Biology subjects

Sanz, D.

Publications and source records attributed to Sanz, D..

3 recordsLinked to original sources

bioRxiv2026

Integrated valorisation of PET and xylose using the oleaginous microorganisms Yarrowia lipolytica and Rhodococcus jostii

The increasing accumulation of polyethylene terephthalate (PET) waste has prompted the development of sustainable biotechnological strategies for its degradation and valorisation. This study presents an integrated approach combining enzymatic PET depolymerization by Yarrowia lipolytica, engineered to express and secrete the cutinase HiC and the lipase CalB, with the microbial valorization of PET-derived monomers, terephthalic acid (TPA) and ethylene glycol (EG), by Rhodococcus jostii RHA1. Y. lipolytica was further engineered for xylose metabolism, enabling enzyme production from low-cost lignocellulose-derived substrates. Enzymatic assays with HiC and CalB crudes effectively hydrolysate PET to TPA and EG, demonstrating functional enzymatic activity without purification steps. In addition, R. jostii RHA1 was able to use as substrate the released monomers and accumulated intracellular lipids. Overall, this work demonstrates the feasibility of coupling the production of PET degrading enzymes and microbial lipid, using an abundant monosaccharide, with the assimilation of the PET degradation products to also produce microbial lipids. This modular system provides a promising framework for the sustainable upcycling of plastic waste into value-added bioproducts within a circular economy.

synthetic biology↗

bioRxiv2025

Biochemical Upcycling of PET via Glycolysis and Engineered Microbial Consortia

Polyethylene terephthalate (PET) waste remains a major environmental challenge due to its recalcitrance and low economic value. Here, we present an integrated biochemical approach that couples glycolysis with a synthetic microbial consortium to upcycle post-consumer PET (pcPET) into polyhydroxyalkanoates (PHA). Glycolysis efficiently depolymerized pcPET into bis(2-hydroxyethyl) terephthalate (BHET) in 2 h, circumventing the limitations of in vivo PET degradation. We engineered a two-species microbial consortium composed of Comamonas testosteroni RW31, able to metabolise terephthalic acid, and Pseudomonas putida JM37, able to consume ethylene glycol, each modified for the extracellular secretion of PET- and MHET-hydrolases, employing different plasmid architectures. This division of labour enabled rapid BHET hydrolysis and the subsequent upcycling of the released monomers into PHAs. The combination of the different strains allowed to select C. testosteroni pSEVA354-MHETase and P. putida pSEVA234-PETase as the best consortium, based on growth and PHAs content. Overall, this work proposes a strategy for PET waste depolymerisation and valorisation, highlighting the potential of mixed chemical and biological approaches and the use of non-conventional microbial chassis within engineered consortia.

synthetic biology↗

bioRxiv2025

Pseudomonas putida JM37 as a novel bacterial chassis for ethylene glycol upcycling

Ethylene glycol (EG), one of the main monomers of polyethylene terephthalate (PET), is an attractive target for microbial upcycling. Despite this interest, there is a limited number of described organisms that can efficiently metabolise EG. Here, we report the metabolic and biotechnological potential of Pseudomonas putida JM37 as a novel bacterial chassis for EG valorization. We show that JM37 efficiently grows on EG as the sole carbon and energy source, outperforming other Pseudomonas strains. Genome sequencing and directed mutagenesis revealed that genetic redundancies in the glyoxylate assimilation pathways underlie its robust EG metabolism. Beyond biomass generation, we demonstrated the biotechnological potential of JM37. This strain was able to accumulate medium-chain polyhydroxyalkanoates (mcl-PHAs), dominated by C10 monomers, directly from EG. Moreover, JM37 successfully expressed heterologous biosynthetic pathways, including a violacein biosynthetic operon and a PET-hydrolase which has been secreted actively into the extracellular medium. Together, our results support the use of P. putida JM37 as a versatile synthetic biology chassis for sustainable EG upcycling and as a promising platform for circular bioproduction.

synthetic biology↗