Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process

International audienceIn order to identify an optimal aeration strategy for intensifying bio-fuel ethanol production in fermentation processes where growth and production have to be managed simultaneously, we quantified the effect of aeration conditions—oxygen limited vs non limited culture (micro-aerobic vs aerobic culture)—on the dynamic behaviour of Saccharomyces cerevisiae cultivated in very high ethanol performance fed-batch cultures. Fermentation parameters and kinetics were established within a range of ethanol concentrations (up to 147 g l−1), which very few studies have addressed. Higher ethanol titres (147 vs 131 g l−1 in 45 h) and average productivity (3.3 vs 2.6 g l−1 h−1) were obtained in cultures without oxygen limitation. Compared to micro-aerobic culture, full aeration led to a 23% increase in the viable cell mass as a result of the concomitant increase in growth rate and yield, with lower ethanol inhibition. The second beneficial effect of aeration was better management of by-product production, with production of glycerol, the main by-product, being strongly reduced from 12 to 4 g l−1. We demonstrate that aeration strategy is as much a determining factor as vitamin feeding (Alfenore et al. 2002) in very high ethanol performance (147 g l−1 in 45 h) in order to achieve a highly competitive dynamic process

Multi-objective particle swarm optimization (MOPSO) of lipid accumulation in Fed-batch cultures

Dynamic optimization of fermentation processes could demand the use of multiple criteria to attain certain objectives, which in most cases are conflicting to each other. The use of Pareto optimal sets supplies the necessary information to take decisions about the trade-offs between objectives. In this work, a multi-objective optimization algorithm based on particle swarm optimization (MOPSO) is used to optimize lipid contents in fermentations with Yarrowia lipolytica. A reduced model was developed to shorten the computation time of MOPSO. A pattern search algorithm was sequentially coupled to MOPSO to execute a dynamic optimization handling physical constraints. Three cases are analyzed to emphasize the response of our control strategy. Simulation results showed that MOPSO - pattern search algorithm achieved high lipid fraction and productivity

Cardioprotection following injury heart failure afforded by a non-enzymatic oxygenated metabolite of omega 3 fatty acid involves ryanodine receptor mechanism and Mitochondrial Function

Organized by Euro Fed Lipi

Early calcium handling imbalance in pressure overload-induced heart failure with nearly normal left ventricular ejection fraction

International audienceHeart failure with preserved ejection fraction (HFpEF) is a common clinical syndrome associated with high morbidity and mortality. Therapeutic options are limited due to a lack of knowledge of the pathology and its evolution. We investigated the cellular phenotype and Ca2+ handling in hearts recapitulating HFpEF criteria. HFpEF was induced in a portion of male Wistar rats four weeks after abdominal aortic banding. These animals had nearly normal ejection fraction and presented elevated blood pressure, lung congestion, concentric hypertrophy, increased LV mass, wall stiffness, impaired active relaxation and passive filling of the left ventricle, enlarged left atrium, and cardiomyocyte hypertrophy. Left ventricular cell contraction was stronger and the Ca2+ transient larger. Ca2+ cycling was modified with a RyR2 mediated Ca2+ leak from the sarcoplasmic reticulum and impaired Ca2+ extrusion through the Sodium/Calcium exchanger (NCX), which promoted an increase in diastolic Ca2+. The Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA2a) and NCX protein levels were unchanged. The phospholamban (PLN) to SERCA2a ratio was augmented in favor of an inhibitory effect on the SERCA2a activity. Conversely, PLN phosphorylation at the calmodulin-dependent kinase II (CaMKII)-specific site (PLN-Thr17), which promotes SERCA2A activity, was increased as well, suggesting an adaptive compensation of Ca2+ cycling. Altogether our findings show that cardiac remodeling in hearts with a HFpEF status differs from that known for heart failure with reduced ejection fraction. These data also underscore the interdependence between systolic and diastolic "adaptations" of Ca2+ cycling with complex compensative interactions between Ca2+ handling partner and regulatory proteins

“The ambition in my love” : The theater of courtly conduct in All’s Well that Ends Well

This chapter explores the gendered nature and language of courtly conduct in Shakespeare’s All’s Well that Ends Well, a work concerned with the ambiguity of gendered courtly conduct, in words, objects, and deeds, which can be interpreted as a critical commentary on contemporary French court life and its leading, female protagonists. Verbal play, material culture, and actions are shown to be key to an articulation and practice of emotions that underpins the successful operation of the court. In this context, coupling may be less a meeting of hearts than a joining of well-matched individuals, each able to perform a range of courtly behaviors successfully by learning to dissimulate through words, attire, and deeds to achieve their goals