Biodegradation of Polymers at Temperatures up to 130°C

Marine enzymes: Classification and application in various industries

Oceans are regarded as a plentiful and sustainable source of biological compounds. Enzymes are a group of marine biomaterials that have recently drawn more attention because they are produced in harsh environmental conditions such as high salinity, extensive pH, a wide temperature range, and high pressure. Hence, marine-derived enzymes are capable of exhibiting remarkable properties due to their unique composition. In this review, we overviewed and discussed characteristics of marine enzymes as well as the sources of marine enzymes, ranging from primitive organisms to vertebrates, and presented the importance, advantages, and challenges of using marine enzymes with a summary of their applications in a variety of industries. Current biotechnological advancements need the study of novel marine enzymes that could be applied in a variety of ways. Resources of marine enzyme can benefit greatly for biotechnological applications duo to their biocompatible, ecofriendly and high effectiveness. It is beneficial to use the unique characteristics offered by marine enzymes to either develop new processes and products or improve existing ones. As a result, marine-derived enzymes have promising potential and are an excellent candidate for a variety of biotechnology applications and a future rise in the use of marine enzymes is to be anticipated.

Enhanced Extracellular Expression of a Ca2+- and Mg2+-Dependent Hyperthermostable Protease EA1 in Bacillus subtilis via Systematic Screening of Optimal Signal Peptides

Proteases have been widely applied in various industries, including tanning, silk, feed, medicine, food, and environmental protection. Herein, the protease EA1 (GenBank accession no. U25630.1) was successfully expressed in Bacillus subtilis and demonstrated to function as a Ca²⁺- and Mg²⁺-dependent hyperthermostable neutral protease. At 80 °C, its half-life (t_1/2) in the presence of 10 mM Mg²⁺ and Ca²⁺ was 50.4-fold longer than that in their absence (7.4 min), which can be explained by structural analysis. Compared with the currently available commercial proteases, protease EA1 has obvious advantages in heat resistance. The largest peptide library was used to enhance the extracellular expression of protease EA1 via constructing and screening 244 signal peptides (SPs). Eleven SPs with high yields of protease EA1 were identified from 5000 clones using a high-throughput assay. Specifically, the enzyme activity of protease produced by the strain (217.6 U/mL) containing the SP XynD was 5.2-fold higher than that of the strain with the initial SP. In brief, the protease is a potential candidate for future use in the high-temperature industry.

Isolation, cloning, and overexpression of a chitinase gene fragment from the hyperthermophilic archaeon Thermococcus chitonophagus: semi-denaturing purification of the recombinant peptide and investigation of its relation with other chitinases

A 189-bp sequence was isolated from the hyperthermophilic archaeon Thermococcus chitonophagus and was found to present strong homology with a large number of chitinase genes from a variety of organisms and particularly with the chitinaseA gene from Pyrococcus kodakaraensis (Pk-chiA). This fragment was subcloned to an expression vector and overexpressed in Escherichia coli. The E. coli BLR21(DE3)pLysS transformant, harbouring the gene on the pET-31b plasmid vector, was found to overproduce the target protein at high levels. The 63 aminoacid-long peptide was efficiently purified to homogeneity, with a one-step, semi-denaturing affinity chromatography, on a metal chelation resin and was used for the production of a specific, polyclonal antibody from rabbits. The produced antibody was demonstrated to display strong and specific affinity for the chitinase A from Serratia marcescens (Sm-chiA), as well as the membrane-bound chitinase70 from Thermococcus chitonophagus (Tc-Chi70). The strong sequence homology, in combination with the demonstrated specific immunochemical affinity, indicates that the isolated peptide is part of a chitinolytic enzyme of T. chitonophagus. In particular, it could belong to the membrane-bound chi70, or to a distinct chitinase, coded by a different gene, or even by the same gene, following post-transcriptional or post-translational modifications.