Search for effective oral adjuvants for rainbow trout (Oncorhynchus mykiss).

Disease prevention by vaccination is, on economic, environmental and ethical grounds the most appropriate method for pathogen control currently available to the aquaculture sector. However, vaccine administration in aquatic animals faces obvious technical problems not encountered in other land animals. Thus, oral vaccines are highly demanded by the aquaculture sector that requests alternatives to the labor-intensive injectable vaccines that require individual handling of fish, provoking stress-related immunosuppression and handling mortalities.

Metabolic engineering for high yielding L(-)-carnitine production in Escherichia coli.

Background: L(-)-carnitine production has been widely studied because of its beneficial properties on various diseases and dysfunctions. Enterobacteria possess a specific biotransformation pathway which can be used for the enantioselective production of L(-)-carnitine. Although bioprocesses catalyzed by enzymes or whole cells can overcome the lack of enantioselectivity of chemical methods, current processes for L(-)-carnitine production still have severe disadvantages, such as the low yields, side reactions and the need of high catalyst concentrations and anaerobic conditions for proper expression of the biotransformation pathway.

Modelling and analysis of central metabolism operating regulatory interactions in salt stress conditions in a L-carnitine overproducing E. coli strain.

Based on experimental data from E. coli cultures, we have devised a mathematical model in the GMA-power law formalism that describes the central and L-carnitine metabolism in and between two steady states, non-osmotic and hyperosmotic (0.3 M NaCl).

Redirecting metabolic fluxes through cofactor engineering: Role of CoA-esters pool during L(-)-carnitine production by Escherichia coli.

Cofactor engineering, defined as the purposeful modification of the pool of intracellular cofactors, has been demonstrated to be a very suitable strategy for the improvement of L(-)-carnitine production in Escherichia coli strains. The overexpression of CaiB (CoA-transferase) and CaiC (CoA-ligase), both enzymes involved in coenzyme A transfer and substrate activation during the bioprocess, led to an increase in L(-)-carnitine production. Under optimal concentrations of inducer and fumarate (used as electron acceptors) yields reached 10- and 50-fold, respectively, that obtained for the wild type strain.