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，但不足以解决我们星球面临的大规模塑料污染问题，因此本研究的重点是我们环境中发现的塑料的生物降解。为了创造一个更加循环的塑料经济，研究人员之前分离出了一个细菌群落，总共有五种，可以降解聚乙烯对苯二甲酸乙二醇酯（PET），这种材料用于制造塑料水瓶。人们发现，总的来说，这个联合体比单独的联合体或物种生长得更快，并产生更多的塑料降解酶活性。这个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。第一代和未被充分代表的少数民族学生被招募参加暑期研究，并在学年期间继续努力。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探索，但有可能帮助去除目前存在于环境中的约63亿吨塑料中的一部分。通过筛选与塑料降解相关的脂肪酶活性，从德克萨斯州休斯顿附近的石油污染土壤中分离到三种假单胞菌和两种芽孢杆菌。五种细菌的联合体被发现协同作用，产生更多的脂肪酶活性降解PET塑料比单个联合体或菌株更快。本项目通过联合体研究细菌降解过程的机制。在KEGG途径数据库的帮助下，该项目涉及挖掘五种细菌的基因组，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，以确定分解过程所需的酶和遗传途径。转座子诱变是一种无偏倚的方法，用于鉴定编码脂肪酶、酯酶和其他参与PET降解的酶的基因。RNAseq分析用于确定财团成员的调控网络与PET降解所需的遗传途径之间的相互作用。通过RNA测序，该项目研究了酯键裂解和对苯二甲酸和乙二醇完全降解所需的联合体细菌的遗传调控网络。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.