Evaluation of PET Degradation Using Artificial Microbial Consortia

Abstract

Polyethylene terephthalate (PET) biodegradation is regarded as an environmentally friendly degradation method. In this study, an artificial microbial consortium composed of Rhodococcus jostii, Pseudomonas putida and two metabolically engineered Bacillus subtilis was constructed to degrade PET. First, a two-species microbial consortium was constructed with two engineered B. subtilis that could secrete PET hydrolase (PETase) and monohydroxyethyl terephthalate hydrolase (MHETase), respectively; it could degrade 13.6% (weight loss) of the PET film within 7 days. A three-species microbial consortium was further obtained by adding R. jostii to reduce the inhibition caused by terephthalic acid (TPA), a breakdown product of PET. The weight of PET film was reduced by 31.2% within 3 days, achieving about 17.6% improvement compared with the two-species microbial consortium. Finally, P. putida was introduced to reduce the inhibition caused by ethylene glycol (EG), another breakdown product of PET, obtaining a four-species microbial consortium. With the four-species consortium, the weight loss of PET film reached 23.2% under ambient temperature. This study constructed and evaluated the artificial microbial consortia in PET degradation, which demonstrated the great potential of artificial microbial consortia in the utilization of complex substrates, providing new insights for biodegradation of complex polymers.

Merging Plastics, Microbes, and Enzymes: Highlights from an International Workshop

“…Recently, methods and protocols to set up the selection and cultivation of aerobic and anaerobic PDC were reported ( 90 ). Other strategies for the design of microbial consortia with plastic-degrading capacities have been proposed using “bottom-up” approaches ( 91 , 92 ). There are still many challenges to developing, using, preserving, and commercializing these types of consortia, and more research is needed in this field ( 31 ).…”

Current Advances in the Biodegradation and Bioconversion of Polyethylene Terephthalate

“…Artificial microbial consortia that simulate natural microbial consortia to complete complex biological processes have become an important research topic in synthetic biology [86,89,149,150]. It is important to explore the potential and reprogram the functionality of microbial consortium members for specific approaches, especially for the bioconversion of contaminants [151,152].…”

“…Although PHB could not be synthesized directly from PET because of the low hydrolyzing efficiency of PETase, it demonstrated the possibility of artificial microbial consortia achieving the simultaneous degradation and upcycling of PET [106]. Our laboratory has constructed a four-species microbial consortium composed of two metabolically engineered B. subtilis, Rhodococcus jostii and P. putida to degrade PET, and the weight loss of PET film reached 23.2% under ambient temperature [149]. The artificial microbial consortium successfully relieved the metabolic inhibition of TPA and EG, and effectively improved the degradation rate [149].…”

“…Our laboratory has constructed a four-species microbial consortium composed of two metabolically engineered B. subtilis, Rhodococcus jostii and P. putida to degrade PET, and the weight loss of PET film reached 23.2% under ambient temperature [149]. The artificial microbial consortium successfully relieved the metabolic inhibition of TPA and EG, and effectively improved the degradation rate [149].…”

“…Artificial microbial consortia can be used to perform more complex tasks in a more complex environment [178][179][180][181]. Constructing a PET-degrading module, an EG-converting module, and a TPA-converting module to perform different functions can accelerate the degradation of PET and realize the complete conversion of it [149]. Artificial microbial consortia can couple the depolymerization of PET by secreted enzymes with the biosynthesis of high value chemicals from monomers, which is a promising strategy in realizing the circular economy of PET waste [106].…”