Predicting and Quantifying the Biodegradability of biopolymers

该项目旨在开发一个新的框架来预测和量化生物聚合物的生物降解性，比目前的测试更准确。人们越来越有兴趣使用生物聚合物，如几丁质、纤维素和淀粉，作为全球工业和消费品原料中化石燃料衍生的合成聚合物的替代品。据设想，从化石燃料转向由许多生物（如植物）生产的天然聚合物，可以帮助消除化学生产对气候变化的影响。近年来，消费化学和产品行业增加了合成聚合物的产量，目前每年至少生产1.4亿吨（Siracusa, 2019）。这些聚合物用于从塑料到化妆品和药品以及个人卫生产品的所有产品中（Shah等人，2008年）。随着人口持续增长，到2100年将达到97亿（联合国，2019年），未来几十年对这类产品的需求可能会增加。因此，评估这些聚合物在生产期间和处置后对自然环境的影响变得越来越重要。目前使用的大多数聚合物都是通过原油的分馏生产的，这一过程与温室气体的释放有关，从而导致气候变化。此外，其中一些聚合物在进入自然海洋或陆地环境时可能对野生动物产生不利影响，从而破坏生物多样性。人们希望使用这些生物聚合物生产的化学产品将比目前的合成产品更具可生物降解性，从而对生态系统的稳定性或生物多样性的总体影响很小。然而，人们对这些聚合物的可生物降解性知之甚少，如何测试它们的可生物降解性仍然存在一些不确定性。现有的许多规范性生物降解试验已有30多年的历史，其设计目的是评估小分子量、低分子量的化学品，它们对评估较大、更复杂的聚合物的适用性尚未得到充分评估。此外，还需要开发能够快速评估聚合物生物降解可能性的筛选工具，以指导上游创新。现有测试的局限性突出了我们对如何测量聚合物生物降解的理解的研究差距。转向生物聚合物具有改善气候变化和生物多样性丧失这两个问题的巨大潜力，然而，在将其大规模处置到环境中之前，对其生物降解性进行预测和量化是至关重要的。这将涉及使用生物信息学工具来识别生物降解聚合物感兴趣的酶途径以及能够催化这些途径的酶的范围。然后将使用微生物生态学技术来确定在相关环境（即聚合物处置后的最终归宿）中产生这些酶的微生物的相对丰度。还将对一些现有的生物降解测试进行调整，以便将这些测试结合起来形成一个有凝聚力的框架，可以可靠地预测和量化聚合物的生物降解性。

This project aims to develop a new framework for predicting and quantifying the biodegradability of biopolymers with greater accuracy than current testing allows.There is increasing interest in the use of biopolymers such as chitin, cellulose and starch as alternatives to the synthetic polymers derived from fossil fuel as feedstock for global industrial and consumer products. It is envisaged that switching from fossil fuels to natural polymers, which are produced by many living organisms such as plants, can help to negate climate change impacts of chemical production.In recent years, the consumer chemical and products industry has increased its production of synthetic polymers, with at least 140 million tons now being produced every year (Siracusa, 2019). These polymers are used in everything from plastics to cosmetics and pharmaceuticals as well as personal hygiene products (Shah et al., 2008). With the human population still growing and set to reach 9.7 billion by 2100 (UN, 2019), demand for such products is likely to increase over the next few decades. It is becoming increasingly important therefore to assess the impact of these polymers on the natural environment, both during their production and after their disposal. At present most polymers in use are produced through the fractional distillation of crude oil, a process that is associated with the release of greenhouse gases thereby contributing to climate change. Additionally, some of these polymers may have adverse effects on wildlife when they enter the natural marine or terrestrial environments, damaging biodiversity as a result.It is hoped that chemical products produced using these biopolymers will be more biodegradable than the current synthetic ones and so will have little impact on the stability of ecosystems or biodiversity in general. However, little is known about how biodegradable these polymers are, and there remains some uncertainty as how to test their biodegradability. The many regulatory biodegradation tests that exist are more than 30 years old and were designed to assess small, low molecular weight chemicals and their applicability for assessing larger, more complex polymers has not adequately been assessed. In addition, there is a need to develop screening tools that allow for rapid assessment of the likelihood of polymer biodegradation in order to guide upstream innovation.Limitations to existing tests highlight a research gap in our understanding of how to measure biodegradation in polymers. The switch to biopolymers has great potential to ameliorate the twin issues of climate change and biodiversity loss however, it is crucial that their biodegradability can be predicted and quantified before they are disposed at scale into the environment.This will involve using bioinformatics tools to identify enzymatic pathways of interest for biodegrading polymers and the range of enzymes capable of catalysing these pathways. Microbial ecology techniques will then be used to determine the relative abundance of microbes that produce these enzymes in the relevant environments (i.e. where the polymers will end up after disposal). Adaptations will also be made to some existing biodegradation tests so these can be combined to form a cohesive framework that can reliably predict and quantify the biodegradability of polymers.