Safety: Not an option

Safety is a top priority for us.

Our project aims to improve the food security of the world and thus the human well-being: we can't compromise with safety to attain this goal.

That's why our hydrogel has been rigorously researched to ensure it poses no health risk.

Hence, since the beginning of the project, one of the reasons behind the choice of alginate was its environmental friendliness

A safe strain

Most of bacterial alginate studies are done either with A. vinelandii or P. aeruginosa. At the beginning of the project we chose to work on P. aeruginosa, in part because researchers we knew tended to work with it.

However, P. aeruginosa is pathological. To accomodate our safety requirements, we chose to switch to a bacteria close to P. aeruginosa, but not pathological: P. putida

The strain pseudomonas Putida (KT2440) is frequently isolated from most temperate soils and waters and is mainly known to recycle organic wastes. It is a well-characterized organism and is classified by the FDA as HV1 certified, indicating it is safe to use in a P1 or ML1 environment. Therefore, the strain is considered Safe, or GRAS. In addition, putida is regarded as a plant growth-promoting rhizobacterium, and some strains have antibacterial and antifungal properties

Using our strain safely

At the beginning of the project, we had two choices: either we worked on producing alginate from bacteria in lab and then we put the alginate in the soil, or we worked on producing alginate directly in the soil. We chose the first option because of the safety issues raised about disseminating GMOs in the environment

A safe hydrogel

The alginate we will purify is also entirely safe for use. Although we will make tests and ask health professionals to test our purified alginate form once produced at scale, the molecule already has various uses in biomedicine (like wound healing, drug delivery, and tissue engineering applications). It is also known to possess multiple applications in the food and nutraceutical industries, such as food gels, controlled-release systems, and film packaging, or to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing, or emulsifying agent.

To ionize the alginate and give it a hydrogel form, many products could have been used (Mg2+ < Mn2+ < Zn2+, Ni2+, Co2+< Fe2+ < Ca2+ < Sr2+ < Ba2+ < Cd2+ < Cu2+ < Pb2+) but we decided to use calcium since it is the most common cation, easy to find in huge quantity and not too pricey. We also found that it was used in the food industry since it helps extend the shelf life of a wide variety of food products while maintaining desirable texture and flavor properties. It is used in salt processing to add a salty taste to pickles and other foods without increasing sodium content. As far as food goes, calcium chloride is regarded as a safe preservative according to the FDA

Better yet: a safer hydrogel

Overall, calcium alginate is non-toxic and environmentally friendly compared to traditional alginate production.

In fact, the hydrogels found in the market on the plant's alley are created with anionic polyacrylamide. After detecting foodborne acrylamide in 2002, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) concluded in 2005 that acrylamide could pose a risk to human health (FAO/WHO, 2005). Studies on the characterization of exposure based on concentrations measured in food show that the average doses of acrylamide in the general population vary from 0.3 to 0.8 μg/kg body weight per day (FAO/ WHO, 2002). Between 2011 and 2012, another survey conducted by EFSA on certain acrylamide-contributing products (cited above) showed that 12 foods out of 157 samples tested had an acrylamide content above the guide values.

In humans, acrylamide is absorbed through the oral, respiratory, and cutaneous routes. It is distributed throughout the body and eliminated in the urine. The exposure biomarkers most frequently used to assess recent exposure (a few days) of the occupational population to acrylamide are the assays of urinary acrylamide metabolites. In this case, the best biomarker of exposure is N-acetylcysteine-S-propionamide (NACP) (Hays & Aylward, 2008). However, the measurement of hemoglobin adducts is a better biomarker to reflect slightly earlier exposure, i.e., those of the last three months (DeWoskin et al. 2013). The studies are few, but they document possible harmful effects of acrylamide on the nervous system during exposure to acrylamide; in fact, workers exposed to concentrations greater than 0.3mg/m3 over 8 hours have an increased prevalence of peripheral neurological symptoms compared to those exposed to less than 0.3mg/m3. In addition, the International Agency for Research on Cancer (IARC) classified acrylamide as probably carcinogenic to humans (group 2A). The EU has classified acrylamide in category 2 (substances that should be treated as carcinogenic to humans).

Designed in a safe environment

In the lab itself, we have been advised by multiple experts on alginate or gene modification, and we have been warned of the possible risks of mutation (nontoxic again), so we decided to change our plans.

We also followed a training at LISM with modules on chemical and biological risks, which had to be validated before starting any manipulations.

The lab can accommodate six people, and we also have two offices for the analytical part. We have access to all the machines in the building, with explanations on how to use them. We are trying as much as possible to use recycled products to grow our Pseudomonas and are actively researching new ways to reuse molecules and waste (to act as our calcium, for example).