Project Description

Mitigating the impact of drought with alginate


A new record

This year, France set a new record!

Our country had its most extended episode without rain at the beginning of the year, surpassing the previous record set in 1989 with 22 consecutive days without rain. This time, the drought lasted for 32 days.

However, behind this information lies a more worrying reality. Throughout France, the soils are much drier than they should be at this time of the year. Some regions, such as Roussillon, Aude, and Pyrénées-Orientales are particularly affected by this situation. Worldwide, in 2022, more than 2.3 billion people faced water stress, and around 160 million children faced severe and prolonged droughts.

Food security concerns

This drought is a cause for concern, as it negatively impacts daily life. Agriculture is directly affected, with reduced harvests and difficulties for farmers to maintain their activities. Local flora and fauna are also suffering, compromising the ecological balance of these regions. It is difficult to provide an accurate figure for economic losses caused by drought in France, as it depends on many factors that differ yearly such as loss of farm income, additional costs for irrigation, damage to infrastructure, impact on tourism, and so on.

According to some estimates, annual losses due to drought in France can vary from several hundred million euros to several billion euros, depending on the intensity and duration of the drought and the specific sectors affected. For example, during the summer 2019, agricultural losses were estimated at over 1 billion euros, mainly due to reduced crop yields and animal feed problems. Unfortunately, forecasts for the next few years are hardly encouraging. By 2030, an estimated 700 million people could be relocated by drought; by 2050, droughts could affect more than three-quarters of the world's population.

It is crucial to take action to address this situation and adapt to ongoing climate change. That's why our team from the University of Aix-Marseille is working on a project called Terralgi. The aim is to find solutions for maintaining optimum soil moisture levels during periods of drought in order to limit the impact on agriculture of long periods without rain.

Our solution

Drought mitigation

Our project, of global and local scope, is therefore part of a desire to maintain the humidity on the soil the best we can. This process would reduce the amount needed of water during heat waves, therefore allowing us to maintain the groundwater already diminished.

Our main objective is to use synthetic biology to produce a biological system able, once introduced into the "chassis" bacteria, to produce an unlimited amount of alginate using recycled waste. This molecule will be used to create calcium alginate beads.

Simultaneously, this project aims to increase awareness of our issue among a wide range of individuals, including students, residents of Marseille, and the broader French population, at the very least, with the goal of expanding globally if feasible. Our objective is to showcase the hardships faced by our local farmers, thereby educating as many people as possible about the broader implications of this issue, which extends beyond the agricultural domain.

Boosting the alginate production

Firstly, we are going to work in the production, purification, and testing of the alginate created by our chosen bacteria: Pseudomonas Putida KT2440.
Alginate is a polysaccharid which can be used to form hydrogels able to retain a great quantity of water. It is used today in various domains such as healthcare and food processing industry. Using it to retain water has already been explored 1 but produced from farmed algae, it is too costly (~3000$/ton) to be used at scale. Furthermore, its extraction and purification can use a lot of toxic chemicals 2. Thus, our first goal will be to reduce the cost and environmental impact of alginate production, using bacteria instead of algae. We will work on overproducing alginate in Pseudomonas Putida KT2440, a non-pathogenic bacteria naturally producing alginate. For that, we built a mutator plasmid to inhibit the mucA gene

A calcium-based hydrodel

In the process of developing our hydrogel, we have made a deliberate decision to utilize calcium ions for gel formation. This choice is driven by several factors, including the comparatively non-toxic nature of calcium to both soils and plants, its widespread availability, and its affordability. Additionally, we are committed to exploring methods for recycling calcium from waste sources, further enhancing the sustainability of our approach.

Figure 1 : Calcium alginate beads

Standardizing alginate beads

We want our product to be used and for that we talked with our future users: people working in agriculture. Their feedback convinced us to the need of standardizing our alginate beads and we buit and iterated on a mold for that. Moving forward, we will focus on optimizing this chosen product by conducting comprehensive tests to determine the ideal size and concentration.

Safety and safety

What sets our product apart from other hydrogels on the market is that it is both environmentally friendly and harmless to health.

Unlike the industrial method, which uses brown algae to produce alginate, our approach of the overproduction of alginate in Pseudomonas Putida offers better control over the physicochemical properties of alginate. We have also chosen to focus on the production of alginate as a responsible alternative to mitigate the risks of worker overexploitation and labor augmentation associated with the excessive use of brown and red algae. It is crucial for us to remain vigilant and ensure that our purchasing decisions do not support industries that exploit their valuable workforce. By prioritizing the production of alginate, we are committed to upholding ethical practices and maintaining a sustainable supply chain. Our product suits today's sustainability and environmental preservation expectations thanks to its ecological properties.

Safety is a top priority for us. Our hydrogel has been rigorously studied to ensure that it poses no health risk. We understand the importance of providing a safe product that guarantees our customers' worry-free use.


  1. Bacterial Alginate-Based Hydrogel Reduces Hydro-Mechanical Soil-Related Problems in Agriculture Facing Climate Change , C. Barrientos-Sanhueza et al, Polymers. (2022). doi: 10.3390/polym14050922
  2. A Brief Review on the Development of Alginate Extraction Process and Its Sustainability, S. Saji et al, Sustainability. (2022). doi: 10.3390/su14095181