Understanding and enhancing plastics biodegrdation

减少塑料对我们环境的影响是一项迫切的任务，需要新的根本和技术解决方案。解决方案的一部分是开发“更好的”塑料，针对其预期用途进行良好设计，并提供适当的寿命结束选项。这将包括由可再生资源制成的可堆肥和可回收材料，其成本和性能可与目前基于石油的同类材料相媲美，甚至更好。因此，在过去的几年里，对生物基和/或非耐久塑料，即所谓的生物塑料的需求不断增加。聚乳酸是一种以生物为基础的聚酯，是可降解生物塑料的旗舰。由于其性能和长期的发展，对聚乳酸的需求越来越大。该公司目前在全球的年产量约为435kt，预计到2026年产能将增加80%。至关重要的是，在过去的15年里，关于其寿命终结选择的声明发生了变化，从可生物降解(意味着在自然条件下完全降解为二氧化碳、水和生物质)到工业可堆肥(在受控条件下的降解，包括60摄氏度以上的温度、控制的湿度和选定的微生物)，突显了人们对聚乳酸和生物塑料的降解程度的了解和关注。尽管做出了重大努力，但聚乳酸在工业堆肥条件下的生物降解率仍然很低，降低了其在堆肥设施中的接受度(例如，当聚乳酸用于一次性可堆肥包装并与混合食物垃圾一起收集时)。在家庭堆肥或土壤中(例如，当被放置在环境中)，聚乳酸在可持续的时间内不存在生物降解。在这个项目中，我们将设计定制的聚合物添加剂来加强聚乳酸的堆肥。(例如，通过促进微生物生长来加快生物降解过程)。我们建议，不仅开发聚合物添加剂，而且将它们与新设计的微生物和酶结合起来，这些微生物和酶能够更好地发挥作用(例如，速度更快，耐高温)，或者能够产生有用的和附加值的化学品(例如，新聚合物的起始块，产生的堆肥的营养物质)。最终，我们建议的技术将加强聚乳酸的堆肥，为生物塑料的生物降解带来新的基本理解，并将有助于在循环经济中发挥其潜力。

Reducing the impact of plastics on our environment is an urgent task that needs new fundamental and technological solutions. Part of the solution is to develop "better" plastics,well-designed for their intended use and with appropriate end-of-life options. This will include compostable and recyclable materials made from renewable resources at a cost and performance comparable to, or even better than, current petro-based equivalents. Thus, the past few years have seen an increasing demand for bio-based and/or non-durable plastics, so-called bioplastics.Poly(lactic acid), or PLA, is a bio-based polyester and the flagship of degradable bioplastics.Due to its properties and long-standing development, there is an increasing demand for PLA. Its annual production is currently at ~435 kT worldwide and an expected production capacity increase of 80% is predicted by 2026. Crucially, the change in claims regarding its end of life options over the past 15 years, from being biodegradable (implying complete degradation to CO2, water and biomass in natural conditions) to industrially compostable (degradation incontrolled conditions, including temperatures above 60 degree centigrade, controlled humidity and selected microorganisms) highlight how much the degradation of PLA, and bioplastics in general, is poorly understood and requires attention.Despite significant efforts, the biodegradation rate of PLA in industrial compost conditions remains low, reducing its acceptance in composting facilities (e.g. when PLA is used in disposable compostable packaging and collected along with mixed food waste). In home compost or soil (e.g. when deposited in the environment), PLA biodegradation is inexistent over a sustainable timeframe.In this project, we will design bespoke polymeric additives to enhance the composting of PLA. (e.g. by promoting microorganism growth to speed up the biodegradation process). We propose, not only to develop polymeric additives, but also to combine them with newly engineered microorganisms and enzymes able to work "better" (e.g. faster, tolerant to higher temperatures) or able to lead to useful and added-values chemicals (e.g. starting blocks for new polymers, nutriments for the resulting compost).Ultimately, our proposed technologies will enhance the composting of PLA, bring new fundamental understanding to bioplastic biodegradation and will contribute to enabling their potential within a circular economy.