Biology subjects

Cifuentes-Anticevic, J.

Publications and source records attributed to Cifuentes-Anticevic, J..

2 recordsLinked to original sources

bioRxiv2026

Polar Marine Microbial Communities as Reservoirs of Polyester Degrading Enzymes

BackgroundPolyethylene terephthalate (PET) is one of the most widely used plastics and a major contributor to marine pollution. While the diversity of PET hydrolases (PETases), which degrade PET into mono(2-hydroxyethyl) terephthalate (MHET), terephthalate (TPA) and ethylene glycol, has been documented in temperate and tropical waters, their potential presence in polar oceans remain unascertained. ResultsHere, we systematically screened polar and non-polar marine metagenomes using Hidden Markov models (HMM) generated using experimentally validated PETases. We identified >680 putative PETase-like sequences, with Antarctic and Arctic candidates enriched in high-fidelity motifs associated with PETase-like activity. Phylogenetic and structural analyses defined a high-confidence PETase-like clade comprising both Type I and Type II enzymes, differing in thermostability-related features and PET-binding motifs. Experimental assays confirmed polyesterase activity in 5/9 candidates from this clade, including polar-derived variants active at 14-25{degrees}C. Downstream enzymes for PET consumption were also widespread, detecting 209 putative MHET hydrolases and 442 TPA-catabolyzing enzymes. Further, we reconstructed 112 metagenome-assembled genomes (MAGs) carrying at least one PETase-like gene, more than half from polar datasets. Notably, 15 MAGs encoded multiple PETase-like enzymes, and 1 Antarctic MAG harbored a complete PETase-MHETase-TPA pathway, evidencing a fully integrated degradation potential in cold-adapted taxa. ConclusionsTogether, these results demonstrate that polar oceans act as previously overlooked reservoirs of taxonomically and functionally diverse plastic-degrading enzymes. The enrichment of PETase-like enzymes and downstream pathways in polar microbial communities expands the global biogeography of plastic biodegradation and highlights cold-active enzymes as promising candidates for developing low-temperature plastic bioremediation strategies.

bioinformatics↗

bioRxiv2024

Genomic and proteomic characterization of sulfate-reducing symbionts of gutless marine annelids

Sulfate-reducing bacteria (SRB) are widespread in marine and terrestrial environments, where they often form syntrophic associations with bacteria, archaea, and eukaryotes. Among the most intimate of these are multipartite symbioses in gutless marine oligochaete worms, which host SRB and sulfur-oxidizing endosymbionts that engage in a syntrophic exchange of sulfur compounds. Despite decades of research on free-living SRB, the metabolic traits that enable SRB to persist in symbiosis, and how these differ across hosts and environments, remain poorly understood. Here, we show that a globally distributed clade of symbiotic SRB has a conserved core metabolism that diverges markedly from free-living relatives. Using comparative genomics and metaproteomics, we reveal that these endosymbionts retain key traits of SRB such as sulfate reduction, complete oxidation of acetate to CO2, amino acid degradation for nitrogen acquisition, and transport of essential nutrients. However, they exhibit a more oxygen-tolerant metabolism and lack typical nutrient-scavenging mechanisms of free-living SRB. One symbiont-specific trait, the glyoxylate bypass, was consistently expressed in situ and may serve both in reactive oxygen species defence and in biomass generation. The enrichment and expression of oxygen-tolerant pathways, coupled with the loss of nutrient-scavenging functions, indicate specialization to a host-associated, redox-fluctuating environment distinct from that of free-living SRB. Consistent with this shift, symbiont genomes are larger than those of free-living relatives, contrasting with genome reduction in many endosymbionts and reinforcing the importance of metabolic versatility. Our findings provide a framework for understanding how metabolic flexibility enables SRB to persist in long-term multipartite symbioses across diverse marine ecosystems.

microbiology↗