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

Abstract

High-temperature-active microbial enzymes are important biocatalysts for many industrial applications, including recycling of synthetic and biobased polyesters increasingly used in textiles, fibers, coatings and adhesives. Here, we identified three novel thermotolerant carboxylesterases (IS10, IS11, and IS12) from high-temperature enrichment cultures from Ischia hydrothermal vents and incubated with biobased polymers.

The Impact of Metagenomics on Biocatalysis

“…Therefore, many hydrolases that are discovered (mostly esterases) come from more extreme environments. [78][79][80] The Ward group discovered a new set of epoxide hydrolase (EH) enzymes from a soil metagenome, which was chosen due to previously isolated EHs displaying activity on soil contaminants. [81] Mining their in-house database of over 42,000 metagenomic sequences led to new 3 limonene epoxide hydrolases (LEHs) and 30 α/β-EH sequences being identified and characterised that accepted a wide variety of aromatic, aliphatic and meso-epoxides.…”

The Impact of Metagenomics on Biocatalysis

“…Therefore, many hydrolases that are discovered (mostly esterases) come from more extreme environments. [78][79][80] The Ward group discovered a new set of epoxide hydrolase (EH) enzymes from a soil metagenome, which was chosen due to previously isolated EHs displaying activity on soil contaminants. [81] Mining their in-house database of over 42,000 metagenomic sequences led to new 3 limonene epoxide hydrolases (LEHs) and 30 α/β-EH sequences being identified and characterised that accepted a wide variety of aromatic, aliphatic and meso-epoxides.…”

Amino Acid Self-Regenerating Cell-Free Protein Synthesis System that Feeds on PLA Plastics, CO2, Ammonium, and α-Ketoglutarate

“…Since (i) the global production of PLA is quickly growing and (ii) the natural degradation of PLA can take decades (although much faster than polyethylene), there is an urgent need to develop efficient recycling/upcycling technologies instead of time-consuming composting and incineration that result in CO 2 production. Up until to date, many studies have described microbial PLA degradation ,, that would generate CO 2 during the PLA mineralization, while enzymatic depolymerization represents a rather “greener” approach, ,− which only generates lactate as the sole product, and the produced lactate can be purified by removing the enzymes via immobilization. Furthermore, the immobilized enzymes can be recycled for further enzymatic depolymerization.…”

“…In the enzyme-based metabolic cascade, DL-PLA serves a dual purpose of (i) an electron donor for NADH regeneration (from the LDH reaction) to initiate the reductive amination step in the AA biosynthesis 38 and (ii) a precursor of AAs (via the central metabolite pyruvate). Furthermore, to break down PLA for generating free lactate for AA synthesis in a PURE system, we introduced an mRNA encoding the recently reported PLA hydrolase (IS12; PLAase), 32 resulting in a "PLA-eating" PURE system. Cell-free synthesis of the PLAase incorporating PLAderived AAs allowed the breakdown of externally supplied PLA 1A), which will then be fed back into a PUREfrex for mRNA translation.…”

“…Furthermore, the immobilized enzymes can be recycled for further enzymatic depolymerization. Among the three PLA isomeric forms ( l l , d d , d l ), the racemic form ( d l -form) and the l l -form can be effectively depolymerized by several carboxylesterases ,, and Tritirachium proteinase K (not compatible with the cell-free systems due to its proteolytic activities), respectively. As such, d l -PLA represents a low-cost, sustainable feedstock for cell-free protein synthesis because its monomer (lactate) can undergo a single-step enzymatic conversion into the central metabolite pyruvate via the NAD + -dependent lactate dehydrogenase (LDH) for subsequent AA synthesis.…”