Genome-scale metabolic modeling to provide insight into the production of storage compounds during feast–famine cycles of activated sludge

2013 ◽  
Vol 67 (3) ◽  
pp. 469-476 ◽  
Author(s):  
Mohammad Tajparast ◽  
Dominic Frigon
Keyword(s):  
Activated Sludge ◽  
Carbon Sources ◽  
Value Added ◽  
Growth Cycle ◽  
Glycogen Accumulation ◽  
Storage Compounds ◽  
Metabolic Models ◽  
K 12 ◽  
Genome Scale ◽  
By Products

Studying storage metabolism during feast–famine cycles of activated sludge treatment systems provides profound insight in terms of both operational issues (e.g., foaming and bulking) and process optimization for the production of value added by-products (e.g., bioplastics). We examined the storage metabolism (including poly-β-hydroxybutyrate [PHB], glycogen, and triacylglycerols [TAGs]) during feast–famine cycles using two genome-scale metabolic models: Rhodococcus jostii RHA1 (iMT1174) and Escherichia coli K-12 (iAF1260) for growth on glucose, acetate, and succinate. The goal was to develop the proper objective function (OF) for the prediction of the main storage compound produced in activated sludge for given feast–famine cycle conditions. For the flux balance analysis, combinations of three OFs were tested. For all of them, the main OF was to maximize growth rates. Two additional sub-OFs were used: (1) minimization of biochemical fluxes, and (2) minimization of metabolic adjustments (MoMA) between the feast and famine periods. All (sub-)OFs predicted identical substrate–storage associations for the feast–famine growth of the above-mentioned metabolic models on a given substrate when glucose and acetate were set as sole carbon sources (i.e., glucose–glycogen and acetate–PHB), in agreement with experimental observations. However, in the case of succinate as substrate, the predictions depended on the network structure of the metabolic models such that the E. coli model predicted glycogen accumulation and the R. jostii model predicted PHB accumulation. While the accumulation of both PHB and glycogen was observed experimentally, PHB showed higher dynamics during an activated sludge feast–famine growth cycle with succinate as substrate. These results suggest that new modeling insights between metabolic predictions and population ecology will be necessary to properly predict metabolisms likely to emerge within the niches of activated sludge communities. Nonetheless, we believe that the development of this approach will help guide the optimization of the production of storage compounds as valuable by-products of wastewater treatment.

scholarly journals Organic Wastes as Feedstocks for Non-Conventional Yeast-Based Bioprocesses

2019 ◽  
Vol 7 (8) ◽  
pp. 229 ◽  
Author(s):  
Diem T. Hoang Do ◽  
Chrispian W. Theron ◽  
Patrick Fickers
Keyword(s):  
Carbon Sources ◽  
Value Added ◽  
Building Blocks ◽  
Organic Wastes ◽  
Cell Factory ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Alternative Feedstocks ◽  
Global Population ◽  
By Products

Non-conventional yeasts are efficient cell factories for the synthesis of value-added compounds such as recombinant proteins, intracellular metabolites, and/or metabolic by-products. Most bioprocess, however, are still designed to use pure, ideal sugars, especially glucose. In the quest for the development of more sustainable processes amid concerns over the future availability of resources for the ever-growing global population, the utilization of organic wastes or industrial by-products as feedstocks to support cell growth is a crucial approach. Indeed, vast amounts of industrial and commercial waste simultaneously represent an environmental burden and an important reservoir for recyclable or reusable material. These alternative feedstocks can provide microbial cell factories with the required metabolic building blocks and energy to synthesize value-added compounds, further representing a potential means of reduction of process costs as well. This review highlights recent strategies in this regard, encompassing knowledge on catabolic pathways and metabolic engineering solutions developed to endow cells with the required metabolic capabilities, and the connection of these to the synthesis of value-added compounds. This review focuses primarily, but not exclusively, on Yarrowia lipolytica as a yeast cell factory, owing to its broad range of naturally metabolizable carbon sources, together with its popularity as a non-conventional yeast.

Pyridine Degradation by Suspensions and Biofilms of Achromobacter pulmonis PNOS and Burkholderia dolosa BOS Strains Isolated from Activated Sludge of Sewage Treatment Plants

2020 ◽  
Vol 36 (2) ◽  
pp. 86-98
Author(s):  
A.A. Sergeeva ◽  
G.V. Ovechkina ◽  
A.Yu. Maksimov
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Local Treatment ◽  
Carbon Sources ◽  
Mining Institute ◽  
Bacterial Strains ◽  
Federal Research ◽  
Registration Number ◽  
Treatment Facilities ◽  
Pyridine Degradation

Bacterial strains capable of degradation of 0.8-15.8 g/1 pyridine hydrochloride have been isolated from activated sludge of municipal biological treatment plants in Perm (BOS) and local treatment facilities of the LUKOIL-Permnefteorgsintez enterprise (PNOS). The strains were identified as Achromobacter pulmonis and Burkholderia dolosa. The optimal pyridine concentration for the growth of the isolated strains was 4.0 g/1. The pyridine degradation during the A. pulmonis PNOS and B. dolosa BOS cultivation on a medium with ammonium chloride and glucose and without additional nitrogen or carbon sources was studied. It was shown that the strains are able to accumulate biomass in a medium with pyridine as the sole carbon and nitrogen source; the addition of glucose to the medium (1 g/L) accelerated the pyridine degradation by A. pulmonis PNOS, but inhibited the process carried out by B. dolosa BOS. B. dolosa BOS and A. pulmonis PNOS biofilms efficiently utilized pyridine during growth on basalt and carbon fibers; the highest rate of pyridine utilization (1.8 g /(L day)) was observed in A. pulmonis PNOS biofilms on basalt fibers. pyridine, biodegradation, activated sludge, biofilms, Achromobacter pulmonis, Burkholderia dolosa The authors grateful to Dr. I.I. Tchaikovsky, Head of the Laboratory of Geology of Mineral Deposits of the Mining Institute, a branch of the Perm Federal Research Center, for help with electron microscopy of the samples. This work was carried out as part of a state assignment on the topic « Study of the Functional and Species Diversity of Microorganisms Useful for Ecocenoses and Human Practical Activity», registration number R&D AAAA-A19-119112290008-4.

scholarly journals Valorization of food industry waste and by-products using 3D printing: A study on the development of value-added functional cookies

Future Foods ◽  
2021 ◽  
pp. 100036
Author(s):  
Bhagya Jagadiswaran ◽  
Vishvaa Alagarasan ◽  
Priyadharshini Palanivelu ◽  
Radhika Theagarajan ◽  
J.A. Moses ◽  
...  
Keyword(s):  
3D Printing ◽  
Food Industry ◽  
Value Added ◽  
Industry Waste ◽  
Food Industry Waste ◽  
By Products

Recent advances to recover value-added compounds from avocado by-products following a biorefinery approach

2021 ◽  
Vol 28 ◽  
pp. 100433
Author(s):  
Alexandra Del Castillo-Llamosas ◽  
Pablo G. del Río ◽  
Alba Pérez-Pérez ◽  
Remedios Yáñez ◽  
Gil Garrote ◽  
...  
Keyword(s):  
Value Added ◽  
Recent Advances ◽  
By Products

scholarly journals Recovery of Anthocyanins and Monosaccharides from Grape Marc Extract by Nanofiltration Membranes

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2003
Author(s):  
Paul Muñoz ◽  
Karla Pérez ◽  
Alfredo Cassano ◽  
René Ruby-Figueroa
Keyword(s):  
Functional Foods ◽  
General Trend ◽  
Value Added ◽  
Operating Conditions ◽  
Permeate Flux ◽  
Ultrasound Assisted Extraction ◽  
Grape Marc ◽  
Assisted Extraction ◽  
The One ◽  
By Products

Wastewaters and by-products generated in the winemaking process are important and inexpensive sources of value-added compounds that can be potentially reused for the development of new products of commercial interest (i.e., functional foods). This research was undertaken in order to evaluate the potential of nanofiltration (NF) membranes in the recovery of anthocyanins and monosaccharides from a clarified Carménère grape marc obtained through a combination of ultrasound-assisted extraction and microfiltration. Three different flat-sheet nanofiltration (NF) membranes, covering the range of molecular weight cut-off (MWCO) from 150 to 800 Da, were evaluated for their productivity as well as for their rejection towards anthocyanins (malvidin-3-O-glucoside, malvidin 3-(acetyl)-glucoside, and malvidin 3-(coumaroyl)-glucoside) and sugars (glucose and fructose) in selected operating conditions. The selected membranes showed differences in their performance in terms of permeate flux and rejection of target compounds. The NFX membrane, with the lowest MWCO (150–300 Da), showed a lower flux decay in comparison to the other investigated membranes. All the membranes showed rejection higher than 99.42% for the quantified anthocyanins. Regarding sugars rejection, the NFX membrane showed the highest rejection for glucose and fructose (100 and 92.60%, respectively), whereas the NFW membrane (MWCO 300–500 Da) was the one with the lowest rejection for these compounds (80.57 and 71.62%, respectively). As a general trend, the tested membranes did not show a preferential rejection of anthocyanins over sugars. Therefore, all tested membranes were suitable for concentration purposes.

scholarly journals Brewing By-Product Upcycling Potential: Nutritionally Valuable Compounds and Antioxidant Activity Evaluation

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 165
Author(s):  
Elisabetta Bravi ◽  
Giovanni De Francesco ◽  
Valeria Sileoni ◽  
Giuseppe Perretti ◽  
Fernanda Galgano ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Acids ◽  
Liquid Waste ◽  
Value Added ◽  
Total Phenolic ◽  
Antioxidant Compounds ◽  
Brewing Industry ◽  
Antioxidant Power ◽  
Spent Grains ◽  
By Products

The brewing industry produces high quantities of solid and liquid waste, causing disposal issues. Brewing spent grains (BSGs) and brewing spent hop (BSH) are important by-products of the brewing industry and possess a high-value chemical composition. In this study, BSG and BSH, obtained from the production process of two different types of ale beer (Imperial red and Belgian strong beer) were characterized in terms of valuable components, including proteins, carbohydrates, fat, dietary fiber, β-glucans, arabinoxylans, polyphenols, and phenolic acids, and antioxidant activity (Ferric Reducing Antioxidant Power Assay (FRAP), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)). Significant concentrations of total polyphenols were observed in both BSH and BSG samples (average of about 10 mg GAE/g of dry mass); however, about 1.5-fold higher levels were detected in by-products of Belgian strong ale beer compared with Imperial red. Free and bound phenolic acids were quantified using a validated chromatographic method. A much higher level of total phenolic acids (TPA) (about 16-fold higher) was found in BSG samples compared with BSHs. Finally, their antioxidant potential was verified. By-products of Belgian strong ale beer, both BSG and BSH, showed significantly higher antioxidative capacity (about 1.5-fold lower inhibitory concentration (IC50) values) compared with spent grains and hop from the brewing of Imperial red ale. In summary, BSG and BSH may be considered rich sources of protein, carbohydrates, fiber, and antioxidant compounds (polyphenols), and have the potential to be upcycled by transformation into value-added products.

A Rational and Manageable Value-Added Model for Teacher Preparation Programs

2016 ◽  
Vol 32 (5) ◽  
pp. 728-750 ◽  
Author(s):  
Michael P. Brady ◽  
Katie Miller ◽  
Jazarae McCormick ◽  
Lawrence A. Heiser
Keyword(s):  
Teacher Preparation ◽  
Student Teaching ◽  
Teacher Candidates ◽  
Value Added ◽  
Teacher Preparation Programs ◽  
Full Time ◽  
Preparation Programs ◽  
Grade Point ◽  
Value Added Model ◽  
K 12

Educators struggle with “value-added” teacher evaluation models based on high-stakes student assessments. Despite validity and reliability threats, these models evaluate university-based teacher preparation programs (TPPs), and play a role in state and professional accreditation. This study reports a more rational value-added evaluation model linking student performance to teacher candidates’ lessons during Practicum and Student Teaching. Results indicate that K-12 students showed learning gains on these lessons, with mixed findings on comparisons of part-time to full-time internships, academic and functional lessons, and candidates’ grade point averages (GPAs). Results indicated that teacher candidates’ lessons are a viable value-added model (VAM) alternative for TPPs.

Lipid storage compounds in raw activated sludge microorganisms for biofuels and oleochemicals production

RSC Advances ◽  
2012 ◽  
Vol 2 (5) ◽  
pp. 2015 ◽  
Author(s):  
Emmanuel D. Revellame ◽  
Rafael Hernandez ◽  
William French ◽  
William E. Holmes ◽  
Tracy J. Benson ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Lipid Storage ◽  
Storage Compounds

scholarly journals A Genome-Scale Model of Shewanella piezotolerans Simulates Mechanisms of Metabolic Diversity and Energy Conservation

mSystems ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Keith Dufault-Thompson ◽  
Huahua Jian ◽  
Ruixue Cheng ◽  
Jiefu Li ◽  
Fengping Wang ◽  
...  
Keyword(s):  
Energy Conservation ◽  
Deep Sea ◽  
Carbon Sources ◽  
Scale Model ◽  
Anaerobic Conditions ◽  
A Genome ◽  
Group 2 ◽  
Genome Scale ◽  
Genome Scale Model ◽  
Group 1

ABSTRACT The well-studied nature of the metabolic diversity of Shewanella bacteria makes species from this genus a promising platform for investigating the evolution of carbon metabolism and energy conservation. The Shewanella phylogeny is diverged into two major branches, referred to as group 1 and group 2. While the genotype-phenotype connections of group 2 species have been extensively studied with metabolic modeling, a genome-scale model has been missing for the group 1 species. The metabolic reconstruction of Shewanella piezotolerans strain WP3 represented the first model for Shewanella group 1 and the first model among piezotolerant and psychrotolerant deep-sea bacteria. The model brought insights into the mechanisms of energy conservation in WP3 under anaerobic conditions and highlighted its metabolic flexibility in using diverse carbon sources. Overall, the model opens up new opportunities for investigating energy conservation and metabolic adaptation, and it provides a prototype for systems-level modeling of other deep-sea microorganisms. Shewanella piezotolerans strain WP3 belongs to the group 1 branch of the Shewanella genus and is a piezotolerant and psychrotolerant species isolated from the deep sea. In this study, a genome-scale model was constructed for WP3 using a combination of genome annotation, ortholog mapping, and physiological verification. The metabolic reconstruction contained 806 genes, 653 metabolites, and 922 reactions, including central metabolic functions that represented nonhomologous replacements between the group 1 and group 2 Shewanella species. Metabolic simulations with the WP3 model demonstrated consistency with existing knowledge about the physiology of the organism. A comparison of model simulations with experimental measurements verified the predicted growth profiles under increasing concentrations of carbon sources. The WP3 model was applied to study mechanisms of anaerobic respiration through investigating energy conservation, redox balancing, and the generation of proton motive force. Despite being an obligate respiratory organism, WP3 was predicted to use substrate-level phosphorylation as the primary source of energy conservation under anaerobic conditions, a trait previously identified in other Shewanella species. Further investigation of the ATP synthase activity revealed a positive correlation between the availability of reducing equivalents in the cell and the directionality of the ATP synthase reaction flux. Comparison of the WP3 model with an existing model of a group 2 species, Shewanella oneidensis MR-1, revealed that the WP3 model demonstrated greater flexibility in ATP production under the anaerobic conditions. Such flexibility could be advantageous to WP3 for its adaptation to fluctuating availability of organic carbon sources in the deep sea. IMPORTANCE The well-studied nature of the metabolic diversity of Shewanella bacteria makes species from this genus a promising platform for investigating the evolution of carbon metabolism and energy conservation. The Shewanella phylogeny is diverged into two major branches, referred to as group 1 and group 2. While the genotype-phenotype connections of group 2 species have been extensively studied with metabolic modeling, a genome-scale model has been missing for the group 1 species. The metabolic reconstruction of Shewanella piezotolerans strain WP3 represented the first model for Shewanella group 1 and the first model among piezotolerant and psychrotolerant deep-sea bacteria. The model brought insights into the mechanisms of energy conservation in WP3 under anaerobic conditions and highlighted its metabolic flexibility in using diverse carbon sources. Overall, the model opens up new opportunities for investigating energy conservation and metabolic adaptation, and it provides a prototype for systems-level modeling of other deep-sea microorganisms.

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