Anaerobic digestion is a common process for treatment of wastewater sludge from municipal sewage systems. Volatile sulfur compounds, including volatile organic sulfur compounds (VOSCs) and hydrogen sulfide, have been reported as the most odorous compounds in digestion emissions and impurities which can damage facilities for generation, transportation, storage, and utilization of biogas. There has been no comprehensive study on biological generation and degradation kinetics of VOSC or modeling VOSC behaviors through anaerobic sludge digestion. The goal of the present study was to establish a model for VOSC conversions in anaerobic sludge digestion which could facilitate quantitative analysis of VOSC emissions in anaerobic digestion. VOSCs and methionine were employed in dosed batch tests. VOSC conversion processes in anaerobic methionine digestion have been identified. The kinetics for the identified VOSC degradation and conversion processes were determined at 35 and 55 °C respectively. Mixed-second order kinetics were found to best fit the conversion processes. A model was established based on the identified processes and estimated kinetic constants. To extend the model to VOSC release in anaerobic sludge digestion, mesophilic and thermophilic incubations were conducted with four different sludge samples. The effects of temperature and sludge source on VOSC release patterns were assessed. It was found that an unidentified DMS generation mechanism was triggered in the mesophilic incubation of activated sludge in which iron was dosed. To apply the model which was established based on methionine degradation in sludge digestion, hydrolysis of particulate materials was incorporated. The model simulations for VOSC behavior in thermophilic batch incubation were able to represent the observed VOSC releases. However, the simulations could not well fit the observed VOSC release at 35 ° because the model did not include the unidentified DMS generation mechanism. Application of the model to bench-scale digesters was lack-of-fit. It may have been due to imprecise estimation of the degradable sulfur in the feed sludge. In addition, in the batch tests and digester operation the ratios of the raw and digested sludge were different. This might have resulted in different concentrations of the microorganisms which mediated biotransformations and hence resulted in different kinetic constants.

Anaerobic membrane bioreactors may provide a sustainable technological solution for digestion of waste activated sludge due to their capacity to achieve substantial volatile solids (VS) destruction and positive energy balances with reduced digester volumes. However, membrane integrated anaerobic systems may have limitations that are imposed by membrane fouling and a decrease in biomass activity due to possible exposure of biomass to high shear conditions. This study characterised bioprocess and membrane performance under varying conditions, identified foulant type and origin and mechanism of fouling, and developed fouling control strategies by using low cross flow velocity and pressure anaerobic membrane systems. The study employed a pilot scale anaerobic digester integrated with negative and neutral tubular membranes; pilot and bench scale control digesters supported with bench scale filtration unit parametric studies. The membranes were polyvinylidene difluoride based with an average pore size of 0.02 micron and were operated at a constant cross flow velocity of 1 ms-1 and constant trans-membrane pressure of 30 kPa. Four operating conditions consisting of different combinations of HRT and SRT were evaluated. By integrating membranes into the digesters it was possible to simultaneously enhance digestion and increase throughput of the digesters without affecting its performance. The anaerobic membrane digester showed 48-49% volatile solids destruction at 30 days SRT under conventional and higher loadings of 1.2±0.4 and 2.1±0.6 kg COD m-3day-1. This was a 100% increase in performance compared to a control digester subjected to higher loading. This result was supported by the associated specific methane generation. The control digesters operated at a relatively higher SRT showed comparable VS destruction and gas generation to the anaerobic membrane running at a similar SRT. However the extra gas generated didn’t compensate heat required to maintain larger volume of the digester. In case of anaerobic membrane digesters due to the high rate feeding, increase biogas production and co-thickening, the energy balance increased by 144 and 200% under conventional and higher loading conditions respectively. Characterization of membrane performance showed that the average sustainable flux was 23.2±0.4 and 14.8±0.4 LMH during HRT-SRTs of 15-30 and 7-15 days respectively. The critical fluxes were in the range of 30-40, 16-17 and 20-22 LM-2H-1 during HRT-SRTs of 15-30, 7-30 and 7-15 days respectively. The decline in membrane performance at a higher loading was associated with the formation of cake layers on the membrane surface that led to reversible fouling. The additional decline in performance at extended SRT was attributed to irreversible fouling. The colloidal fraction of the sludge showed an overall higher fouling propensity during the long term pilot studies and short term filtration tests. The suspended solids fraction of the sludge showed a positive impact at concentration below 15 g/L but resulted in a decrease of membrane performance at higher concentrations. Further studies of foulant origin through a series of microscopic, membrane cleaning and sludge characterization studies showed that the colloidal proteins, soluble carbohydrates and inorganic materials such as iron, calcium and sulfur and their interaction to have a significant impact on membrane fouling. To control anaerobic membrane fouling by the digested sludge, integration of membrane relaxation techniques in the filtration cycle were found effective. By incorporating a unique relaxation technique to tubular membranes, it was possible to increase the sustainable flux to 29.2±1.8 and 34.5±2.5 LM-2H-1 for neutral and negative membranes during 15-30 HRT-SRT process condition. Addition of cationic polymers and sequential mechanical-citric acid membrane cleaning, that targeted both reversible and irreversible fouling was also found effective.

Undersökningen har genomförts i en förskola och en förskoleklass där totalt tjugo barn har deltagit. Den syftar till att undersöka hur kunskapen skiljer sig mellan fyraåringar och sexåringar. Kvalitativa intervjuer och löpande observationer användes som metod för att ta reda på uppfattningar om människokroppens inre organ samt vad barnen anser händer med maten som vi äter. I undersökningen användes en plastmodell av en kropp som barnen både fick peka på och säga organens namn. Resultatet visar att sexåringar generellt har bättre uppfattning när det gäller organens namn och vad organen gör i vår kropp. Däremot har båda åldersgrupperna en likvärdig uppfattning när det gäller att peka ut organ och benämna det rätt. Sexåringarna var också bättre på vad de anser händer med maten vi äter i jämförelse med fyraåringarna. Det tycks vara åldern hos barnen som påverkar vad barnen kan i störst utsträckning, där personliga erfarenheter tycks spela in vid enstaka tillfällen. / This study was conducted in a kindergarten and a preschool where a total of twenty children have attended. It aims to investigate how knowledge differs between four-year and six-year-old children. Qualitative interviews and current observations were used as methods to find out the perceptions of the human body's internal organs, as well as what the children think happens to the food we eat. The study used a plastic model of a body that the children both got the chance to point at as well as name the organs. The results show that six year olds generally have better perceptions of the organs name and what they are doing in our body. However, both age groups had a similar view when it comes to point out an organ and name it correctly. Six year olds were also better at what they think happens to the food we eat compared to four year olds. It seems to be the age of the children that have the biggest affects on their knowledge, but it can also be their experiences that are the main factor in a few cases.

Bandymas atliktas siekiant ištirti didžiojo prieskrandžio biocheminius ir mikrobiologinius rodiklius, šeriant karves skirtingos sudėties racionais; įvertinti didžiojo prieskrandžio fermentacinį aktyvumą; ištirti žolinių pašarų – šieno, šienainio, kukurūzų siloso virškinamumą in vitro, inkubuojant juos su skirtingo fermentacinio aktyvumo didžiojo prieskrandžio turiniu. Iš gautų rezultatų galime teigti, kad skirtingos sudėties racionai turi įtakos karvių didžiojo prieskrandžio turinio mikrobiologiniams ir biocheminiams rodikliams. Nustatyta, kad I (kontrolinės) grupės karvių didžiojo prieskrandžio turinio ph buvo 10,5 proc. (p<0,0001) mažesnis; redukcinis bakterijų aktyvumas vyko 131 s (p<0,0001) greičiau; gliukozės rūgimo reakcija buvo 71,4 proc. (p<0,0001) didesnė; pirmuonių rasta 120 103/ (p<0,0001) daugiau; LRR gamyba padidėjo 27,2 proc. palyginant su II (bandomosios) grupės karvėmis, kurios buvo šeriamos nesubalansuotu racionu. Subalansuoto raciono įvairesni ir maistingesni pašarai nulėmė, kontrolinės grupės aktyvesnį didžiojo prieskrandžio turinio fermentacinį procesą. Subalansuotame racione vyravo šienainis (55 proc.), kukurūzų silosas (20 proc.) ir kombinuotieji pašarai (20,7 proc.). Racionas buvo praturtintas melasa (0,62 proc.) ir BVMP (0,37 proc.). Bandomosios karvės iš sultingųjų pašarų gavo tik kukurūzų siloso, kuris ir sudarė didžiausią raciono dalį (75 proc.). Jų racione nebuvo šienainio, kuris yra 2-3 kartus maistingesnis palyginti su kukurūzų silosu (2... [toliau žr. visą tekstą] / Aim of thesis: to analyse the dependence of forage organic material digestion on the level of cows’ long prestomach fermentation. Tasks: 1. To estimate biochemical and microbiological factors of large prestomach content of cows, fed by different consist rations and to evaluate fermentational activity; 2. To examine herby forage- hay, haylage and maize silage- organic material digestion in vitro by incubating them with different fermentational activity content of long prestomach. In the course of work the following was identified: 1. Ph of long prestomach content of cows fed by balanced ration was 10,5 % (p<0,0001) lower, the reaction of bacteria reductional activity was 131 s (p<0,0001) faster, the reaction of glucoses fermentation was 71,4 % (p<0,0001) higher, protoza was found 120 103 / ml (p<0,0001) more, the production of free fatty acids increased by 27,2 % (p<0,0001) in comparison with cows, which were fed by unbalanced ration. 1.1. Therefore fermentational processes of long prestomach of cows fed by balanced ration were active, and of those fed by unbalanced ration- slowed down. 2. When incubating hay, haylage and silage in vitro with different fermentational activity content of long prestomach, organic material digestion (OMD) of all examined forage was highest by incubating them with active fermentation long prestomach content: 2.1. organic material digestion (OMD) was of hay 5,52 % (p<0,0001) higher; organic material digestion (OMD) was of haylage 5,5 % (p<0,0001)... [to full text]

Fragaria ananassa, generally known as strawberry is a nutritious fruit that is rich in polyphenols and widely consumed as part of a healthy diet. Anthocyanins have been found to be the main group of phenolic components present in strawberry with pelargonidin-3-glucoside as the major component in all strawberry cultivars studied. The main volatile component has been identified as caryophyllene oxide, a sesquiterpene compound that was present abundantly in all cultivars. The effect of preharvest spray applications of a formulation containing hexanal which is known to enhance membrane preservation, was evaluated using two strawberry cultivars, ‘Jewel’ and ‘Mira’. Our results suggest that preharvest spray application of hexanal formulation results in biochemical changes that alter the profile of phenolic compounds and the volatiles of the fruit. An osmotic infusion treatment was implemented to generate an intermediate moisture food product with high quality and enhanced storage life that can be potentially used in processed food. Infusing strawberry with other functional ingredients such as fructoligosaccharides, lecithin, and ascorbic acid showed that the infused strawberry produced by this technique was structurally and organoleptically similar to fresh strawberry, and visually similar to the intial fruits. Drying of infused fruits could extend their shelf life up to several months, while providing fruit products with superior nutritional qualities. Subjecting strawberry fruit extract to a simulated in vitro digestion of strawberry greatly affected the polyphenol composition and concentrations during different stages of digestion. The concentrations of most polyphenols increased during gastric digestion suggesting that the acidic environment of the stomach may help to release polyphenols that are bound to the strawberry matrix. Following incubation of the IN and the OUT fractions with colonic bacteria, the presence of urolithin B glucunoride in the IN fraction and the increase of ellagic acid deoxyhexoside in both the IN and OUT fractions after fermentation process, suggest that the polyphenols are catabolized into simple phenolic compounds in the colon. The remaining polyphenols as well as the catabolites in the gut, could potentially have a beneficial effect in enhancing colonial health. / Ministry of Higher Education Malaysia, Universiti Putra Malaysia

No description available.

Although carbohydrates are a principal component of the human diet, the mechanism of the final stages of starch digestion is not fully understood. One approach to treating metabolic diseases such as type II diabetes, obesity, and congenital sucrase isomaltase deficiency is inhibition of intestinal α-glucosidases and pancreatic α-amylases. Intestinal α-glucosidases, sucrase isomaltase (SI) and maltase glucoamylase (MGAM), are responsible for the final step of starch hydrolysis in mammals: the release of free glucose. MGAM and SI consist of two catalytic subunits: N-terminal and C-terminal, with overlapping, but variant substrate specificities. The objective of this thesis is to increase the understanding of the differential substrate specificity seen in the catalytic subunits of SI and MGAM. Through inhibitor studies, the structural and biochemical differences between the enzymatic subunits are explored, illustrating that each individual catalytic subunit can be selectively inhibited. In Chapter 3, homology models of ctSI and ctMGAM-N20 are presented, giving insight into the residues hypothesized to impact substrate specificity, enhancing our understanding of the functionality of these enzymatic subunits and overlapping substrate specificity. The structural implications of mutations seen in ntSI in CSID patients and the potential functional and structural implications are discussed in Chapter 4 in addition to the prevalence of SNPs in the SI gene in different populations. The mammalian α-glucosidases are compared to the 3 Å structure of CfXyl31, a Family 31 glycoside hydrolase from Cellulomonas fimi. Comparison to Family 31 glycoside hydrolases of known structure gives rise to possible mutations proposed to mimic ntMGAM α-glucosidase activity. Through inhibitor studies, homology models, examining mutations found in disease states such as congenital sucrase isomaltase deficiency, and investigating a bacterial family 31 glycoside hydrolase from Cellulomonas fimi, the active site characteristics and substrate specificities of SI and MGAM are better understood.

Title: Food waste from grocery stores in Umeå- the potential for taking care of and reducing the amount of food waste. Author: Helene Myhrberg Abstract Food waste from grocery stores is an increasing problem in Sweden, and amounts to roughly 67 000 ton per year. This has consequences both for sustainability in general, but also for achieving the targets stipulated by the EU. Given this, it should be relevant for the society that grocery stores both decrease the amount of food waste but also develop better ways of dealing with food waste. Although there exist methods for this, the practicability of such measures are unknown. In this thesis I assess these issues by conducting interviews with owners and employees at five grocery stores in Umeå, asking them how they think about these questions. In particular, I focus on how to take care of and prepare food waste for anaerobic digestion and how to decrease volumes of food waste. In essence, I find that both the knowledge of, and interest in, these issues vary substantially between grocery stores. Further, for these measures to be feasible, it requires the process to be both economically efficient while not requiring too much time of work. With this in mind, it seems necessary to have a facility that can take care of both packed and unpackaged food waste, making it as cheap and simple as possible for the grocery stores. For reducing volumes of waste, most grocery stores agrees on better planning as the way to go. Key words: food waste, grocery stores, anaerobic digestion, decreasing of food waste.

The biogas plant Kungsängens gård, owned by Uppsala Vatten och Avfall AB, produces biogas and biomanure from organic household waste, food processing waste and slaughterhouse waste. In year 2012, 4.4 million Nm3 of biogas were produced from 25 200 tons of waste. Before digestion all substrate is sanitized by pasteurization at 70°C in order to kill pathogens. Another method, integrated thermophilic sanitation (ITS), is of interest in order to decrease the energy demand. The method implies that the substrate is sanitized during ten hours in the digestion chamber, where the temperature is 52°C. The purpose of this thesis was to compare pasteurization with integrated thermophilic sanitation from an energy point of view. The pasteurization´s impact on biogas production and energy yield was examined through experiments with two laboratory digesters, of which one was fed with pasteurized substrate and the other with non-pasteurized substrate. For the present pasteurization system, electricity and heat demand was surveyed. For the integrated thermophilic sanitation, a process design was developed and dimensioned and the electricity and heat demand was calculated. Thereafter, the energy yield and energy demand for the two sanitation systems were compared. The result showed that pasteurization had no effect on biogas production. The energy yield was on average 4.79 kWh/kg VS from non-pasteurized substrate and 4.74 kWh/kg VS from pasteurized substrate. There was no statistically significant difference between the reactors. The energy audit showed that pasteurization required 0.48 kWh/kg VS, which is 85 % of the total energy consumption at the facility. The digester warming demanded 0.077 kWh/kg VS for RK1 and 0.031 kWh/kg VS for RK2. The electricity consumption was 0.041 kWh/kg VS. The process of ITS was designed with a heat exchange from bio manure to substrate, followed by heating to 52°C by steam addition. The heat requirement was 0.24 kWh/kg VS and the electricity demand was 0.034 kWh/kg VS. The warming of the digesters was the same as in the present pasteurization system. The comparison between the existing pasteurization and the ITS showed that switching systems would save 0.243 kWh/kg VS or 46 % of the present energy consumption. This corresponds to annual savings of 1.22 GWh. A sensitivity analysis showed that the results were sensitive to assumptions regarding the heat exchanger in the case of ITS. 10 % energy losses resulted in smaller savings, 34 % or 0.91 GWh per year. There are increased risks of process disruptions if ITS is combined with an increased organic loading rate. 4.2 % reduction of the total biogas production erases the energy savings which means that it is important that process stability is ensured.

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.