ESPEN practical guideline on clinical nutrition in acute and chronic pancreatitis.

Both acute and chronic pancreatitis are frequent diseases of the pancreas, which, despite being of benign nature, are related to a significant risk of malnutrition and may require nutritional support. Acute necrotizing pancreatitis is encountered in 20 % of patients with acute pancreatitis, is associated with increased morbidity and mortality, and may require artificial nutrition by enteral or parenteral route, as well as additional endoscopic, radiological or surgical interventions. Chronic pancreatitis represents a chronic inflammation of the pancreatic gland with development of fibrosis. Abdominal pain leading to decreased oral intake, as well as exocrine and endocrine failure are frequent complications of the disease. All of the above represent risk factors related to malnutrition. Therefore, patients with chronic pancreatitis should be considered at risk, screened and supplemented accordingly. Moreover, osteoporosis and increased facture risk should be acknowledged in patients with chronic pancreatitis, and preventive measures should be considered.

Utilization of delactosed whey permeate for the synthesis of ethyl acetate with Kluyveromyces marxianus.

Ethyl acetate is an important organic solvent and currently produced from fossil carbon resources. Microbial synthesis of this ester from sugar-rich waste could be an interesting alternative. Therefore, synthesis of ethyl acetate by Kluyveromyces marxinanus DSM 5422 from delactosed whey permeate (DWP) was studied in an aerated stirred bioreactor at 40 °C. DWP is mainly composed of residual lactose and minerals. The minerals inhibited yeast growth, as witnessed by an increased lag period, a reduced growth rate, and an extended process duration. All experiments were therefore carried out with diluted DWP. In a series of batch experiments, the pH of iron-deficient DWP medium varied between 4.8 and 5.9. The pH of the cultivation medium significantly influenced cell growth and product syntheses, with the highest ethyl acetate yield of 0.347 g g-1 and lowest by-product formation achieved at pH 5.1. It is likely that this effect is due to pH-dependent iron chelation, which affects the iron bioavailability and the intracellular iron content, thus affecting growth and metabolite synthesis. The viability of yeast cells was always high despite the harsh conditions in DWP medium, which enabled extended usage of the biomass in repeated-batch and fed-batch cultivations. These two culture techniques increased the volume of DWP processed per time by 32 and 84% for the repeated-batch and the fed-batch cultivation, respectively, without a drop of the ester yield. KEY POINTS: • Delactosed whey permeate was converted to ethyl acetate with a high rate and yield. • The formation of ethyl acetate in DWP medium at iron limitation is pH-dependent. • Highly active yeasts from batch processes enabled extension as fed and repeated batch.

A new approach for balancing the microbial synthesis of ethyl acetate and other volatile metabolites during aerobic bioreactor cultivations.

Ethyl acetate is an organic solvent with many industrial applications, currently produced by energy-intensive chemical processes based on fossil carbon resources. Ethyl acetate can be synthesized from renewable sugars by yeasts like Kluyveromyces marxianus in aerobic processes. However, ethyl acetate is highly volatile and thus stripped from aerated cultivation systems which complicate the quantification of the produced ester. Synthesis of volatile metabolites is commonly monitored by repeated analysis of metabolite concentrations in both the gas and liquid phase. In this study, a model-based method for quantifying the synthesis and degradation of volatile metabolites was developed. This quantification of volatiles is solely based on repeatedly measured gas-phase concentrations and allows calculation of reaction rates and yields in high temporal resolution. Parameters required for these calculations were determined in abiotic stripping tests. The developed method was validated for ethyl acetate, ethanol and acetaldehyde which were synthesized by K. marxianus DSM 5422 during an iron-limited batch cultivation; it was shown that the presented method is more precise and less time-consuming than the conventional method. The biomass-specific synthesis rate and the yield of ethyl acetate varied over time and exhibited distinct momentary maxima of 0.50 g g‒1h‒1 and 0.38 g g‒1 at moderate iron limitation.

Synthesis of ethyl acetate from glucose by Kluyveromyces marxianus, Cyberlindnera jadinii and Wickerhamomyces anomalus depending on the induction mode.

Ethyl acetate is currently produced from fossil carbon resources. This ester could also be microbially synthesized from sugar-rich wastes of the food industry. Wild-type strains with GRAS status are preferred for such applications. Production of ethyl acetate by wild-type yeasts has been repeatedly reported, but comparative studies with several strains at various induction modes are largely missing. Here, synthesis of ethyl acetate by three yeasts with GRAS status, Kluyveromyces marxianus DSM 5422, Cyberlindnera jadinii DSM 2361 and Wickerhamomyces anomalus DSM 6766, was studied under identical and well-defined conditions in an aerated bioreactor, by inducing the ester synthesis via iron or oxygen limitation. Balancing the ester synthesis was based on measured concentrations of ethyl acetate in the exhaust gas, delivering masses of synthesized ester and synthesis rates in a high temporal resolution. All tested yeasts synthesized ethyl acetate under these conditions, but the intensity varied with the strain and induction mode. The highest yields were achieved under iron limitation with K. marxianus (0.182 g g-1) and under oxygen limitation with W. anomalus (0.053 g g-1). Iron limitation proved to be the better inducer for ester synthesis while oxygen limitation favored ethanol formation. K. marxianus DSM 5422 was the most potent producer of ethyl acetate exhibiting the highest biomass-specific synthesis rate of 0.5 g g-1h-1 under moderate iron limitation.

ESPEN guideline on clinical nutrition in acute and chronic pancreatitis.

Both acute and chronic pancreatitis are frequent diseases of the pancreas, which, despite being of benign nature, are related to a significant risk of malnutrition and may require nutritional support. Acute necrotizing pancreatitis is encountered in 20% of patients with acute pancreatitis, is associated with increased morbidity and mortality, and may require artificial nutrition by enteral or parenteral route, as well as additional endoscopic, radiological or surgical interventions. Chronic pancreatitis represents a chronic inflammation of the pancreatic gland with development of fibrosis. Abdominal pain leading to decreased oral intake, as well as exocrine and endocrine failure are frequent complications of the disease. All of the above represent risk factors related to malnutrition. Therefore, patients with chronic pancreatitis should be considered at risk, screened and supplemented accordingly. Moreover, osteoporosis and increased facture risk should be acknowledged in patients with chronic pancreatitis, and preventive measures should be considered.

Modeling population dynamics in a microbial consortium under control of a synthetic pheromone-mediated communication system.

Microbial consortia can be used to catalyze complex biotransformations. Tools to control the behavior of these consortia in a technical environment are currently lacking. In the present study, a synthetic biology approach was used to build a model consortium of two Saccharomyces cerevisiae strains where growth and expression of the fluorescent marker protein EGFP by the receiver strain is controlled by the concentration of α-factor pheromone, which is produced by the emitter strain. We have developed a quantitative experimental and theoretical framework to describe population dynamics in the model consortium. We measured biomass growth and metabolite production in controlled bioreactor experiments, and used flow cytometry to monitor changes of the subpopulations and protein expression under different cultivation conditions. This dataset was used to parameterize a segregated mathematical model, which took into account fundamental growth processes, pheromone-induced growth arrest and EGFP production, as well as pheromone desensitization after extended exposure. The model was able to predict the growth dynamics of single-strain cultures and the consortium quantitatively and provides a basis for using this approach in actual biotransformations.

Alternative Ernährungsformen: Allgemeine Aspekte und vegetarische Kostformen.

Alternative diets (AD) differ from the current common mixed diet; AD are recommended as a permanent diet. These diets are based on ethical, philosophical and health promoting principles and lead to very different recommendations for food selection. Even within a particular AD there is usually a broad spectrum of versions, so that a general evaluation is only possible to a limited extent. This is also true for single AD. Vegetarian diets and partly paleo-diets have been investigated to a reasonable extent. Plant based diets are appropriate as permanent diets and offer health benefits as compared with currently practiced diets (risk reduction of cancers by 10-18% and of heart diseases by 30%; favorable effect on blood pressure and lipid profile; no risk reduction on cancer and total mortality). Vegan diets have to be critically assessed: they are linked to an increased risk of deficits for single nutrients (vitamin B12, iodine and as the case may be. calcium and long chain omega-3 fatty acids), if suitable supplements or fortified foods are not consumed.

Uptake of iron by Kluyveromyces marxianus DSM 5422 cultivated in a whey-based medium.

The ability of Kluyveromyces marxianus for converting lactose into ethyl acetate offers a chance for the economical reuse of whey. Iron plays a significant role in this process as ester synthesis requires a low intracellular iron content, xFe . The iron content in turn is decreased by growth due to cell expansion and increased by iron uptake. Thus, the iron-uptake rate, ψ, is important for the considered process. Iron uptake by K. marxianus DSM 5422 was studied in aerobic cultivation on a whey-borne medium with varied initial iron content, in part combined with a feed of iron under intensive growth conditions. A possible precipitation of iron that would pretend iron uptake was verified not to have occurred. Regularly measured dissolved iron concentrations, CFe,L , allowed the xFe and ψ parameters to be obtained by model-based iron balancing. The achieved data were used for establishing a ψ(CFe,L , xFe ) model. Mathematical simulations based on this iron-uptake model reproduced the performed cultivation processes. The created iron-uptake model allows for a future predictive system to be developed for the optimization of biotechnological ester production.

Studies on the mechanism of synthesis of ethyl acetate in Kluyveromyces marxianus DSM 5422.

Kluyveromyces marxianus converts whey-borne sugar into ethyl acetate, an environmentally friendly solvent with many applications. K. marxianus DSM 5422 presumably synthesizes ethyl acetate from acetyl-SCoA. Iron limitation as a trigger for this synthesis is explained by a diminished aconitase and succinate dehydrogenase activity (both enzymes depend on iron) causing diversion of acetyl-SCoA from the tricarboxic acid cycle to ester synthesis. Copper limitation as another trigger for ester synthesis in this yeast refers to involvement of the electron transport chain (all ETC complexes depend on iron and complex IV requires copper). This hypothesis was checked by using several ETC inhibitors. Malonate was ineffective but carboxin partially inhibited complex II and initiated ester synthesis. Antimycin A and cyanide as complexes III and IV inhibitors initiated ester synthesis only at moderate levels while higher concentrations disrupted all respiration and caused ethanol formation. A restricted supply of oxygen (the terminal electron acceptor) also initiated some ester synthesis but primarily forced ethanol production. A switch from aerobic to anaerobic conditions nearly stopped ester synthesis and induced ethanol formation. Iron-limited ester formation was compared with anaerobic ethanol production; the ester yield was lower than the ethanol yield but a higher market price, a reduced number of process stages, a faster process, and decreased expenses for product recovery by stripping favor biotechnological ester production.

Perspectives for the biotechnological production of ethyl acetate by yeasts.

Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester.

[Causes an clinical sign of malnutrition]. / Ursachen und Klinik der Mangelernährung.

Malnutrition is a highly relevant independent clinical risk factor with scientifically well-proven clinical and economic consequences. The causes of malnutrition are complex and multifactorial. Malnutrition is frequently caused by medical as well as non-medical social factors as social isolation, inability to gain and/or prepare adequate food as well as poverty. Next to loss of body weight ongoing malnutrition resulted in a large variety of specific and predominantly non-specific symptoms. In patients on risk for malnutrition systematic questioning and targeted physical investigation are mandatory to diagnose malnutrition at an early stage and to evaluate the individually underlying causes in order to guarantee a timely adequate nutritional therapy in those patients.

Growth of Kluyveromyces marxianus and formation of ethyl acetate depending on temperature.

Conversion of lactose into ethyl acetate by Kluyveromyces marxianus allows economic reuse of whey-borne sugar. The high volatility of ethyl acetate enables its process-integrated recovery by stripping. This stripping is governed by both the aeration rate and the partition coefficient, K EA,L/G. Cultivation at elevated temperatures should decrease the K EA,L/G value and thus favor stripping. K. marxianus DSM 5422 as a potent producer of ethyl acetate was cultivated aerobically in whey-borne media for studying temperature-dependent growth and ester formation. Shake flask cultivation proved thermal tolerance of this yeast growing from 7 to 47 °C with a maximum rate of 0.75 h(-1) at 40 °C. The biomass yield was 0.41 g/g at moderate temperatures while low and high temperatures caused distinct drops. The observed µ-T and Y X/S-T dependencies were described by mathematical models. Further cultivations were done in an 1-L stirred reactor for exploring the effect of temperature on ester synthesis. Cultivation at 32 °C caused significant ester formation (Y EA/S = 0.197 g/g) while cultivation at 42 °C suppressed ester synthesis (Y EA/S = 0.002 g/g). The high temperature affected metal dissolution from the bioreactor delivering iron for yeast growth and preventing ester synthesis. Cultivation at 32 °C with a switch to 42 °C at the onset of ester synthesis allowed quick and efficient ester production (Y EA/S = 0.289 g/g). The high temperature lowered the K EA,L/G value from 78 to 44 L/L which heightened the gas-phase ester concentration (favoring ester recovery) without increasing the liquid-phase concentration (avoiding product inhibition).

Formation of ethyl acetate from whey by Kluyveromyces marxianus on a pilot scale.

Whey arising in huge amounts during milk processing is a valuable renewable resource in the field of White Biotechnology. Kluyveromyces marxianus is able to convert whey-borne lactose into ethyl acetate, an environmentally friendly solvent. Formation of ethyl acetate as a bulk product is triggered by iron (Fe). K. marxianus DSM 5422 was cultivated aerobically in whey-borne medium originally containing 40 µg/L Fe, supplemented with 1, 3 or 10 mg/L Fe in the pre-culture, using an 1 L or 70 L stirred reactor. The highest Fe content in the pre-culture promoted yeast growth in the main culture causing a high sugar consumption for growth and dissatisfactory formation of ethyl acetate, while the lowest Fe content limited yeast growth and promoted ester synthesis but slowed down the process. An intermediate Fe dose (ca. 0.5 µg Fe/g sugar) lastly represented a compromise between some yeast growth, a quite high yield of ethyl acetate and an acceptable duration of the process. The mass of ethyl acetate related to the sugar consumed amounted to 0.113, 0.265 and 0.239 g/g in the three processes corresponding to 21.9%, 51.4% and 46.3% of the theoretically maximum yield. The performance on a pilot scale was somewhat higher than on lab scale.

Formation of ethyl acetate by Kluyveromyces marxianus on whey during aerobic batch and chemostat cultivation at iron limitation.

The ability of Kluyveromyces marxianus to convert lactose into ethyl acetate offers a chance for an economic reuse of whey. Former experiments with K. marxianus DSM 5422 proved limitation of growth by iron (Fe) or copper as a precondition for significant ester synthesis. Several aerobic batch and chemostat cultivations were done with whey-borne media of a variable Fe content for exploring the effect of Fe on growth, the Fe content of biomass, and metabolite synthesis. At low Fe doses, Fe was the growth-limiting factor, the available Fe was completely absorbed by the yeasts, and the biomass formation linearly depended on the Fe dose governed by a minimum Fe content in the yeasts, x (Fe,min). At batch conditions, x (Fe,min) was 8.8 µg/g, while during chemostat cultivation at D = 0.15 h(-1), it was 23 µg/g. At high Fe doses, sugar was the growth-limiting factor, Fe was more or less absorbed, and the formed biomass became constant. Significant amounts of ethyl acetate were only formed at Fe limitation while high Fe doses suppressed ester formation. Analysis of formed metabolites such as glycerol, pyruvate, acetate, ethanol, ethyl acetate, isocitrate, 2-oxoglutarate, succinate, and malate during chemostat cultivation allowed some interpretation of the Fe-dependent mechanism of ester synthesis; formation of ethyl acetate from acetyl-SCoA and ethanol is obviously initiated by a diminished metabolic flux of acetyl-SCoA into the citrate cycle and by a limited oxidation of NADH in the respiratory chain since Fe is required for the function of aconitase, succinate dehydrogenase, and the electron-transferring proteins.

Formation of ethyl acetate by Kluyveromyces marxianus on whey during aerobic batch cultivation at specific trace element limitation.

Kluyveromyces marxianus is able to transform lactose into ethyl acetate as a bulk product which offers a chance for an economical reuse of whey-borne sugar. Ethyl acetate is highly volatile and allows its process-integrated recovery by stripping from the aerated bioreactor. Extensive formation of ethyl acetate by K. marxianus DSM 5422 required restriction of yeast growth by a lack of trace elements. Several aerobic batch processes were done in a 1-L stirred reactor using whey-borne culture medium supplemented with an individual trace element solution excluding Mn, Mo, Fe, Cu, or Zn for identifying the trace element(s) crucial for the observed ester synthesis. Only a lack of Fe, Cu, or Zn restricted yeast growth while exclusion of Mn and Mo did not exhibit any effect due to a higher amount of the latter in the used whey. Limitation of growth by Fe or Cu caused significant production of ethyl acetate while limitation by Zn resulted in formation of ethanol. A lack of Fe or Cu obviously makes the respiratory chain inefficient resulting in an increased mitochondrial NADH level followed by a reduced metabolic flux of acetyl-SCoA into the citrate cycle. Synthesis of ethyl acetate from acetyl-SCoA and ethanol by alcoholysis is thus interpreted as an overflow metabolism.

Formation of ethyl acetate by Kluyveromyces marxianus on whey: studies of the ester stripping.

Kluyveromyces marxianus is capable of converting lactose into ethyl acetate offering a chance for an economical reuse of whey. The microbial formation of ethyl acetate as a bulk product calls for an aerobic process and, thus, the highly volatile ethyl acetate is discharged from the aerated bioreactor. This stripping process was modeled and investigated experimentally. The stripping rate was proportional to the gas flow and nearly independent of the stirring rate since the stripping was governed by the absorption capacity of the exhaust gas rather than the phase transfer. Cooling the exhaust gas did not noticeably influence the stripping. One batch experiment is presented in detail to demonstrate the formation of ethyl acetate by K. maxianus DSM 5422 on whey. Further batch experiments showed that a substantial formation of ethyl acetate only occurred when the yeast growth was limited by a lack of trace elements. The highest product yield observed was 0.25 g ethyl acetate per g lactose which is nearly 50% of the theoretical maximum.

Malnutrition in hospital: the clinical and economic implications.

BACKGROUND: Undernutrition and malnutrition are common in hospitalized patients. Their combined prevalence on admission is estimated at 25% and is rising. METHODS: Selective literature review with special consideration of current guidelines and meta-analyses. RESULTS: The nutritional state of every patient should be assessed on admission with simple, established parameters, and patients suffering from under- or malnutrition should be treated with a targeted nutritional intervention based on the established stepwise treatment algorithm. Under- and malnutrition are an independent risk and cost factor with a significant influence on mortality, morbidity, length of hospital stay, and quality of life. Their direct costs alone amount to some 9 billion Euros in Germany each year. Therapeutic trials and meta-analyses have clearly documented the therapeutic benefit and cost-effectiveness of oral nutritional supplements and tube feeds. Targeted nutritional intervention is an integral part of medical treatment and prevention. CONCLUSION: Undernutrition and malnutrition are common in hospitalized patients and are both medically and economically harmful. If they are detected early by targeted assessment and then treated appropriately according to the established stepwise treatment algorithm, better clinical outcomes and lower costs will result.

Remediation of heavy metal polluted sediment by suspension and solid-bed leaching: estimate of metal removal efficiency.

Remediation of heavy metal polluted sediment by extracting the metals with sulfuric acid can be performed as follows: abiotic suspension leaching, microbial suspension leaching, abiotic solid-bed leaching, and microbial solid-bed leaching. Abiotic leaching means that the acid is directly added, while microbial leaching means that the acid is generated from sulfur by microbes (bioleaching). These four principles were compared to each other with special emphasis on the effectiveness of metal solubilization and metal removal by subsequent washing. Abiotic suspension leaching was fastest, but suspending the solids exhibits some disadvantages (low solid content, costly reactors, permanent input of energy, high water consumption, special equipment required for solid separation, large amounts of waste water, sediment properties hinder reuse), which prevent suspension leaching in practice. Abiotic solid-bed leaching implies the supply of acid by percolating water which proceeds slowly due to a limited bed permeability. Microbial solid-bed leaching means the generation of acid within the bed and has been proven to be the only principle applicable to practice. Metal removal from leached sediment requires washing with water. Washing of solid beds was much more effective than washing of suspended sediment. The kinetics of metal removal from solid beds 0.3, 0.6 or 1.2m in height were similar; when using a percolation flow of 20lm(-2)h(-1), the removal of 98% of the mobile metals lasted 57-61h and required 8.5, 4.2 or 2.3lkg(-1) water. This means, the higher the solid bed, the lower the sediment-mass-specific demand for time and water.