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

RUI：协作：研究 PET 塑料废物细菌降解的真正方法

• 批准号: 1931150
• 负责人: Jay Mellies
• 金额: $ 68.44万
• 依托单位: Reed College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1931150&HistoricalAwards=false
• 关键词: RUI; Collaborative; REAL; Approach; Investigating

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.

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，因此这项研究的重点是我们环境中发现的塑料的生物降解。为了创造一个更循环的塑料经济，研究人员之前分离出了一个细菌物种的财团，总共有五个，可以降解聚对苯二甲酸乙二醇酯（PET），这种材料用于制造塑料水瓶。结果发现，总的来说，该聚生体比单独的聚生体或物种生长得更快，并且产生更多的塑料降解酶活性。该项目需要确定这些观察的遗传和生物化学基础。该项目为本科生和高中生提供旨在实现研究计划目标的研究机会。第一代和代表性不足的少数民族学生被招募进行夏季研究，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。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估计63亿公吨中的一部分。三种假单胞菌和两种芽孢杆菌。先前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。发现五种细菌的聚生体协同作用，比单个聚生体或菌株更快地产生更多的脂肪酶活性来降解PET塑料。本项目研究了该菌群降解过程的机理。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NMR技术来确定PET和相关化合物的分解产物，以确定该分解过程所需的酶和遗传途径。转座子诱变是一种无偏的方法，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分析用于确定聚生体成员的调控网络与PET降解所需的遗传途径之间的相互作用。该项目利用RNA测序技术，研究了酯键断裂和对苯二甲酸及乙二醇完全降解所需的聚生体细菌的基因调控网络。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。