Periodic Reporting for period 1 - ACTPAC (A Complete Transformation PAth for C-C backboned plastic wastes to high-value Chemicals and materials)
Reporting period: 2024-01-01 to 2025-06-30
Context: Plastic pollution has become a clear threat to many environmental niches and ecosystems, due to rapidly increasing use of plastic products and leakage to the environment. Polyethylene (PE) is the most widely used and the largest-volume plastic (c.a. 30% of total plastics). Due to the absence of reactive groups, the C-C backboned plastics are often categorized as non-degradable; generally disposed by incineration or landfill (67%). About 12% plastic wastes are recycled as the goods with inferior quality and performance. The real catalytic route for upcycling of PE wastes into value-added products is <1%. It is clear that there is an urgent need to develop new routes for innovative upcycling of plastic wastes towards a paradigm shift in the plastic economy.
Overall objectives: ACTPAC proposes a complete value-added industry-viable path to convert PE firstly into alkanes; then into high- value chemicals (monomers); and finally, into PE-like but fully biodegradable polyesters. Beyond the state-of-the art technologies, ACTPAC will design and deploy new catalysts and cross-metathesis modes for highly active and selective metathesis of PE into linear alkanes with a narrow distribution range (C6-C18, >90%). Two separate systems: multi-enzyme machinery assembled in the recombinant cells, and metabolic engineered yeast system, dedicated to the transformation of alkanes into monomers will be developed. Monomers of diversified chain-lengths will be used for the synthesis of polyesters presenting different properties and polymer performances, assignable for various applications.
At the end of the project, a zero-waste solution to the plastic waste management will then be created to keep them out of the environment, and reclaim their values. The new properties and specific applications of the new polyester plastics produced from upcycling of PE waste will bring up the SMEs with new business opportunities by scalable, flexible and robust multi-product manufacturing processes for on-demand and small-volume output production.
Overall objectives: ACTPAC proposes a complete value-added industry-viable path to convert PE firstly into alkanes; then into high- value chemicals (monomers); and finally, into PE-like but fully biodegradable polyesters. Beyond the state-of-the art technologies, ACTPAC will design and deploy new catalysts and cross-metathesis modes for highly active and selective metathesis of PE into linear alkanes with a narrow distribution range (C6-C18, >90%). Two separate systems: multi-enzyme machinery assembled in the recombinant cells, and metabolic engineered yeast system, dedicated to the transformation of alkanes into monomers will be developed. Monomers of diversified chain-lengths will be used for the synthesis of polyesters presenting different properties and polymer performances, assignable for various applications.
At the end of the project, a zero-waste solution to the plastic waste management will then be created to keep them out of the environment, and reclaim their values. The new properties and specific applications of the new polyester plastics produced from upcycling of PE waste will bring up the SMEs with new business opportunities by scalable, flexible and robust multi-product manufacturing processes for on-demand and small-volume output production.
Total 9 deliverables have been submitted as scheduled in the grant agreement. The main achievements are listed as follows:
1) Two catalytic systems (Ru/TiH2 and CeO2-promoted Pt/zeolite) were developed and tested. Hydrogenolysis of LDPE over Ru/TiH2 achieved ~75% PE conversion and ~37% selectivity toward the C6–C18 fraction. Hydrocracking of LDPE over Pt/zeolite achieved complete PE conversion and ~15% selectivity toward the C6–C18 fraction.
2) 6 different CYP153 monooxygenase orthologs were screened, and CYP153A33 and CYP153A71 demonstrated highest diol and diacid production, towards C6-C12 range of alkanes. As for auxiliary enzymes, Putidaredoxin reductase (PdR) and putidaredoxin (PdX) were selected as reductase partners. Glucose dehydrogenase system has been selected as the NADH regenerating system with catalase being used to consume H2O2.
3) Engineering of Candida viswanathii ATCC 20962 towards mid to long-chain alkane to diacid (DCA) conversion have been established and parameterized. 14 bacterial strains towards mid to long-chain alkane to diol conversion were genetically engineered. Two mutant strains of P. fluorescens SBW25 and two mutant strains of P. putida KTT240 showed most promising diol synthesis.
4) Chemical polymerization for the bulk synthesis of polyesters were conducted by mixing various aliphatic diols and diacids (of different chain lengths) . A screening of various catalysts showed that Titanium (IV) butoxide (Ti(Bu)4) was the best catalytic systems. Novel biobased short-chain diols, along with long-chain length biobased diacids were used to produce aliphatic polyester under melt conditions mediated by lipase-catalyzed polycondensation. The synthesized polyesters were characterized using a plethora of analytical techniques for 1H NMR, WAXD, TGA and DSC.
5) Life Cycle Assessments (LCA) has been initiated according to international standards ISO 14044 and ISO 14040. LCA is proceeded in 4 phases: Objective, scope and boundary of the system, Life Cycle Inventory (LCI), life cycle impact assessment and interpretation of the results. An excel template for the LCI has been developed, and assigned to the researchers of each WP to collect the necessary information to elaborate a quality LCI, and intermediate LCA study (lab scale data).
1) Two catalytic systems (Ru/TiH2 and CeO2-promoted Pt/zeolite) were developed and tested. Hydrogenolysis of LDPE over Ru/TiH2 achieved ~75% PE conversion and ~37% selectivity toward the C6–C18 fraction. Hydrocracking of LDPE over Pt/zeolite achieved complete PE conversion and ~15% selectivity toward the C6–C18 fraction.
2) 6 different CYP153 monooxygenase orthologs were screened, and CYP153A33 and CYP153A71 demonstrated highest diol and diacid production, towards C6-C12 range of alkanes. As for auxiliary enzymes, Putidaredoxin reductase (PdR) and putidaredoxin (PdX) were selected as reductase partners. Glucose dehydrogenase system has been selected as the NADH regenerating system with catalase being used to consume H2O2.
3) Engineering of Candida viswanathii ATCC 20962 towards mid to long-chain alkane to diacid (DCA) conversion have been established and parameterized. 14 bacterial strains towards mid to long-chain alkane to diol conversion were genetically engineered. Two mutant strains of P. fluorescens SBW25 and two mutant strains of P. putida KTT240 showed most promising diol synthesis.
4) Chemical polymerization for the bulk synthesis of polyesters were conducted by mixing various aliphatic diols and diacids (of different chain lengths) . A screening of various catalysts showed that Titanium (IV) butoxide (Ti(Bu)4) was the best catalytic systems. Novel biobased short-chain diols, along with long-chain length biobased diacids were used to produce aliphatic polyester under melt conditions mediated by lipase-catalyzed polycondensation. The synthesized polyesters were characterized using a plethora of analytical techniques for 1H NMR, WAXD, TGA and DSC.
5) Life Cycle Assessments (LCA) has been initiated according to international standards ISO 14044 and ISO 14040. LCA is proceeded in 4 phases: Objective, scope and boundary of the system, Life Cycle Inventory (LCI), life cycle impact assessment and interpretation of the results. An excel template for the LCI has been developed, and assigned to the researchers of each WP to collect the necessary information to elaborate a quality LCI, and intermediate LCA study (lab scale data).
In this report period, the key results beyond the state-of-the art achieved by the ACTPAC and the key needs to ensure further uptake and success, include
1) Primary proof-of-concept phenotypes of hydrocracking catalysts for cleavage of PE into liquid alkanes is established --> Needs to improve the conversion, yield and selectivity towards C6-C18, and reduce operation temperature and pressure.
2) 1st generation of genotype of enzyme systems for transformation of short-to-medium alkanes into diols/ diacids is identified --> Needs to improve the conversion, yield and selectivity towards diols or diacids by enzyme engineering.
3) The primary genotypes of microbial alkane-converting system are identified --> Needs to further identify and incorporate more effective genes in the yeast/bacteria for diols synthesis.
4) Primary proof-of-concept phenotypes of chemical and enzymatic polymerization systems are established --> Needs to identify more effective catalysts and enzyme variants, optimize operation variables, and specify their applications to PE-derived monomers to yield new polyesters.
To date, for all technical objectives further research are ongoing and the exploitable results are still developing. With the project progress, an exploitation strategy, including innovativeness, benefits, target users, TRL level and requirements, will be developed, and the exploitation actions including analysis of market trends, existing patents, competitors, IPR and a SWOT analysis as well as the associated timeline will be made.
1) Primary proof-of-concept phenotypes of hydrocracking catalysts for cleavage of PE into liquid alkanes is established --> Needs to improve the conversion, yield and selectivity towards C6-C18, and reduce operation temperature and pressure.
2) 1st generation of genotype of enzyme systems for transformation of short-to-medium alkanes into diols/ diacids is identified --> Needs to improve the conversion, yield and selectivity towards diols or diacids by enzyme engineering.
3) The primary genotypes of microbial alkane-converting system are identified --> Needs to further identify and incorporate more effective genes in the yeast/bacteria for diols synthesis.
4) Primary proof-of-concept phenotypes of chemical and enzymatic polymerization systems are established --> Needs to identify more effective catalysts and enzyme variants, optimize operation variables, and specify their applications to PE-derived monomers to yield new polyesters.
To date, for all technical objectives further research are ongoing and the exploitable results are still developing. With the project progress, an exploitation strategy, including innovativeness, benefits, target users, TRL level and requirements, will be developed, and the exploitation actions including analysis of market trends, existing patents, competitors, IPR and a SWOT analysis as well as the associated timeline will be made.