Multi-Objective Optimization of Microalgae Metabolism: An Evolutive Algorithm Based on FBA.

Studies enabled by metabolic models of different species of microalgae have become significant since they allow us to understand changes in their metabolism and physiological stages. The most used method to study cell metabolism is FBA, which commonly focuses on optimizing a single objective function. However, recent studies have brought attention to the exploration of simultaneous optimization of multiple objectives. Such strategies have found application in optimizing biomass and several other bioproducts of interest; they usually use approaches such as multi-level models or enumerations schemes. This work proposes an alternative in silico multiobjective model based on an evolutionary algorithm that offers a broader approximation of the Pareto frontier, allowing a better angle for decision making in metabolic engineering. The proposed strategy is validated on a reduced metabolic network of the microalgae Chlamydomonas reinhardtii while optimizing for the production of protein, carbohydrates, and CO2 uptake. The results from the conducted experimental design show a favorable difference in the number of solutions achieved compared to a classic tool solving FBA.

Synthesis of glycerol carbonate from glycerin with CaCO3 in a batch reactor.

In the present work, a reaction methodology was implemented using a batch reactor, which synthesized glycerol carbonate (GC) using glycerin and CaCO3. A crystallographic analysis of CaCO3 was performed to determine its crystalline form. The obtained product was characterized by infrared spectroscopy, thermogravimetric analysis and nuclear magnetic resonance (1H and 13C). Our analysis demonstrated that the obtained product with the implemented reaction methodology has GC, FTIR showed the signals of the carbonyl groups, and the NMR spectrum confirmed the presence of cyclic carbonate structure in addition to linear carbonates. The thermogravimetric study showed that the thermal stability of the product is highly similar to that reported for GC. These results exhibit that the synthesis process produces linear and cyclic carbonates.

Influence of Eu(3+) doping content on antioxidant properties of Lu2O3 sol-gel derived nanoparticles.

This paper presents the synthesis of pure and europium-doped lutetium oxide (Lu2O3) powders prepared by sol-gel method. The influence of europium ion concentration into Lu2O3 nanocrystallites was investigated for first time in an in vitro system using a modified ABTS radical cation decolorization assay to determine the antioxidant activity. The crystalline structure of Lu2O3 and Eu:Lu2O3 powders was elucidated by XRD obtaining cubic phase in all system without secondary products in accordance with FT-IR results. By TEM and Scherrer equation, it was determined that Lu2O3 and Eu:Lu2O3 powders presented nearly spherical particle morphology with crystallites sizes in the range of 8 to 13nm. The antioxidant assays results revealed that europium ion enhance Lu2O3 powders antioxidant properties, showing that 12.5mol% of europium is sufficient to reach its maximum capacity.

Cyclic AMP mediates the cell cycle dynamics of energy metabolism in Saccharomyces cerevisiae.

We have investigated the role of 3',5'-cyclic-adenosine-monophosphate (cAMP) in mediating the coupling between energy metabolism and cell cycle progression in both synchronous cultures and oscillating continuous cultures of Saccharomyces cerevisiae. For the first time, a peak in intracellular cAMP was shown to precede the observed breakdown of trehalose and glycogen during cell cycle-related oscillations. Measurements in synchronous cultures demonstrated that this peak can be associated with the cell cycle dynamics of cAMP under conditions of glucose-limited growth, which was found to differ significantly from that observed in synchronous glucose-repressed cultures. Our results support the notion that cAMP plays a major role in mediating the integration of energy metabolism and cell cycle progression, both in the single cell and during cell cycle-related oscillations in continuous culture, respectively. Evidence is presented that the dynamic behaviour of intracellular cAMP during the cell cycle is modulated depending on nutrient supply. The implications of these findings regarding the role of cAMP in regulating cell cycle progression and energy metabolism are discussed.