Dutra Molino João Vitor, Saucedo Barbara, Kang Kalisa, Walsh Chloe, Diaz Crisandra Jade, Tessman Marissa, Simkovsky Ryan, Mayfield Stephen
Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
Algenesis Inc., 1238 Sea Village Dr., Cardiff, CA, USA.
Sci Rep. 2025 Jul 9;15(1):24690. doi: 10.1038/s41598-025-09100-0.
Plastic pollution has become a global crisis, with microplastics contaminating every environment on the planet, including our food, water, and even our bodies. In response, there is a growing interest in developing plastics that biodegrade naturally, thus avoiding the creation of persistent microplastics. As a mechanism to increase the rate of polyester plastic degradation, we examined the potential of using the green microalga Chlamydomonas reinhardtii for the expression and secretion of PHL7, an enzyme that breaks down post-consumer polyethylene terephthalate (PET) plastics. We engineered C. reinhardtii to secrete active PHL7 enzyme and selected strains showing robust expression, by using agar plates containing a polyester polyurethane (PU) dispersion as an efficient screening tool. This method demonstrated the enzyme's efficacy in degrading ester bond-containing plastics, such as PET and bio-based polyurethanes, and highlights the potential for microalgae to be implemented in environmental biotechnology. The effectiveness of algal-expressed PHL7 in degrading plastics was shown by incubating PET with the supernatant from engineered strains, resulting in substantial plastic degradation, confirmed by mass spectrometry analysis of terephthalic acid formation from PET. Our findings demonstrate the feasibility of polyester plastic recycling using microalgae to produce plastic-degrading enzymes. This eco-friendly approach can support global efforts toward eliminating plastic in our environment, and aligns with the pursuit of low-carbon materials, as these engineered algae can also produce plastic monomer precursors. Finally, this data demonstrates C. reinhardtii capabilities for recombinant enzyme production and secretion, offering a "green" alternative to traditional industrial enzyme production methods.
塑料污染已成为全球危机，微塑料污染着地球上的每一个环境，包括我们的食物、水，甚至我们的身体。作为应对措施，人们对开发可自然生物降解的塑料越来越感兴趣，从而避免产生持久性微塑料。作为提高聚酯塑料降解速率的一种机制，我们研究了利用绿色微藻莱茵衣藻表达和分泌PHL7的潜力，PHL7是一种可分解消费后聚对苯二甲酸乙二酯（PET）塑料的酶。我们对莱茵衣藻进行基因工程改造，使其分泌活性PHL7酶，并通过使用含有聚酯聚氨酯（PU）分散体的琼脂平板作为高效筛选工具，筛选出表达强劲的菌株。该方法证明了该酶在降解含酯键塑料（如PET和生物基聚氨酯）方面的功效，并突出了微藻在环境生物技术中应用的潜力。通过将PET与工程菌株的上清液孵育，显示了藻类表达的PHL7在降解塑料方面的有效性，质谱分析PET形成的对苯二甲酸证实了大量的塑料降解。我们的研究结果证明了利用微藻生产塑料降解酶进行聚酯塑料回收的可行性。这种环保方法可以支持全球消除环境中塑料的努力，并且符合对低碳材料的追求，因为这些工程藻类还可以生产塑料单体前体。最后，这些数据证明了莱茵衣藻生产和分泌重组酶的能力，为传统工业酶生产方法提供了一种“绿色”替代方案。
