Scientists use “green” solvent and natural pi

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image: The process is sustainable (from right to left: vials containing astaxanthin, beta-carotene and a mixture of the two pigments extracted from the yeast P. rhodozyma)
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Scientists based in Brazil and Portugal have developed an environmentally sustainable process to produce biodegradable plastic using pigments extracted from yeast by “green” solvents. In an article published in the magazine Green chemistrythey show that this biodegradable plastic could in the future be used in smart packaging with antioxidant and antimicrobial properties.

With similar applications to conventional plastics derived from oil, gas and coal, which take hundreds of years to break down, sustainable bioplastics produced from sugar cane, corn and potatoes are beginning to be marketed.

After more than eight years of research, scientists have demonstrated that eutectic solvents can effectively extract two carotenoids, astaxanthin and beta-carotene, from yeast biomass. Phaffia rhodozyme.

Carotenoids are a class of over 750 natural pigments synthesized by plants, algae and photosynthetic bacteria. They explain the yellow, orange and red colors of many plants. They have commercial applications in the food, cosmetics and pharmaceutical industries, among others.

According to the researchers, the eutectic solvents can be used both to extract pigments and to produce a biodegradable plastic film based on bioactive starch without the need for further purification.

“We have demonstrated as proof of concept that it is possible to produce a natural pigment using a sustainable process. We worked with two lines. One was the production of yeast-based pigments and the extraction of these economically valuable natural compounds using eutectic solvents, which are a mixture of biocompatible and biodegradable components. The other was using the extracts to produce biomaterials such as starch-based bioplastic,” said Jorge Fernando Brando Pereiraprofessor in the Department of Chemical Engineering of the School of Science and Technology of the University of Coimbra in Portugal, and one of the corresponding authors of the article, alongside Cassamo Ussemane Mussagy.

FAPESP has supported research through four projects (20/08655-0, 19/15493-9, 18/06908-8 and 15/11759-3).

The research is part of Mussagy’s postdoctoral work at the University of São Paulo (USP) in collaboration with the State University of São Paulo (UNESP), under the supervision of Professor Adalberto Pessoa Junior.

“We looked for alternatives to synthetic pigments and extraction processes using polluting solvents. We have worked with sustainable methods to obtain natural pigments and apply them in the production of biodegradable plastic using green solvents,” Mussagy said. FAPESP Agency.

Pigments have been used for centuries to improve or restore the appearance of different products and ensure uniformity. As consumers increasingly seek healthier or more nutritious products, while trying not to harm the natural environment, synthetic pigments are being replaced by natural compounds that are environmentally friendly and also biologically active in the sense of antioxidant and antimicrobial properties.

According to the researchers, scientific studies aimed at the production or extraction of natural pigments from microorganisms will make it possible to expand the supply of bioplastics. Also known as biopolymers, these products currently make up less than 1% of the more than 367 million metric tons of plastic made globally each year, according to European bioplasticswhich represents the interests of approximately 70 member companies.

According to some estimates, the production of bioplastics will increase from 2.42 tons in 2021 to 7.59 million tons in 2026, in response to the increase in demand for alternative materials from the packaging, household appliances and textiles, as pressure increases to reduce the use of petroleum-derived plastics, due to pollution and non-degradable waste.

The development of new biopolymers is the focus of a research group led by Rondinelli Herculanprofessor at UNESP who collaborated in the development of the starch-based bioplastic.

Some 11 million tonnes of plastic were thrown away in Brazil in 2018, which corresponds to 13.5% of the year’s total waste and makes Brazil the world’s fourth largest producer of plastic waste. The estimate comes from the brazilian edition of plastic atlaspublished in November 2019 by the Heinrich Böll Foundation, a German NGO.

Plastic pollution is a growing threat to all ecosystems, especially the oceans, where it accounts for 85% of total waste, according to the United Nations.

“Industrial production processes are still aggressive even if the product is biodegradable,” Pereira said. “Paper, for example, is renewable and recyclable, but in almost all cases it is produced by unsustainable methods that consume huge amounts of energy, water and toxic chemicals. Our study demonstrates the possibility of obtaining bioplastics via an integrated and sustainable platform.

The process

Scientists produced the carotenoids by growing Phaffia rhodozyme in a bioreactor. They then used ionic liquids, choline-based eutectic solvents and butyric acid to extract the pigments from the yeast. Choline is a vitamin B-like nutrient produced by the human body and found in nature.

Ionic and eutectic liquids are considered ideal solvents for the extraction of compounds from natural matrices, mainly due to their capacity for solvation, a process by which solvent molecules surround and interact with ions or solute molecules. , or an ionic compound dissolves in a polar substance without forming a new one.

To maximize the recovery of astaxanthin (one of the most important natural antioxidants produced by yeasts and microalgae) and beta-carotene, the researchers tested five concentrations of biomass solvent (solid-liquid), considered as a key parameter in cell disruption procedures to recover intracellular molecules. from microbial biomass. The concentration that increased in both was up to 0.2 g mL-1 of wet yeast cells.

“We used the biosolvents so that the pigment was extracted from the yeast biomass and could be applied. We detected that the solvent with the best result both extracted the pigment from the biomass of the microorganism and also acted as a plasticizer for the packaging,” said Valeria de Carvalho Santos Ebinumaprofessor at UNESP and co-author of the “Hot Article” on green chemistry.

“Constant long-term investment is needed if we are to foster world-class research, so support from FAPESP is important,” Mussagy said. “After years of research into developing sustainable processes to produce and extract pigments from microbial sources, we have seen our work recognized by a scientific journal as one of the top 5% in the field of sustainability. ”

For Pereira, the multidisciplinary approach used in the study is important. “It is a reward for Mussagy’s constant efforts and shows the importance of synergy between institutions and researchers,” he said.

Mussagy said next steps will focus on applying the results to show that packaging with this type of “green” plastic can be used for a variety of purposes, including the food industry.

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About the São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution whose mission is to support scientific research in all areas of knowledge by granting scholarships, fellowships and grants to researchers linked to educational institutions University and Research from the State of São Paulo, Brazil. FAPESP is aware that the best research can only be done by working with the best researchers at the international level. Therefore, it has established partnerships with funding agencies, higher education institutions, private companies and research organizations in other countries known for the quality of their research and has encouraged scientists funded by its grants to further develop their international collaboration. You can find out more about FAPESP at www.fapesp.br/en and visit the FAPESP press agency at www.agencia.fapesp.br/en to keep abreast of the latest scientific advances that FAPESP helps to achieve through its many programs, prizes and research centers. You can also subscribe to the FAPESP press agency on http://agencia.fapesp.br/subscribe.


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