Jhonatan Hernandez-Valdes

Selection of microbial cells with increased product-yield for industrial fermentations

Jhonatan Hernandez-Valdes, room 5172.640 tel 32048 email This email address is being protected from spambots. You need JavaScript enabled to view it.


Many industrial fermentation processes aim at the production of primary or secondary metabolites, for instance the volatile flavor compounds in food fermentations. Because many of these target molecules are either extracellular or difficult to detect within a single cell, it is very challenging to select for individual mutants that produce increased amounts of the desired metabolite.

Our project focuses on the identification of individual Lactococcus lactis cells that produce an increased amount of chemical compounds with application in food industry. One example of these compounds is diacetyl, an aromatic compound, giving a buttery flavor to dairy products.


We aim to tackle the difficulties of product yield selection making use of micro-droplet culturing and microbial indicator strains, in order to select for mutants that produce increased amounts of industrially-relevant molecules. Indicator strains will be constructed with fluorescent reporters in combination with suitable promoters that are activated by the desired product.



Molecular biology techniques applied to Lactococcus lactis and Escherichia coli, flow cytometry, transcriptome analysis, microdroplets technology.


- Bachman H, Fischlechner M, Rabbers I, Barfa N, Santos F, Molenaar D, Teusink B (2013), Availability of public goods shapes the evolution of competing metabolic strategies. Proceedings of the National Academy of Sciences of the United States of America, 110(35), 14302–7
- Bachmann, H. and Teusink B. (2011) A method for the adaptive evolution of a cell and selection for a desired phenotype by serial propagation in an emulsion based system and uses thereof. WO2012EP50068 20120104

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