Bio-upcycling of polyethylene terephthalate
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Cites background from "Bio-upcycling of polyethylene terep..."
...Perhaps these strains could serve as useful sources of TPA catabolic genes for synthetic biology efforts associated with biological plastics recycling and upcycling (67)....
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Cites methods from "Bio-upcycling of polyethylene terep..."
...Samples from both time zero and the endpoints are grown under selective conditions, after which their gDNA is extracted (2), barcodes are amplified from conserved priming sites (3), barcode abundance is calculated via Illumina sequencing (4), and gene fitness per condition is calculated by comparing the relative abundances of mutants before and after selection (5)....
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Frequently Asked Questions (15)
Q2. What are the future works mentioned in the paper "Bio-upcycling of polyethylene terephthalate" ?
Currently further metagenome and mechanistic studies of this important enzyme class are carried out by the scientific community, most likely discovering protein family members with superb activities or at least interesting amino acid variations. Accessing non-biodegradable plastics of petrochemical origin ( and in the future of biological origin ) as carbon source for fermentations enables biotechnology to valorize enormous waste streams for the sustainable production of many valuable products by exploiting the metabolic versatility of microorganisms. While the mesophilic PET hydrolase from I. sakaiensis15 suggests consolidated hydrolysis and utilization, the authors focused on sequential plastic depolymerization and monomer conversion on purpose.
Q3. What is the potential of enzyme cocktails?
The use of enzyme cocktails will also enable feedstock flexibility, especially when combined with microbes engineered to accept other plastic-derived substrates.
Q4. What is the synthesis of a poly(amide urethane)?
Since an isocyanate moiety can react with both an hydroxyl and a carboxylic acid group, and HAA is an hydroxy acid, its direct polymerization with 4,4’- methylene diphenyl diisocyanate (MDI) and butanediol (BDO) was performed and led to the formation of a poly(amide urethane).
Q5. How did the thermal stability of the polymer change?
The polymer started to degrade and to lose volatile products at 160 °C and then showed a multi-step degradation profile with the main mass loss occurring between 250 and 350 °C.
Q6. How many plastics are currently being used in the packaging industry?
Renewable plastics including PHA have already been proposed to effectuate a shift of the packaging industry, which consumes over 38% of the plastics produced53.
Q7. What is the important advantage of lignocellulose-derived substrates?
Lignocellulose-derived substrates come with a large fraction of solids, which are not completely degraded impeding the application of, e.g., enzyme immobilization or in situ removal of formed monomers (by e.g., precipitation or extraction).
Q8. What is the main reason for the lack of recycling of plastic?
While plastic, due to its lightweight and sturdiness, has many environmentally beneficial applications, the environmental damage caused by plastic must be arrested by addressing the end-of-life challenge.
Q9. How many ml samples were taken for each time point?
Three 2 ml samples were taken at regular intervals for the analysis of TA, EG and nitrogen concentrations, biomass, and PHA accumulation for each time point.
Q10. What is the way to increase plastic recycling?
An alternative way to increase plastic recycling is to add additional value to the plastic waste, not aiming for the same material or consumer good (e.g., bottle-to-bottle recycling), but rather upcycling to chemicals and materials of higher value.
Q11. What is the way to degrade PET?
The use of enzyme engineering and enzyme cocktail formulation will enable an even more efficient PET degradation, for instance using specialized enzymes of the various types of PET, i.e. high molecular weight PET and PET oligomers mono-(2-hydroxyethyl)TA (MHET) and bis2(hydroxyethyl)TA (BHET); possibly combined with chemical hydrolysis methods such as glycolysis56.
Q12. How much of the TA and EG concentrations increased during the hydrolysis?
The concentration of TA and EG showed a steep near-linear increase within the first 24 h of the hydrolytic reaction and weakened to a markedly lower rate until 120 h.
Q13. Who supervised the experiments regarding monomer metabolism and synthesis?
TT supervised the experiments regarding monomer metabolism and HAA synthesis, drafted the manuscript, and coordinated the study, TN provided strain Pseudomonas sp. GO16, supervised the experiments regarding PHA synthesis and drafted parts of the manuscript, RW supervised the experiments regarding depolymerization and drafted parts of the manuscript, EP supervised the experiments regarding polymerization and drafted parts of the manuscript, KS carried out the experiments regarding monomer metabolism and HAA synthesis, NB carried out the experiments regarding PHA synthesis, AH carried out the experiments regarding depolymerization, MJ carried out the experiments regarding polymerization, SK was involved in PHA bioprocess design, NW was involved in designing and coordinating the study, drafted parts of the manuscript and critically read the manuscript, RP was involved in designing the study and critically read the manuscript, LA was involved in designing the study and critically read the manuscript, WZ was involved in designing the study and critically read the manuscript, KOC designed the study and critically read the manuscript, LMB designed and coordinated the study and critically read the manuscript.
Q14. What is the main reason for the biodegradation of plastic waste?
For obvious reasons, the biodegradation of these recalcitrant plastics are exciting discoveries that give hope for the natural bioremediation of sites contaminated with plastic waste in the environment, although plastic degradation in the ocean seems to be slow at best and the anthropogenic dissemination of new plastic pollution likely far exceeds its decay18.
Q15. How many tons of plastics were produced in 2018?
In 2018, 359 million tons of plastics have been produced worldwide and this number is growing at a rate of approximately 3% per annum1.