(From left to right). Leila Satari, Alba Guillén, Àngela Vidal-Verdú and Manuel Porcar.

The team led by Manuel Porcar, researcher at the Institute of Integrative Systems Biology (I2SysBio, a joint center of the University of Valencia and the CSIC) has received an IG Nobel Prize for unusual research for its work on the bacterial load contained in chewing gum stuck on the ground for weeks and the evolution of the same, in five different countries. The article was signed in October 2020 in Scientific Reports, signed by Leila Satara, Alba Guillén, Ángela Vidal-Verdú and Manuel Porcar himself.

The IG Nobel, awarded on September 9, are a parody of the prestigious Nobel Prizes –in fact, they are awarded on close dates– and are promoted by the editors of the scientific humor magazine Annals of Improbable Research. Since 1991, they have rewarded research that first makes you laugh, but that makes you think. The work led by Manuel Porcar has received the award in the 'Ecology' category.

“It has been a surprise to receive the IG Nobel Prize, but we also see it as a recognition of the original and potentially fun task of many ecologists and people who participate in bioprospecting and who spend our lives traveling with a sterile tube in our suitcases to take samples from all over the world and contribute to expanding the arsenal of microbial strains and natural products that have a huge range of industrial and biomedical," explains Manuel Porcar.

According to the researcher, "chewing gum could be vectors of bacterial diseases long after being thrown on the ground. We have found bacteria that can be used to clean chewing gum, because they eat it!" The expert adds that "chewing gum has a bacterial load that evolves from an oral microbiome to an environmental one in a matter of weeks. Oral bacteria last a surprisingly long time once the gum is on the ground. In addition, many of the bacteria that we have isolated from older gum have the potential to bioremediate the chewing gum, that is, degrade it."

The I²SysBio research team points out that these long-lasting residues have been used. for human genetic analysis in criminology and archaeology, and also highlights that their findings have implications for a wide range of disciplines, including forensic medicine, the control of contagious diseases or the already mentioned bioremediation of chewing gum residue.

The research also demonstrated that the bacterial load of chewing gum changes in a matter of weeks and that oral bacteria last a surprisingly long time when the gum is on the ground. This research can be applied in forensic medicine or control of contagious diseases.

The study focused on the distribution of bacteria according to the depth at which they are found (superficial, intermediate and lower layers of the residue), the biodegradation capacity of the chewing gum ingredients and the microbial successions after spending three months of exposure to the open air. The bacterial diversity of the samples has been analyzed through Massive DNA Sequencing (NGS).

Chewing gum is waste that remains for a long time on indoor and outdoor surfaces, stuck on buildings or even on works of art. For this study the team collected a total of ten samples, two in Spain, France and Singapore, and one in Greece and Turkey. All were collected from the ground with a sterilized scraper and transported to the laboratory, where they were preserved at a temperature of -80 ºC until analysis.

The article signed by Leila Satara, Alba Guillén, Ángela Vidal-Verdú and Manuel Porcar describes a complete characterization of the bacterial content of the chewing gum using culture-dependent and independent techniques, unlike other research that focuses on improving the cleaning of chewing gum thrown on the ground, making them fewer adhesives, water-soluble or degradable. Furthermore, the team highlights that this adhesive material “may contain an important fraction of the oral microbiota, toxins and some pathogens such as Streptococcus spp. and Actinomyces spp., which remain trapped in the sticky residue and where their survival over time has received very little attention.”

Article: Satari, L., Guillén, A., Vidal-Verdú, À. et al. «The wasted chewing gum bacteriome». Sci Rep 10, 16846 (2020). https://doi.org/10.1038/s41598-020-73913-4

Ceremony of the IG Nobel Prize 2021, here.