quality to the conventional processes. Blanching apparently affected quality of VSB while freezing and frozen storage had no significant effects on the final product. Optimal processing results in the improvement of production efficiency, increasing production yield and profits. Knowledge from this study is anticipated to be, more or less, supportive and informative for VSB producers in the United States and everyone who interested in this valuable commodity, vegetable soybeans. Advisors: Milford A. Hanna, Curtis L. Welle

APPLICATION OF THIN FILM ANALYSIS TECHNIQUES AND CONTROLLED REACTION ENVIRONMENTS TO MODEL AND ENHANCE BIOMASS UTILIZATION BY CELLULOLYTIC BACTERIA

Cellulose from energy crops or agriculture residues can be utilized as a sustainable energy resource to produce biofuels such as ethanol. The process of converting cellulose into solvents and biofuels requires the saccharification of cellulose into soluble, fermentable sugars. However, challenges to cellulosic biofuel production include increasing the activity of cellulose-degrading enzymes (cellulases) and increasing solvent (ethanol) yield while minimizing the co-production of organic acids. This work applies novel surface analysis techniques and fermentation reactor perturbations to quantify, manipulate, and model enzymatic and metabolic processes critical to the efficient production of cellulosic biofuels. Surface analysis techniques utilizing cellulose thin film as the model substrate are developed to quantify the kinetics of cellulose degradation by cellulase as well as the interactions with cellulase at the interfacial level. Quartz Crystal Microbalance with Dissipation (QCM-D) is utilized to monitor the change in mass of model cellulose thin films cast. The time-dependent frequency response of the QCM simultaneously measures both enzyme adsorption and hydrolysis of the cellulose thin film by fungal cellulases, in which a significant reduction in the extent of hydrolysis can be observed with increasing cellobiose concentrations. A mechanistic enzyme reaction scheme is successfully applied to the QCM frequency response for the first time, describing adsorption/desorption and hydrolysis events of the enzyme, inhibitor, and enzyme/inhibitor complexes. The effect of fungal cellulase concentration on hydrolysis is tested using the QCM frequency response of cellulose thin films. Atomic Force Microscopy (AFM) is also applied for the first time to the whole cell cellulases of the bacterium C. thermocellum, where the effect of temperature on hydrolysis activity is quantified. Fermentation of soluble sugars to desirable products requires the optimization of product yield and selectivity of the cellulolytic bacterium, Clostridium thermocellum. Metabolic tools to map the phenotype toward desirable solvent production are developed through environmental perturbation. A significant change in product selectivity toward ethanol production is achieved with exogenous hydrogen and the addition of hydrogenase inhibitors (e.g. methyl viologen). These results demonstrate compensatory product formation in which the shift in metabolic activity can be achieved through environmental perturbation without permanent change in the organism’s genome

Development and validation of chromatographic methods to study folate derivatives produced by yeasts

Folate, or folic acid, is an important water soluble B vitamin that exists in many different forms. Its presence is necessary for synthesis of DNA and RNA and methylation of homocysteine to methionine. Deficiency of folate is closely connected to increased risk of neural tube defects, a serious birth defect, and development of anaemia. Humans cannot synthesise folate by themselves and therefore depend on an adequate supply through food intake. However, the recommended daily intake of folate is not reached by many people, especially women in fertile ages. This thesis aimed to investigate possibilities for enhancing folate production from yeast for use as biofortificants in food to increase the natural folate content. To quantify folate, analytical methods were developed and validated. This involved optimisation of sample pre-treatment steps, HPLC methods and LC-MS methods. The main findings were that folate analysis of yeast could be facilitated by excluding an SPE step prior to HPLC analysis, that sample handling and choice of antioxidant greatly influenced folate stability, that choice of reversed-phase column considerably affected folate separation/retention and that LC-MS provided a powerful tool for yeast folate analysis. These developed analytical methods were used to investigate differences between yeast strains to produce folates. Furthermore, effect of cultivation conditions on folate content in yeast was studied. The main conclusions from these experiments were that careful selection of yeast strain may considerably increase folate content in food. It was also shown that folate concentration in yeast was significantly increased by optimising the cultivation procedure. The folate derivatives that were found to exist in yeast were tetrahydrofolate, 5-methyltetrahydrofolate, 10-formylfolic acid and 5-formyltetrahydrofolate. The findings in this thesis show that there are great possibilities for increasing folate content in yeast-fermented foods, e.g. bread and dairy products, if a proper yeast strain is used under optimal growth conditions in appropriate culturing media

Biotechnological production of taxanes: a molecular approach

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/46988Plant cell cultures constitute a promise for the production of a high number of phytochemicals, although the majority of bioprocesses that have been developed so far have not resulted commercially successful. An overview indicates that most of the research carried out until now is of the empirical type. For this reason, there is a need for a rational approach to the molecular and cellular basis of metabolic pathways and their regulation in order to stimulate future advances. The empirical investigations are based on the optimization of the culture system, exclusively considering input factors such as the selection of cellular lines, type and parameters of culture, bioreactor design and elicitor addition, and output factors such as cellular growth, the uptake system of nutrients, production and yield. In a rational approach towards the elucidation of taxol and related taxane production, our group has studied the relationship between the taxane profile and production and the expression of genes codifying for enzymes that participate in early, intermediate and late steps of their biosynthesis in elicited Taxus spp cell cultures. Our results show that elicitors induce a dramatic reprogramming of gene expression in Taxus cell cultures, which likely accounts for the enhanced production of taxol and related taxanes and we have also determined some genes that control the main flux limiting steps. The application of metabolic engineering techniques for the production of taxol and taxanes of interest is also discussed