Waste to resource: Converting paper mill wastewater to bioplastic

In this study we investigated the feasibility of producing polyhydroxyalkanoate (PHA) by microbial enrichments on paper mill wastewater. The complete process includes (1) paper mill wastewater acidogenic fermentation in a simple batch process, (2) enrichment of a PHA-producing microbial community in a selector operated in sequencing batch mode with feast-famine regime, (3) Cellular PHA content maximization of the enrichment in an accumulator in fed-batch mode. The selective pressure required to establish a PHA-producing microbial enrichment, as derived from our previous research on synthetic medium, was validated using an agro-industrial waste stream in this study. The microbial enrichment obtained could accumulate maximum up to 77% PHA of cell dry weight within 5 h, which is currently the best result obtained on real agro-industrial waste streams, especially in terms of biomass specific efficiency. Biomass in this enrichment included both Plasticicumulans acidivorans, which was the main PHA producer, and a flanking population, which exhibited limited PHA-producing capacity. The fraction of P. acidivorans in the biomass was largely dependent on the fraction of volatile fatty acids in the total soluble COD in the wastewater after acidification. Based on this observation, one simple equation was proposed for predicting the PHA storage capacity of the enrichment. Moreover, some crucial bottlenecks that may impede the successful scaling-up of the process are discussed.     

Policy integration in the EU governance of global food security

The global food price spikes of 2007–8 and 2010 led to increased awareness of the complexity of food (in)security as a policy problem that crosscuts traditional sectoral, spatial and temporal scales. At the European Union (EU) level, this awareness resulted in calls for better integrated approaches to govern food security. This paper addresses the question of to what extent these calls were followed by an actual shift towards better integrated EU food security governance. We address this question by applying a processual policy integration framework that distinguishes four integration dimensions: (i) the policy frame, (ii) subsystem involvement, (iii) policy goals, and (iv) policy instruments. The empirical body of evidence for assessing shifts in these dimensions draws upon an extensive analysis of EU documents complemented with interview data. We find that policy integration advanced to at least some degree: the policy frame expanded towards new dimensions of food security; a wider array of subsystems started discussing food security concerns; food security goals diversified somewhat and there was an increased awareness of coherence and linkages with other issues; existing instruments, including internal procedural instruments, were expanded and made more consistent; and new types of instruments were developed. At the same time, significant differences exist between policy domains and policy integration efforts seem to have come to a halt in recent years. We conclude with various policy recommendations and suggestions for follow-up research.     

Identification and prediction of distress trajectories in the first year after a breast cancer diagnosis.

Objective: In this article, we aim to (a) identify distinct trajectories of psychological distress in the first year after a breast cancer diagnosis in women treated with adjuvant therapy and (b) explore possible predictors of these trajectories, that is, demographic, medical, and personal characteristics. Method: The 171 patients were assessed after diagnosis, after surgery, after adjuvant treatment, in the reentry phase, and in the (short-term) survivorship phase (2 and 6 months after the end of treatment, respectively). Main Outcome Measure: Psychological distress was assessed with the 12-item General Health Questionnaire. Results: There were four trajectories of distress: a group that experienced no distress (36.3%), a group that experienced distress only in the active treatment phase (33.3%), a group that experienced distress in the reentry and survivorship phase (15.2%), and a group that experienced chronic distress (15.2%). Personality and physical complaints resulting from adjuvant treatment could distinguish the distress trajectories. Mastery was the only unique predictor. Conclusion: Most patients were not distressed in response to breast cancer or only temporarily so. Yet, a minority of patients became or remained distressed after the end of treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of syntrophic microbial communities in high-rate methanogenic bioreactors

Anaerobic purification is a cost-effective way to treat high strength industrial wastewater. Through anaerobic treatment of wastewaters energy is conserved as methane, and less sludge is produced. For high-rate methanogenesis compact syntrophic communities of fatty acid-degrading bacteria and methanogenic archaea are essential. Here, we describe the microbiology of syntrophic communities in methanogenic reactor sludges and provide information on which microbiological factors are essential to obtain high volumetric methane production rates. Fatty-acid degrading bacteria have been isolated from bioreactor sludges, but also from other sources such as freshwater sediments. Despite the important role that fatty acid-degrading bacteria play in high-rate methanogenic bioreactors, their relative numbers are generally low. This finding indicates that the microbial community composition can be further optimized to achieve even higher rates.     

The correctness of Newman’s typability algorithm and some of its extensions

We study Newman’s typability algorithm (Newman, 1943) [14] for simple type theory. The algorithm originates from 1943, but was left unnoticed until (Newman, 1943) [14] was recently rediscovered by Hindley (2008) [10]. The remarkable thing is that it decides typability without computing a type. We give a modern presentation of the algorithm (also a graphical one), prove its correctness and show that it implicitly does compute the principal type. We also show how the typing algorithm can be extended to other type constructors. Finally we show that Newman’s algorithm actually includes a unification algorithm.     

Marital satisfaction in patients with cancer: Does support from intimate partners benefit those who need it most?

This cross-sectional study assessed 3 ways of providing spousal support. Active engagement means involving the patient in discussions and using constructive problem-solving methods; protective buffering means hiding one's concerns; and overprotection refers to underestimation of the patient's capabilities, resulting in unnecessary help and excessive praise for accomplishments. Ratings of received spousal support by 68 patients with cancer revealed findings similar to those of partners' ratings of provided support. The positive association between active engagement and the patient's marital satisfaction was stronger for patients with a rather poor psychological and physical condition than for those with a rather good condition. Furthermore, protective buffering and overprotection were negatively associated with marital satisfaction only when patients experienced relatively high levels of psychological distress or physical limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The synthesis of poly(butylene terephthalate) from terephthalic acid,part II: Assessment of the first stage of the polymerization process

The production of poly(butylene terephthalate) (PBT) struggles with the formation of substantial amounts of tetrahydrofuran (THF). When PBT is synthesized from terephthalic acid (TPA) instead of dimethyl terephthalate (DMT), even more THF is formed, mainly during the first stage of the melt polymerization process. Although a lot of literature reports on the existence of this side reaction in both processes, to the best of our knowledge, a comparison, which reveals the importance of the acidity and insolubility of TPA on the THF formation, was never described. Finally, an interesting study was performed on the THF formation during the synthesis of PBT from mixtures of DMT and TPA as well as from the completely soluble monomethyl terephthalate (MMT). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Metabolic modeling of mixed substrate uptake for polyhydroxyalkanoate (PHA) production

Polyhydroxyalkanoate (PHA) production by mixed microbial communities can be established in a two-stage process, consisting of a microbial enrichment step and a PHA accumulation step. In this study, a mathematical model was constructed for evaluating the influence of the carbon substrate composition on both steps of the PHA production process. Experiments were conducted with acetate, propionate, and acetate propionate mixtures. Microbial community analysis demonstrated that despite the changes in substrate composition the dominant microorganism was Plasticicumulans acidivorans in all experiments. A metabolic network model was established to investigate the processes observed. The model based analysis indicated that adaptation of the acetate and propionate uptake rate as a function of acetate and propionate concentrations in the substrate during cultivation occurred. The monomer composition of the PHA produced was found to be directly related to the composition of the substrate. Propionate induced mainly polyhydroxyvalerate (PHV) production whereas only polyhydroxybutyrate (PHB) was produced on acetate. Accumulation experiments with acetate-propionate mixtures yielded PHB/PHV mixtures in ratios directly related to the acetate and propionate uptake rate. The model developed can be used as a useful tool to predict the PHA composition as a function of the substrate composition for acetate-propionate mixtures.     

Reduced iron induced nitric oxide and nitrous oxide emission

Formation of the greenhouse gas nitrous oxide in water treatment systems is predominantly studied as a biological phenomenon. There are indications that also chemical processes contribute to these emissions. Here we studied the formation of nitric oxide (NO) and nitrous oxide (N₂O) due to chemical nitrite reduction by ferrous iron (Fe(II)). Reduction of nitrite and NO coupled to Fe(II) oxidation was studied in laboratory-scale chemical experiments at different pH, nitrite and iron concentrations. The continuous measurement of both NO and N₂O emission showed that nitrite reduction and NO reduction have different kinetics. Nitrite reduction shows a linear dependency on the nitrite concentration, implying first order kinetics in nitrite. The nitrite reduction seems to be an equilibrium based reaction, leading to a constant NO concentration in the liquid. The NO reduction rate is suggested to be most dependent on reactive surface availability and the sorption of Fe(II) to the reactive surface. The importance of emission of NO and N₂O coupled to iron oxidation is exemplified by iron reduction experiments and several examples of environments where this pathway can play a role.