There are millions of tons of lignocellulosic and cellulosic waste every year as a result of agricultural activities. How amazing would it be to be able to transform this waste material to something useful?

There are several ways this can be done. For example, lignocellulose can be discomposed by using a combination of physical, chemical and enzymatical treatments, resulting in compounds that can be used for microbial fermentations and biosynthesis of chemicals. This process can be even more cost-effective if several different lignocellulose substrates can be discomposed into a single compound, or if they can simultaneously lead to two or more valuable compounds.

Pseudomonas putida is a bacteria that can naturally use a range of aromatic compounds and organic acids, but that is only able to use a few compounds derived from plant biomass (such as glucose, mannose and fructose). Nevertheless, through genetic engineering scientists have managed to get this bacteria to use other substrates derived from plant biomass. For example, there is a strain of P. putida able to grow on mixtures of D-glucose, d-cellobiose and d-xylose. However, although this strain is able to metabolize this mixture of carbohydrates, is doesn’t generate any added value compounds (only biomass and CO2).

This research focuses on the development of a P. putida strain that is able to grow on D-xylose and produce D-xylonate, that is then released to the exterior of the cell. Xylonate is a very interesting molecule from a biotechnological point of view, as it can be used as a complexing agent or chelator, as a precursor of polyesters, or as an inexpensive alternative for d-gluconic acid. This strain is also able to valorize D‐cellobiose, by converting it into medium‐chain‐length polyhydroxyalkanoates, which are biodegradable polyesters that can be used for manufacturing of packaging materials, textile or medical implants.

Check out the full article here, recently published in Microbial Biotechnology: