# Iron-mediated interaction of the cheese ripening bacteria B. aurantiacum and H. alvei

Rina Mekuli, Dominique Swennen, Sarah Chuzeville, Sophie Landaud

► To cite this version:

Rina Mekuli, Dominique Swennen, Sarah Chuzeville, Sophie Landaud. Iron-mediated interaction of the cheese ripening bacteria B. aurantiacum and H. alvei. 14th International Symposium on Lactic Acid Bacteria, Aug 2023, Egmond aan Zee, Netherlands. 2023. hal-04440506

HAL Id: hal-04440506

https://hal.inrae.fr/hal-04440506

Submitted on 6 Feb 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.
<figure><img src="image_1.png" /></figure>

# Ripening bacteria mutually depend on each other to access iron and nitrogen sources in cheese.

## IRON-MEDIATED INTERACTION OF THE CHEESE RIPENING BACTERIA

### B. aurantiacum AND *H. alvei*

Rina Mekuli(1), Dominique Swennen(1), Sarah Chuzeville(2), Sophie Landaud(1)

Contact: rina.mekuli@inrae.fr

## INTRODUCTION

* Cheese is an **iron scarce** environment.

* As a cofactor to many enzymes, notably as iron sulphur clusters, its scarcity affects **a range of metabolic pathways**, including respiration in ripening bacteria.

* Siderophores – iron chelating compounds secreted under iron starvation – may be **shared amongst the community**.

## RESEARCH OBJECTIVES

* Investigate cell perturbation under iron **abundance** and **scarcity** in two cheese ripening bacteria.

* Explore the potential link between **iron** and **sulphur compounds** - main aromatics in cheese.

* Understand if **sharing siderophores** alleviates the stress exerted by iron insufficiency.

* Observe variations in **pigmentation** across these conditions.

## RESULTS

* Lower growth of *H. alvei* in synthetic medium containing caseins as a nitrogen source indicates that *H. alvei* depends on the protease activity of *B. aurantiacum*.

* Lower growth of *B. aurantiacum* in iron depleted (EDDHA) synthetic medium indicates that *B. aurantiacum* depends on siderophores produced by *H. alvei*.

<figure><img src="image_2.png" /></figure>

<figure><img src="image_3.png" /><figcaption>Growth in amino acids vs. caseins</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>Growth in iron scarcity vs. abundance</figcaption></figure>

## FUTURE EXPERIMENTS

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /></figure>

* Cultivate both strains as **monocultures** and **coculture** in iron abundant and iron scarce mediums in batch bioreactors.

* Metabolomic, transcriptomic and proteomic data collection to understand the changes happening to the cells at several levels.

* Incorporate experimental data **to Genome Scale Metabolic Models (GSMMs)** of the single organisms and coculture. Use the GSMMs to gain understanding on the **flux distributions**, **metabolic interactions** and **dependencies** in the coculture.

<figure><img src="image_9.png" /></figure>

Growth data

<figure><img src="image_10.png" /></figure>

Extracellular metabolites

<figure><img src="image_11.png" /></figure>

Transcriptome

<figure><img src="image_12.png" /></figure>

Proteome

<figure><img src="image_13.png" /></figure>

<footnote>(1) INRAE, AgroParisTech, Université Paris-Saclay, UMR SayFood, Palaiseau, France</footnote>

<footnote>(2) Actalia, Dairy Microbiology, Eteaux, France</footnote>
<figure><img src="image_1.png" /></figure>

# Ripening bacteria mutually depend on each other to access iron and nitrogen sources in cheese.

## IRON-MEDIATED INTERACTION OF THE CHEESE RIPENING BACTERIA

### B. aurantiacum AND *H. alvei*

Rina Mekuli(1), Dominique Swennen(1), Sarah Chuzeville(2), Sophie Landaud(1)

Contact: rina.mekuli@inrae.fr

## INTRODUCTION

* Cheese is an **iron scarce** environment.

* As a cofactor to many enzymes, notably as iron sulphur clusters, its scarcity affects **a range of metabolic pathways**, including respiration in ripening bacteria.

* Siderophores – iron chelating compounds secreted under iron starvation – may be **shared amongst the community**.

## RESEARCH OBJECTIVES

* Investigate cell perturbation under iron **abundance** and **scarcity** in two cheese ripening bacteria.

* Explore the potential link between **iron** and **sulphur compounds** - main aromatics in cheese.

* Understand if **sharing siderophores** alleviates the stress exerted by iron insufficiency.

* Observe variations in **pigmentation** across these conditions.

## RESULTS

* Lower growth of *H. alvei* in synthetic medium containing caseins as a nitrogen source indicates that *H. alvei* depends on the protease activity of *B. aurantiacum*.

* Lower growth of *B. aurantiacum* in iron depleted (EDDHA) synthetic medium indicates that *B. aurantiacum* depends on siderophores produced by *H. alvei*.

<figure><img src="image_2.png" /><figcaption>H. alvei</figcaption></figure>

<figure><img src="image_3.png" /><figcaption>Growth in amino acids vs. caseins</figcaption></figure>

<figure><img src="image_4.png" /><figcaption>Growth in iron scarcity vs. abundance</figcaption></figure>

## FUTURE EXPERIMENTS

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

<figure><img src="image_8.png" /></figure>

* Cultivate both strains as **monocultures** and **coculture** in iron abundant and iron scarce mediums in batch bioreactors.

* Metabolomic, transcriptomic and proteomic data collection to understand the changes happening to the cells at several levels.

* Incorporate experimental data **to Genome Scale Metabolic Models** (GSMMs) of the single organisms and coculture. Use the GSMMs to gain understanding on the **flux distributions**, **metabolic interactions** and **dependencies** in the coculture.

<figure><img src="image_9.png" /></figure>

Growth data

<figure><img src="image_10.png" /></figure>

Extracellular metabolites

<figure><img src="image_11.png" /></figure>

Transcriptome

<figure><img src="image_12.png" /></figure>

Proteome

<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>

<footnote>(1) INRAE, AgroParisTech, Université Paris-Saclay, UMR SayFood, Palaiseau, France</footnote>

<footnote>(2) Actalia, Dairy Microbiology, Eteaux, France</footnote>