58 research outputs found
A preference based measure of complementary feeding quality: Application to the Avon Longitudinal Study of Parents and Children
This paper presents the development of the Complementary Feeding Utility Index (CFUI), a composite index aimed to measure adherence to infant feeding guidelines. Through an axiomatic characterization this paper shows the advantages in using the CFUI are the following: it avoids the use of arbitrary cut-offs, and by converting observed diet preferences into utilities, summing the score is meaningful. In addition, as the CFUI is designed to be scored continuously, it allows the transition from intake of beneficial foods (in low quantities) and intake of detrimental foods (in high quantities) to be more subtle. The paper first describes the rationale being the development of the CFUI and then elaborates on the methodology used to develop the CFUI, including the process of selecting the components. The methodology is applied to data collected from the Avon Longitudinal Study of Parents and Children to show the advantages of the CFUI over traditional diet index approaches. Unlike traditional approaches, the distribution of the CFUI does not peak towards mean value but distributes evenly towards the tails of the distribution.Murthy N. Mittinty, Rebecca K. Golley, Lisa G. Smithers, Laima Brazionis, John W. Lync
Fermentation of deproteinized cheese whey powder solutions to ethanol by engineered Saccharomyces cerevisiae : effect of supplementation with corn steep liquor and repeated-batch operation with biomass recycling by flocculation
The lactose in cheese whey is an interesting
substrate for the production of bulk commodities such as
bio-ethanol, due to the large amounts of whey surplus
generated globally. In this work, we studied the performance
of a recombinant Saccharomyces cerevisiae strain
expressing the lactose permease and intracellular Ăź-galactosidase
from Kluyveromyces lactis in fermentations of
deproteinized concentrated cheese whey powder solutions.
Supplementation with 10 g/l of corn steep liquor significantly
enhanced whey fermentation, resulting in the production
of 7.4% (v/v) ethanol from 150 g/l initial lactose in
shake-flask fermentations, with a corresponding productivity
of 1.2 g/l/h. The flocculation capacity of the yeast
strain enabled stable operation of a repeated-batch process
in a 5.5-l air-lift bioreactor, with simple biomass recycling
by sedimentation of the yeast flocs. During five consecutive
batches, the average ethanol productivity was 0.65 g/l/h
and ethanol accumulated up to 8% (v/v) with lactose-toethanol
conversion yields over 80% of theoretical. Yeast
viability (>97%) and plasmid retention (>84%) remained
high throughout the operation, demonstrating the stability
and robustness of the strain. In addition, the easy and
inexpensive recycle of the yeast biomass for repeated utilization
makes this process economically attractive for
industrial implementation.Fundação para a Ciência e a Tecnologia (FCT)LACTOGAL-Produtos Alimentares S.A.Companhia Portuguesa de Amidos, S.A
Improving the iMM904 S. cerevisiae metabolic model using essentiality and synthetic lethality data
<p>Abstract</p> <p>Background</p> <p><it>Saccharomyces cerevisiae </it>is the first eukaryotic organism for which a multi-compartment genome-scale metabolic model was constructed. Since then a sequence of improved metabolic reconstructions for yeast has been introduced. These metabolic models have been extensively used to elucidate the organizational principles of yeast metabolism and drive yeast strain engineering strategies for targeted overproductions. They have also served as a starting point and a benchmark for the reconstruction of genome-scale metabolic models for other eukaryotic organisms. In spite of the successive improvements in the details of the described metabolic processes, even the recent yeast model (i.e., <it>i</it>MM904) remains significantly less predictive than the latest <it>E. coli </it>model (i.e., <it>i</it>AF1260). This is manifested by its significantly lower specificity in predicting the outcome of grow/no grow experiments in comparison to the <it>E. coli </it>model.</p> <p>Results</p> <p>In this paper we make use of the automated GrowMatch procedure for restoring consistency with single gene deletion experiments in yeast and extend the procedure to make use of synthetic lethality data using the genome-scale model <it>i</it>MM904 as a basis. We identified and vetted using literature sources 120 distinct model modifications including various regulatory constraints for minimal and YP media. The incorporation of the suggested modifications led to a substantial increase in the fraction of correctly predicted lethal knockouts (i.e., specificity) from 38.84% (87 out of 224) to 53.57% (120 out of 224) for the minimal medium and from 24.73% (45 out of 182) to 40.11% (73 out of 182) for the YP medium. Synthetic lethality predictions improved from 12.03% (16 out of 133) to 23.31% (31 out of 133) for the minimal medium and from 6.96% (8 out of 115) to 13.04% (15 out of 115) for the YP medium.</p> <p>Conclusions</p> <p>Overall, this study provides a roadmap for the computationally driven correction of multi-compartment genome-scale metabolic models and demonstrates the value of synthetic lethals as curation agents.</p
Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods
With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage
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