Plastic pollution is an increasing global issue desperately requiring a solution. Only 9% of all plastic waste has been recycled, and whilst recycling gives a second life to plastic, it is costly and there are limited downstream uses of recycled plastic, therefore an alternative is urgently needed. Biodegradation of plastic by microorganisms is a developing field of interest with the potential for bioreactors to be used alongside recycling to degrade plastic that may otherwise be sent to landfill. Here, we have identified two novel polyethylene terephthalate (PET) degrading enzymes through genomic mining and characterised their activity, including their ability to degrade PET. One of the main roadblocks facing the development of microbial enzymes as a plastic biodegradation solution, is that their efficiency is too low to facilitate development as bioremediation tools. In an innovative approach to tackle this roadblock, we hypothesised that enhancing a bacteria’s ability to attach to and form a biofilm on plastic could maximise the local concentration of the enzyme around the target substrate, therefore increasing the overall rate of plastic degradation. We found that increasing biofilm levels, by manipulating the levels of the second messenger, Cyclic-di-GMP, led to increased levels of polyester degradation in cells expressing novel and well characterised polyester-degrading enzymes. This indicates that modulating biofilm formation is a viable mechanism to fast track the development of bacterial plastic bioremediation solutions.

塑料污染是一个日益严重的全球性问题，迫切需要解决方案。所有塑料废物中只有 9% 得到了回收，虽然回收给塑料带来了第二次生命，但成本高昂，而且回收塑料的下游用途有限，因此迫切需要一种替代品。微生物对塑料的生物降解是一个正在发展的领域，生物反应器有可能与回收一起使用，以降解可能被送往垃圾填埋场的塑料。在这里，我们通过基因组挖掘鉴定了两种新型聚对苯二甲酸乙二醇酯 (PET) 降解酶，并表征了它们的活性，包括它们降解 PET 的能力。微生物酶作为塑料生物降解解决方案开发面临的主要障碍之一是其效率太低，无法促进作为生物修复工具的开发。在解决这一障碍的创新方法中，我们假设增强细菌附着在塑料上并形成生物膜的能力可以最大限度地提高目标底物周围酶的局部浓度，从而提高塑料降解的总体速率。我们发现，通过控制第二信使 Cyclic-di-GMP 的水平来增加生物膜水平，会导致表达新型且已充分表征的聚酯降解酶的细胞中聚酯降解水平的增加。这表明调节生物膜形成是快速跟踪细菌塑料生物修复解决方案开发的可行机制。