Natural methodologies for introducing desirable traits in food-grade LAB and Bacilli

External internship at NIZO


Lactic acid bacteria (LAB) are used in the production of dairy based products such as cheese and yoghurt. From the industry there is an incentive to develop and improve food-grade products that contain LAB.

Bacteria naturally use horizontal gene transfer to acquire new traits from their environment. Horizontal gene transfer can take place via three routes: (1) Phage transduction, (2) Conjugation and (3) Natural competence. Conjugation is the transfer of genetic material between bacterial cells via direct cell contact or by forming a pilus that connects two bacterial cells. Natural competence is a state in which bacteria are able to internalize external DNA and incorporate it into their genome or utilize it as an autonomous genomic agent (plasmid). Phage transduction can occur when bacteria encounter invasive bacteriophages that take up bacterial DNA instead of its own viral DNA. These transducing phage particles may subsequently transfer this bacterial DNA to another bacterial host.


In this project, we study horizontal gene transfer of mobile genetic elements. Using genomic data sets and in-silico tools we will identify novel mobile genetic elements which we try to subsequently transfer to different strains. By studying horizontal gene transfer, we will gain further insight into the frequencies of these occurrences  and elucidate the mechanisms behind them.


Expected techniques:

- Bacterial cell culture

- (q)PCR

- Genetic engineering tools, including DNA digestion, DNA ligation, DNA fragment purification,  transformation etc.

- (Fluorescent) Microscopy


This project is a collaboration between the WUR, NIZO, RUG and several industrial partners, however, this project will be performed at NIZO food research (Kernhemseweg 2, 6718 BE Ede). We are looking for a highly motivated student with experience in bacterial cell culture and molecular biology techniques who is able to work in this project for a minimum of 5 months. If you are looking for a challenge and you like the topic, do not hesitate to contact me so you can come over to discuss the project in more detail. We hope to hear from you!

Joyce Mulder

Contact Information