RUI: Collaborative: A REAL Approach to Investigating Bacterial Degradation of PET Plastic Waste

减少、再利用和回收计划很重要，但不足以解决我们地球面临的巨大塑料污染问题，因此这项研究集中在我们环境中发现的塑料的生物降解上。为了创造更循环的塑料经济，研究人员之前分离出了一个细菌物种联合体，总共五种，它们能降解塑料水瓶所用的材料聚对苯二甲酸乙二酯(PET)。结果发现，与单独的联合体或物种相比，联合体生长得更快，产生的塑料降解酶活性更多。该项目需要确定这些观察的遗传和生化基础。该项目为本科生和高中生提供研究机会，旨在实现研究计划的目标。第一代和代表性不足的少数族裔学生被招募进行暑期研究和在学年继续努力。细菌降解PET的遗传基础也将在普通微生物学课程的实验室部分进行研究，以丰富课程内容。土壤细菌对PET塑料的协同降解尚未得到探索，但有可能帮助去除环境中目前存在的约63亿吨塑料中的一部分。假单胞菌3株，芽孢杆菌2株。以前从德克萨斯州休斯顿附近的石油污染土壤中通过筛选与塑料降解有关的脂肪酶活性而分离到。五种细菌的组合被发现具有协同作用，在降解PET塑料方面产生更多的脂肪酶活性，比单独的组合或菌株更快。本项目研究该联合体的细菌降解过程的机理。在KEGG通路数据库的帮助下，该项目涉及挖掘这五种细菌的基因组，以了解PET生物降解所需的代谢途径。该项目使用核磁共振技术来确定PET和相关化合物的分解产物，以努力确定这种分解过程所需的酶和遗传途径。转座子突变是一种无偏见的方法，用于识别编码脂肪酶、酯酶和其他与PET降解有关的酶的基因。RNAseq分析用于确定联盟成员的调控网络与PET降解所需的遗传途径之间的相互作用。通过使用RNA测序，该项目调查了酯键断裂和对苯二甲酸和乙二醇完全降解所需的联合细菌的遗传调控网络。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Reduce, reuse and recycle programs are important, but are not enough to address the massive plastic pollution problem facing our planet, and thus this research is focused on the biodegradation of plastics found in our environment. Toward creating a more circular plastic economy, the investigators previously isolated a consortium of bacterial species, five in total, that degrade polyethylene terephthalate (PET), the material used to make plastic water bottles. It was discovered that, collectively, the consortium grew faster on, and produced more plastic-degrading enzyme activity than individual consortia or species alone. This project entails determining the genetic and biochemical basis for these observations. The project provides undergraduate and high school students research opportunities aimed at accomplishing the goals of the research plan. First generation and underrepresented minority students are recruited for summer research and continued effort during the academic year. The genetic basis for bacterial degradation of PET also will be investigated in the laboratory portion of a general microbiology course, providing enrichment the curriculum. Synergistic degradation of PET plastic by soil bacteria is unexplored but has the potential to aid in the removal of a portion of the estimated 6.3 billion metric tons that currently exist in the environment. Three Pseudomonas and two Bacillus spp. were previously isolated from petroleum polluted soils near Houston, TX, by screening for lipase activity which is associated with plastic degradation. The consortium of five bacterial species were found to act synergistically, producing more lipase activity in degrading PET plastic faster than individual consortia or strains. This project investigates the mechanism of the bacterial degradation process by the consortium. With the assistance of the KEGG pathways database, the project involves mining the genomes of the five bacteria to understand the metabolic pathways necessary for biodegradation of PET. The project uses NMR techniques to determine the breakdown products of PET and related compounds in an effort to identify the enzymes and genetic pathways necessary for this decomposition process. Transposon mutagenesis, an unbiased approach, is used to identify genes encoding lipases, esterases and other enzymes involved in PET degradation. RNAseq analysis is used to determine the interactions between the regulatory networks of the consortia members and the genetic pathways necessary for PET degradation. With the use of RNA sequencing, the project investigates the genetic regulatory network of the consortium bacteria required for ester bond cleavage and the complete degradation of terephthalic acid and ethylene glycol.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.