Thermophilic Carboxylesterases from Hydrothermal Vents of the Volcanic Island of Ischia Active on Synthetic and Biobased Polymers and Mycotoxins

Hydrothermal vents are geographically widespread and host microorganisms with robust enzymes useful in various industrial applications. We examined microbial communities and carboxylesterases of two terrestrial hydrothermal vents of the volcanic island of Ischia (Italy) predominantly composed of Firmicutes, Proteobacteria, and Bacteroidota. High-temperature enrichment cultures with the polyester plastics polyhydroxybutyrate and polylactic acid (PLA) resulted in an increase of Thermus and Geobacillus species and to some extent Fontimonas and Schleiferia species. The screening at 37 to 70°C of metagenomic fosmid libraries from above enrichment cultures identified three hydrolases (IS10, IS11, and IS12), all derived from yet-uncultured Chloroflexota and showing low sequence identity (33 to 56%) to characterized enzymes. Enzymes expressed in Escherichia coli exhibited maximal esterase activity at 70 to 90°C, with IS11 showing the highest thermostability (90% activity after 20-min incubation at 80°C). IS10 and IS12 were highly substrate promiscuous and hydrolyzed all 51 monoester substrates tested. Enzymes were active with PLA, polyethylene terephthalate model substrate, and mycotoxin T-2 (IS12). IS10 and IS12 had a classical a/b-hydrolase core domain with a serine hydrolase catalytic triad (Ser155, His280, and Asp250) in their hydrophobic active sites. The crystal structure of IS11 resolved at 2.92 Å revealed the presence of a N-terminal b-lactamase-like domain and C-terminal lipocalin domain. The catalytic cleft of IS11 included catalytic Ser68, Lys71, Tyr160, and Asn162, whereas the lipocalin domain enclosed the catalytic cleft like a lid and contributed to substrate binding. Our study identified novel thermotolerant carboxylesterases with a broad substrate range, including polyesters and mycotoxins, for potential applications in biotechnology. Copyright © 2023 Distaso et al.This study was conducted under the auspices of the FuturEnzyme Project funded by the European Union’s Horizon 2020 Research and Innovation Program under grant agreement 101000327. M.F. and F.J.P. also acknowledge grants PID2020-112758RB-I00 (M.F.), PDC2021- 121534-I00 (M.F.), TED2021-130544B-I00 (M.F.), and PID2019-105838RB-C31 (F.J.P.) from MCIN/AEI/10.13039/501100011033 and the European Union (“NextGenerationEU/PRTR”). M.A.D., T.N.C., R.B., A.N.K., O.V.G., A.F.Y., and P.N.G. are thankful for support fromthe European Regional Development Fund (ERDF) through the Welsh Government to the Centre for Environmental Biotechnology, project number 81280. P.N.G. and A.F.Y. acknowledge the Natural Environment Research Council UK-funded Plastic Vectors project NE/S004548/1 and the Sêr Cymru program partly funded by the ERDF through the Welsh Government for support of the project BioPOL4Life.We are indebted to Connie Tulloch and GwionWilliams for their technical support.Supporting InformationPeer reviewe

Corrigendum: High representation of archaea across all depths in oxic and low-pH sediment layers underlying an acidic stream

In the original article, there was a mistake. The incorrect Figure 1 was published..

Development of ophthalmic training simulator for cataract surgery

Purpose: development of interactive simulator for the development of phacoemulsification. Material and Methods. Material and methods: the Software developed by the authors ophthalmic virtual simulator has several modules that can also be complemented by depending on put before the students the task. Testing the virtual simulator "Phacoemulsification" held at the Department of ophthalmology with the participation of 20 interns and 18 residents. Results. The development of residents and interns of ophthalmological profile of the theoretical foundations of cataract surgery using developed by the authors of the publication virtual interactive simulator demonstrated the effectiveness of this technique in comparison with passive viewing of video recording operations and the familiarity with the course of phacoemulsification in the operating room. Conclusion. The application of the developed simulator with the purpose of optimization of educational process of residents and interns of ophthalmic profile is a very effective tool in the world today.</p