‘Villain’ bacteria from citrus farming could become ‘heroine’ in the production of biorenewables

The Xanthomonas bacterium, responsible for citrus canker, has always been known as an enemy of crops due to the damage it causes to citrus farming. But studies that have just been published reveal valuable details for the development of new technologies to be applied in the use of agro-industrial waste and contribute to a more sustainable economy.

The same biological processes used by bacteria to weaken some of the most important plant defense systems, now better studied, prove to be very useful in enabling not only the production of biofuels, but several other more complex raw materials that the chemical industry needs to the manufacture of paints, plastics, acids, solvents and many other products that are currently still obtained almost exclusively from petroleum derivatives.

The revelation comes from a study by scientists from the National Center for Research in Energy and Materials (CNPEM), a social organization linked to the Ministry of Science, Technology and Innovations (MCTI), in collaboration with researchers from the University of São Paulo and the University of Campinas (Unicamp) which has just been published in Nature Communications.

Over five years, a wide range of scientific resources available in the CNPEM research ecosystem were used, such as synchrotron beamlines (LNLS), genomic, transcriptomic, genetic engineering (LNBR) approaches and in vivo experimentation on plants at the National Laboratory of Biosciences (LNBio), in addition to specialized human resources and international reference, which made this discovery possible.

Discoveries

The research uncovered an unknown class of enzymes that the bacterium Xanthomonas mobilizes to deconstruct the cell wall of plants and, when invading the cells, induce the production of proteins that enhance infection. This new class of enzymes was named CE20, an acronym for Carbohydrate Esterase family 20.

According to the researchers, the efficiency of the enzymes' work is due to their exceptional ability to act on chemical bonds and degrade one of the most complex carbohydrates in the cell wall, xyloglucan.

"These discoveries provide us with new alternatives to increase the capacity to use plant biomass in biorefineries, which are very valuable from a biotechnological point of view. And by revealing new components of the bacteria's virulence we can collaborate with the development of new strategies to combat the disease , with the design of potential inhibitors for this group of bacteria that are so relevant to Brazilian agriculture", explains Mario Murakami, research coordinator and scientific director of the National Biorenewables Laboratory (LNBR).

The elucidation of the structure and its biochemical functioning is knowledge that can be combined with other microbial platform solutions under development at CNPEM, such as the one built from the enzyme cocktail produced by the Fungus RUT-C30. A customized platform for the reality of Brazil, tested in an industrially relevant environment and with a patent filed, which makes it possible to set up biorefineries to obtain advanced sugars, that is, those obtained from lignocellulosic materials such as agro-industrial waste, valuable for the production of products with greater added value in a sustainable way.

With the support of the São Paulo State Research Support Foundation (Fapesp), CNPEM has developed several studies that have been internationally recognized for their impact on enabling processes that can accelerate the industrial production of bioproducts for different economic segments. More sophisticated biochemicals and materials, with high performance and efficiency, greater added value and lower environmental impact, replacing a large part of the inputs of fossil origin currently used in industry.