Bio-valorization of crude glycerol through polyhydroxyalkanoates production

Due to the prospective partial replacement of fossil fuels by biodiesel, its production has continuously grown in the last decade. The increase in global biodiesel production demands the development of sustainable applications of its main by-product, crude glycerol. In this thesis the feasibility of producing polyhydroxyalkanoates (PHA) by a mixed microbial community using crude glycerol as feedstock was investigated. Several incubation conditions were studied in order to maximize PHA production. The microbial population selected under aerobic dynamic feeding conditions had the ability to consume both major carbon fractions present in the crude, glycerol and methanol. Two biopolymers were stored, poly-3-hydroxybutyrate (PHB) and glucose biopolymer (GB), apparently using glycerol as the only carbon source for their production. The microbial enrichment obtained was able to accumulate up to 47% PHB of cell dry weight with a productivity of 0.24 g HA/L d. The overall PHA yield on total substrate consumed (0.32 g COD HB/g COD crude glycerol) was in the middle range of those reported in literature (0.08–0.58 g COD PHA/g COD real waste). The increase of temperature from 23ºC to 30ºC favored the culture fraction that accumulates glucose biopolymer with a maximum accumulation value of 25% of cell dry weight, which is an interesting value but not the main goal of this thesis. The fact that crude glycerol can be used to produce PHA without any pre-treatment step, makes the overall production process economically more competitive, reducing polymer final cost. This was the first study that demonstrates the valorization of the glycerol fraction present in the crude glycerol into PHA using an aerobic mixed microbial consortium.

Modeling and optimization of extracellular polysaccharides production by Enterobacter A47

Polysaccharides are gaining increasing attention as potential environmental friendly and sustainable building blocks in many fields of the (bio)chemical industry. The microbial production of polysaccharides is envisioned as a promising path, since higher biomass growth rates are possible and therefore higher productivities may be achieved compared to vegetable or animal polysaccharides sources. This Ph.D. thesis focuses on the modeling and optimization of a particular microbial polysaccharide, namely the production of extracellular polysaccharides (EPS) by the bacterial strain Enterobacter A47. Enterobacter A47 was found to be a metabolically versatile organism in terms of its adaptability to complex media, notably capable of achieving high growth rates in media containing glycerol byproduct from the biodiesel industry. However, the industrial implementation of this production process is still hampered due to a largely unoptimized process. Kinetic rates from the bioreactor operation are heavily dependent on operational parameters such as temperature, pH, stirring and aeration rate. The increase of culture broth viscosity is a common feature of this culture and has a major impact on the overall performance. This fact complicates the mathematical modeling of the process, limiting the possibility to understand, control and optimize productivity. In order to tackle this difficulty, data-driven mathematical methodologies such as Artificial Neural Networks can be employed to incorporate additional process data to complement the known mathematical description of the fermentation kinetics. In this Ph.D. thesis, we have adopted such an hybrid modeling framework that enabled the incorporation of temperature, pH and viscosity effects on the fermentation kinetics in order to improve the dynamical modeling and optimization of the process. A model-based optimization method was implemented that enabled to design bioreactor optimal control strategies in the sense of EPS productivity maximization. It is also critical to understand EPS synthesis at the level of the bacterial metabolism, since the production of EPS is a tightly regulated process. Methods of pathway analysis provide a means to unravel the fundamental pathways and their controls in bioprocesses. In the present Ph.D. thesis, a novel methodology called Principal Elementary Mode Analysis (PEMA) was developed and implemented that enabled to identify which cellular fluxes are activated under different conditions of temperature and pH. It is shown that differences in these two parameters affect the chemical composition of EPS, hence they are critical for the regulation of the product synthesis. In future studies, the knowledge provided by PEMA could foster the development of metabolically meaningful control strategies that target the EPS sugar content and oder product quality parameters.

Polyhydroxyalkanoates production by photosynthetic mixed cultures

Polyhydroxyalkanoates (PHAs) are natural biologically synthesized polymers that have been the subject of much interest in the last decades due to their biodegradability. Thus far, its microbial production is associated with high operational costs, which increases PHA prices and limits its marketability. To address this situation, this thesis’ work proposes the utilization of photosynthetic mixed cultures (PMC) as a new PHA production system that may lead to a reduction in operational costs. In fact, the operational strategies developed in this work led to the selection of PHA accumulating PMCs that, unlike the traditional mixed microbial cultures, do not require aeration, thus permitting savings in this significant operational cost. In particular, the first PHA accumulating PMC tested in this work was selected under non-aerated illuminated conditions in a feast and famine regime, being obtained a consortium of bacteria and algae, where photosynthetic bacteria accumulated PHA during the feast phase and consumed it for growth during the famine phase, using the oxygen produced by algae. In this symbiotic system, a maximum PHA content of 20% cell dry weight (cdw) was reached, proving for the first time, the capacity of a PMC to accumulate PHA. During adaptation to dark/light alternating conditions, the culture decreased its algae content but maintained its viability, achieving a PHA content of 30% cdw. Also, the PMC was found to be able to utilize different volatile fatty acids for PHA production, accumulating up to 20% cdw of a PHA co-polymer composed of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (HV) monomers. Finally, a new selective approach for the enrichment of PMCs in PHA accumulating bacteria was tested. Instead of imposing a feast and famine regime, a permanent feast regime was used, thus selecting a PMC that was capable of simultaneously growing and accumulating PHA, being attained a maximum PHA content of 60% cdw, the highest value reported for a PMC thus far. The results presented in this thesis prospect the utilization of cheap, VFA-rich fermented wastes as substrates for PHA production, which combined with this new photosynthetic technology opens up the possibility for direct sunlight illumination, leading to a more cost-effective and environmentally sustainable PHA production process.

Optimizing the Testing Process in Module Testing – Functional Testing Interface

Today's business environment has become increasingly unexpected and fast changing because of the global competition. This new environment requires the companies to organize their control differently, e.g. by logistic process thinking. Logistic process thinking in software engineering applies the principles of production process to immaterial products. Processes must be optimized, so that every phase adds value to the customer, and the lead times can be cut shorter to meet the new customer requirements. The purpose of this thesis is to examine and optimize the testing processes of software engineering concentrating on module testing, functional testing and their interface. The concept of logistic process thinking is introduced through production process, value added model and process management. Also theory of testing based on literature is presented, concentrating on module testing and functional testing. The testing processes of the Case Company are presented together with the project models in which they are implemented. The real life practices in module testing and functional testing and their interface are examined through interviews. These practices are analyzed against the processes and the testing theory, through which ideas for optimizing the testing process are introduced. The project world of the Case Company is also introduced together with two example testing projects in different life cycle phases. The examples give a view of how much effort of the project is put in different types of testing.

Development of Special Pumps Repair Process

Tässä diplomityössä käsitellään erikoispumppujen korjausprosessia teollisuuspumppujen korjauksiin erikoistuneessa konepajassa. Työn pääasiallinen tarkoitus on tuotantoprosessin kehittäminen ja tuotantovaiheiden esitteleminen. Tavoitteen taustalla on pyrkimys entisestään parantaa palvelukykyä ja asiakastyytyväisyyttä.Kolme eri keinoa päätavoitteen saavuttamiseksi ovat tuotannon suunnittelun ja ohjauksen kehittäminen, työssä käsiteltyjen pumpputyyppien korjausprosessien läpäisyaikojen lyhentäminen sekä korjausvaiheiden määrittely ja esittely vaihe vaiheelta. Työssä käsiteltyjä erikoispumpputyyppejä ovat imupumput, monijaksopumput sekä pysty/potkuripumput.Tuotannonsuunnittelun ja -ohjauksen kehittämiseksi sekä läpäisyaikojen lyhentämiseksi työssä etsittiin vaihtoehtoisia toimintatapoja. Kolmas tavoite, eli korjausvaiheiden määrittely, toteutettiin esittelemällä korjausprosessin vaiheet käsitellyillä pumpputyypeillä.Tuloksena saatiin keinoja tuotannon suunnittelun ja hallinnan kehittämiseksi. Useimmat keinot koskevat toimintatapojen selkiyttämistä. Myös keinoja läpäisyaikojen lyhentämiseksi löydettiin. Tietyllä imupumpputyypillä ja -koolla läpäisyajan lyheneminen oli 25 % ja osalla monijaksopumpuista jopa 75 %. Tulokset saavutetaan varastoimalla tiettyjä komponentteja, joilla on pitkä valmistus- tai korjausaika. Pysty/potkuripumppujen korjauksen läpäisyaikaa ei saatu lyhennettyä työn rajausten puitteissa Näiden tulosten lisäksi korjausprosessin toimintatavat määriteltiin.

Design and production of protein nanostructures for biomolecular detection

Particulate nanostructures are increasingly used for analytical purposes. Such particles are often generated by chemical synthesis from non-renewable raw materials. Generation of uniform nanoscale particles is challenging and particle surfaces must be modified to make the particles biocompatible and water-soluble. Usually nanoparticles are functionalized with binding molecules (e.g., antibodies or their fragments) and a label substance (if needed). Overall, producing nanoparticles for use in bioaffinity assays is a multistep process requiring several manufacturing and purification steps. This study describes a biological method of generating functionalized protein-based nanoparticles with specific binding activity on the particle surface and label activity inside the particles. Traditional chemical bioconjugation of the particle and specific binding molecules is replaced with genetic fusion of the binding molecule gene and particle backbone gene. The entity of the particle shell and binding moieties are synthesized from generic raw materials by bacteria, and fermentation is combined with a simple purification method based on inclusion bodies. The label activity is introduced during the purification. The process results in particles that are ready-to-use as reagents in bioaffinity. Apoferritin was used as particle body and the system was demonstrated using three different binding moieties: a small protein, a peptide and a single chain Fv antibody fragment that represents a complex protein including disulfide bridge.If needed, Eu3+ was used as label substance. The results showed that production system resulted in pure protein preparations, and the particles were of homogeneous size when visualized with transmission electron microscopy. Passively introduced label was stably associated with the particles, and binding molecules genetically fused to the particle specifically bound target molecules. Functionality of the particles in bioaffinity assays were successfully demonstrated with two types of assays; as labels and in particle-enhanced agglutination assay. This biological production procedure features many advantages that make the process especially suited for applications that have frequent and recurring requirements for homogeneous functional particles. The production process of ready, functional and watersoluble particles follows principles of “green chemistry”, is upscalable, fast and cost-effective.

Economics of combined power plant and pyrolysis bio-oil production

There are reasons of necessity in bio-fuel use and bio-energy fast development. It includes the material about bio-energy technologies, applications and methods. There are basic thermodynamics and economic theories. The economic calculation presents the comparison between two combinations. There are boiler plant below 20 MW in combination with ablative pyrolysis plant for bio-oil production and CHP plant below 100 MW in combination with the RTP pyrolysis bio-oil production technology. It provides a material about wood chips and bio-oil characteristics and explains it nature, presents the situation around the bio-fuel market or bio-fuel trade. There is a description of pyrolysis technologies such as ablative and RTP. The liquid product of the pyrolysis processes is bio-oil. The bio-oil could be different even of the same production process, because of the raw material nature and characteristics. The calculation shows advantages and weaknesses of combinations and obtained a proof of suppositions. The next thing, proven by this work is the fact that to get more efficiency from energy project it is good possibility to built plants in combinations.

Energetic efficiency of a deep bed swine production system

The aim of this work was to evaluate the energy flows of a commercial production system of swine deep bed in its finishing phase, located in Juiz de Fora, in the State of Minas Gerais, Brazil. Thus, an energy efficiency study was carried out by monitoring a lot of animals, during a 94-day period. The energy rate of each compound involved in the production process was quantified and the matrixes of energy consumption were determined in the form of animal feeding, electrical energy, piglets, material used as deep bed, human labor, equipment, swine buildings, production of alive swine for slaughter, organic fertilizer production (swine deep bed or swine deep litter). From the direct input energy, 80.57% correspond to animal feeding, 11.90% to pigs for slaughter and 6.76% to piglets, while from the energy output 53.45% correspond to the terminating swine and 46.55% to organic fertilizer (swine deep bed). By the results obtained, we can conclude that such production system has corresponded to an industrial and highly specialized agro ecosystem, importing a great part of the energy consumed in the production process, with 41% of energy efficiency.

Light emitting diode (LED) use in artificial lighting for broiler chicken production

Light emitting diode (LED) has been used in commercial poultry industry by presenting superior energy savings and providing feasibility on production process. The objective of this research was to evaluate performance and carcass yield of broiler chickens exposed to different LED colors compared with fluorescent lamps. For that, two experiments (E1 and E2) were performed and 2,646 Cobb® chickens were used. In experiment E1, male birds were exposed to 20 lux artificial lighting with red, yellow, blue, and white LED bulbs; and fluorescent bulb. In experiment E2, male and female birds were exposed to 15 lux artificial lighting with red and blue LED bulbs; and fluorescent bulb. Cumulative weight gain (kg), feed intake (kg), feed conversion, hot carcass weight (kg), carcass yield (%), and breast and thigh + drumstick yield (%) were used as response variables. Results showed no difference (p > 0.05) among treatments for performance, carcass yield, and cut yield in experiment E1. In experiment E2 there was only difference between genders (p < 0.05) and males showed higher total weight gain, feed intake, hot carcass weight and thigh + drumstick yield. Different LED color use had same effect as fluorescent lights on broiler performance and carcass yield.

Assessing environmental impacts using a comparative LCA of industrial and artisanal production processes: "Minas Cheese" case

This study uses the Life Cycle Assessment (LCA) methodology to evaluate and compare the environmental impacts caused by both the artisanal and the industrial manufacturing processes of "Minas cheese". This is a traditional cheese produced in the state of Minas Gerais (Brazil), and it is considered a "cultural patrimony" in the country. The high participation of artisanal producers in the market justifies this research, and this analysis can help the identification of opportunities to improve the environmental performance of several stages of the production system. The environmental impacts caused were also assessed and compared. The functional unit adopted was 1 kilogram (Kg) of cheese. The system boundaries considered were the production process, conservation of product (before sale), and transport to consumer market. The milk production process was considered similar in both cases, and therefore it was not included in the assessment. The data were collected through interviews with the producers, observation, and a literature review; they were ordered and processed using the SimaPro 7 LCA software. According to the impact categories analyzed, the artisanal production exerted lower environmental impacts. This can be justified mainly because the industrial process includes the pasteurization stage, which uses dry wood as an energy source and refrigeration.

Food production in solidarity economy: an issue that goes beyond laws

Abstract Food production within the context of solidarity economy is an alternative way to offer employment and income for a significant part of the Brazilian population. The purpose of this study was to carry out a business diagnosis in order to evaluate the facilities, the production process and hygiene practices of seven solidarity economy enterprises located in the city of Novo Hamburgo, Southern Brazil, that work with food production and sales. Visits took place at the enterprises and a check-list was used to record data. Although food production happens in places with space and setting restrictions, it guarantees distinctive foods with aggregate value, where handlers follow the whole process, from raw materials selection to sales. Basic hygiene principles are followed, as they guarantee the production of food with quality, which contributes towards income generation for participating families. Specific laws that apply to the characteristics and needs of small-scale food production must be written in order to regulate solidarity economy enterprises.

Improvements in Fermentative Hydrogen Production through Physiological Manipulation and Metabolic Engineering

La production biologique d'hydrogène (H2) représente une technologie possible pour la production à grande échelle durable de H2 nécessaire pour l'économie future de l'hydrogène. Cependant, l'obstacle majeur à l'élaboration d'un processus pratique a été la faiblesse des rendements qui sont obtenus, généralement autour de 25%, bien en sous des rendements pouvant être atteints pour la production de biocarburants à partir d'autres processus. L'objectif de cette thèse était de tenter d'améliorer la production d'H2 par la manipulation physiologique et le génie métabolique. Une hypothèse qui a été étudiée était que la production d'H2 pourrait être améliorée et rendue plus économique en utilisant un procédé de fermentation microaérobie sombre car cela pourrait fournir la puissance supplémentaire nécessaire pour une conversion plus complète du substrat et donc une production plus grande d'H2 sans l'aide de l'énergie lumineuse. Les concentrations optimales d’O2 pour la production de H2 microaérobie ont été examinées ainsi que l'impact des sources de carbone et d'azote sur le processus. La recherche présentée ici a démontré la capacité de Rhodobacter capsulatus JP91 hup- (un mutant déficient d’absorption-hydrogénase) de produire de l'H2 sous condition microaérobie sombre avec une limitation dans des quantités d’O2 et d'azote fixé. D'autres travaux devraient être entrepris pour augmenter les rendements d'H2 en utilisant cette technologie. De plus, un processus de photofermentation a été créé pour améliorer le rendement d’H2 à partir du glucose à l'aide de R. capsulatus JP91 hup- soit en mode non renouvelé (batch) et / ou en conditions de culture en continu. Certains défis techniques ont été surmontés en mettant en place des conditions adéquates de fonctionnement pour un rendement accru d'H2. Un rendement maximal de 3,3 mols de H2/ mol de glucose a été trouvé pour les cultures en batch tandis que pour les cultures en continu, il était de 10,3 mols H2/ mol de glucose, beaucoup plus élevé que celui rapporté antérieurement et proche de la valeur maximale théorique de 12 mols H2/ mol de glucose. Dans les cultures en batch l'efficacité maximale de conversion d’énergie lumineuse était de 0,7% alors qu'elle était de 1,34% dans les cultures en continu avec un rendement de conversion maximum de la valeur de chauffage du glucose de 91,14%. Diverses autres approches pour l'augmentation des rendements des processus de photofermentation sont proposées. Les résultats globaux indiquent qu'un processus photofermentatif efficace de production d'H2 à partir du glucose en une seule étape avec des cultures en continu dans des photobioréacteurs pourrait être développé ce qui serait un processus beaucoup plus prometteur que les processus en deux étapes ou avec les co-cultures étudiés antérieurément. En outre, l'expression hétérologue d’hydrogenase a été utilisée comme une stratégie d'ingénierie métabolique afin d'améliorer la production d'H2 par fermentation. La capacité d'exprimer une hydrogénase d'une espèce avec des gènes de maturation d'une autre espèce a été examinée. Une stratégie a démontré que la protéine HydA orpheline de R. rubrum est fonctionnelle et active lorsque co-exprimée chez Escherichia coli avec HydE, HydF et HydG provenant d'organisme différent. La co-expression des gènes [FeFe]-hydrogénase structurels et de maturation dans des micro-organismes qui n'ont pas une [FeFe]-hydrogénase indigène peut entraîner le succès dans l'assemblage et la biosynthèse d'hydrogénase active. Toutefois, d'autres facteurs peuvent être nécessaires pour obtenir des rendements considérablement augmentés en protéines ainsi que l'activité spécifique des hydrogénases recombinantes. Une autre stratégie a consisté à surexprimer une [FeFe]-hydrogénase très active dans une souche hôte de E. coli. L'expression d'une hydrogénase qui peut interagir directement avec le NADPH est souhaitable car cela, plutôt que de la ferrédoxine réduite, est naturellement produit par le métabolisme. Toutefois, la maturation de ce type d'hydrogénase chez E. coli n'a pas été rapportée auparavant. L'opéron hnd (hndA, B, C, D) de Desulfovibrio fructosovorans code pour une [FeFe]-hydrogénase NADP-dépendante, a été exprimé dans différentes souches d’E. coli avec les gènes de maturation hydE, hydF et hydG de Clostridium acetobutylicum. L'activité de l'hydrogénase a été détectée in vitro, donc une NADP-dépendante [FeFe]-hydrogénase multimérique active a été exprimée avec succès chez E. coli pour la première fois. Les recherches futures pourraient conduire à l'expression de cette enzyme chez les souches de E. coli qui produisent plus de NADPH, ouvrant la voie à une augmentation des rendements d'hydrogène via la voie des pentoses phosphates.

Modelling the uptake and growth kinetics of Penicillium glabrum in a tannic acid-containing solid-state fermentation for tannase production

A mathematical growth model for the batch solid-state fermentation process for fungal tannase production was developed and tested experimentally. The unstructured model describes the uptake and growth kinetics of Penicillium glabrum in an impregnated polyurethane foam substrate system. In general, good agreement between the experimental data and model simulations was obtained. Biomass, tannase and spore production are described by logistic kinetics with a time delay between biomass production and tannase and spore formation. Possible induction mechanisms for the latter are proposed. Hydrolysis of tannic acid, the main carbon source in the substrate system, is reasonably well described with Michaelis-Menten kinetics with time-varying enzyme concentration but a more complex reaction mechanism is suspected. The metabolism of gallic acid, a tannase-hydrolysis product of tannic acid, was shown to be growth limiting during the main growth phase. (c) 2004 Elsevier Ltd. All rights reserved.

Application of logistic regression for fault analysis in an industrial printing process

A statistical technique for fault analysis in industrial printing is reported. The method specifically deals with binary data, for which the results of the production process fall into two categories, rejected or accepted. The method is referred to as logistic regression, and is capable of predicting future fault occurrences by the analysis of current measurements from machine parts sensors. Individual analysis of each type of fault can determine which parts of the plant have a significant influence on the occurrence of such faults; it is also possible to infer which measurable process parameters have no significant influence on the generation of these faults. Information derived from the analysis can be helpful in the operator's interpretation of the current state of the plant. Appropriate actions may then be taken to prevent potential faults from occurring. The algorithm is being implemented as part of an applied self-learning expert system.

(Non-)ergodicity of a degenerate diffusion modeling the fiber lay down process

We analyze the large time behavior of a stochastic model for the lay down of fibers on a moving conveyor belt in the production process of nonwovens. It is shown that under weak conditions this degenerate diffusion process has a unique invariant distribution and is even geometrically ergodic. This generalizes results from previous works [M. Grothaus and A. Klar, SIAM J. Math. Anal., 40 (2008), pp. 968–983; J. Dolbeault et al., arXiv:1201.2156] concerning the case of a stationary conveyor belt, in which the situation of a moving conveyor belt has been left open.