Carr Clodagh M, de Oliveira Bruno Francesco Rodrigues, Jackson Stephen A, Laport Marinella Silva, Clarke David J, Dobson Alan D W
School of Microbiology, University College Cork, Cork, Ireland.
SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland.
Front Microbiol. 2022 Apr 12;13:888343. doi: 10.3389/fmicb.2022.888343. eCollection 2022.
Many marine bacteria produce extracellular enzymes that degrade complex molecules to facilitate their growth in environmental conditions that are often harsh and low in nutrients. Marine bacteria, including those inhabiting sea sponges, have previously been reported to be a promising source of polyesterase enzymes, which have received recent attention due to their potential ability to degrade polyethylene terephthalate (PET) plastic. During the screening of 51 marine bacterial isolates for hydrolytic activities targeting ester and polyester substrates, a B129SM11 isolate from the deep-sea sponge sp. was identified as a polyesterase producer. Sequence analysis of genomic DNA from strain B129SM11, coupled with a genome "mining" strategy, allowed the identification of potential polyesterases, using a custom database of enzymes that had previously been reported to hydrolyze PET or other synthetic polyesters. This resulted in the identification of a putative PET hydrolase gene, encoding a polyesterase-type enzyme which we named BgP that shared high overall similarity with three well-characterized PET hydrolases-LCC, TfCut2, and Cut190, all of which are key enzymes currently under investigation for the biological recycling of PET. protein analyses and homology protein modeling offered structural and functional insights into BgP, and a detailed comparison with Cut190 revealed highly conserved features with implications for both catalysis and substrate binding. Polyesterase activity was confirmed using an agar-based polycaprolactone (PCL) clearing assay, following heterologous expression of BgP in . This is the first report of a polyesterase being identified from a deep-sea sponge bacterium such as and provides further insights into marine-derived polyesterases, an important family of enzymes for PET plastic hydrolysis. Microorganisms living in association with sponges are likely to have increased exposure to plastics and microplastics given the wide-scale contamination of marine ecosystems with these plastics, and thus they may represent a worthwhile source of enzymes for use in new plastic waste management systems. This study adds to the growing knowledge of microbial polyesterases and endorses further exploration of marine host-associated microorganisms as a potentially valuable source of this family of enzymes for PET plastic hydrolysis.
许多海洋细菌会产生细胞外酶，这些酶能降解复杂分子，以利于它们在通常恶劣且营养匮乏的环境条件下生长。此前有报道称，包括栖息在海海绵中的细菌在内的海洋细菌是聚酯酶的一个有前景的来源，由于其潜在的降解聚对苯二甲酸乙二酯（PET）塑料的能力，聚酯酶最近受到了关注。在对51株海洋细菌分离株进行针对酯和聚酯底物的水解活性筛选过程中，从深海海绵物种中分离出的一株B129SM11被鉴定为聚酯酶产生菌。对菌株B129SM11的基因组DNA进行序列分析，并结合基因组“挖掘”策略，利用一个先前已报道能水解PET或其他合成聚酯的酶的定制数据库，鉴定出了潜在的聚酯酶。这导致鉴定出一个假定的PET水解酶基因，该基因编码一种聚酯酶类型的酶，我们将其命名为BgP，它与三种特征明确的PET水解酶——LCC、TfCut2和Cut190具有高度的总体相似性，这三种酶都是目前正在研究用于PET生物循环利用的关键酶。蛋白质分析和同源蛋白建模为BgP提供了结构和功能方面的见解，与Cut190的详细比较揭示了对催化和底物结合都有影响的高度保守特征。在BgP在中进行异源表达后，使用基于琼脂的聚己内酯（PCL）清除试验证实了聚酯酶活性。这是首次从深海海绵细菌如中鉴定出聚酯酶的报道，并为海洋来源的聚酯酶提供了进一步的见解，这是一类对PET塑料水解很重要的酶。鉴于海洋生态系统被这些塑料广泛污染，与海绵共生的微生物可能更容易接触到塑料和微塑料，因此它们可能是用于新的塑料废物管理系统的有价值的酶来源。这项研究增加了对微生物聚酯酶的认识，并支持进一步探索与海洋宿主相关的微生物，作为这一家族用于PET塑料水解的潜在有价值的酶来源。
