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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is a strong need for novel and more efficient polyester hydrolyzing enzymes in order to enable the development of more environmentally friendly plastics recycling processes allowing the closure of the carbon cycle. In this work, a high throughput system on microplate scale was used to screen a high number of fungi for their ability to produce polyester-hydrolyzing enzymes. For induction of responsible enzymes, the fungi were cultivated in presence of aliphatic and aromatic polyesters [poly(1,4-butylene adipate co terephthalate) (PBAT), poly(lactic acid) (PLA) and poly(1,4-butylene succinate) (PBS)], and the esterase activity in the culture supernatants was compared to the culture supernatants of fungi grown without polymers. The results indicate that the esterase activity of the culture supernatants was induced in about 10% of the tested fungi when grown with polyesters in the medium, as indicated by increased activity (to >50 mU/mL) toward the small model substrate para-nitrophenylbutyrate (pNPB). Incubation of these 50 active culture supernatants with different polyesters (PBAT, PLA, PBS) led to hydrolysis of at least one of the polymers according to liquid chromatography-based quantification of the hydrolysis products terephthalic acid, lactic acid and succinic acid, respectively. Interestingly, the specificities for the investigated polyesters varied among the supernatants of the different fungi.
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PMID:High Throughput Screening for New Fungal Polyester Hydrolyzing Enzymes. 3239 Sep 56

Plasticized poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) blend-based films containing chitin nanofibrils (CN) and calcium carbonate were prepared by extrusion and compression molding. On the basis of previous studies, processability was controlled by the use of a few percent of a commercial acrylic copolymer acting as melt strength enhancer and calcium carbonate. Furthermore, acetyl n-tributyl citrate (ATBC), a renewable and biodegradable plasticizer (notoriously adopted in PLA based products) was added to facilitate not only the processability but also to increase the mechanical flexibility and toughness. However, during the storage of these films, a partial loss of plasticizer was observed. The consequence of this is not only correlated to the change of the mechanical properties making the films more rigid but also to the crystallization and development of surficial oiliness. The effect of the addition of calcium carbonate (nanometric and micrometric) and natural nanofibers (chitin nanofibrils) to reduce/control the plasticizer migration was investigated. The prediction of plasticizer migration from the films' core to the external surface was carried out and the diffusion coefficients, obtained by regression of the experimental migration data plotted as the square root of time, were evaluated for different blends compositions. The results of the diffusion coefficients, obtained thanks to migration tests, showed that the CN can slow the plasticizer migration. However, the best result was achieved with micrometric calcium carbonate while nanometric calcium carbonate results were less effective due to favoring of some bio polyesters' chain scission. The use of both micrometric calcium carbonate and CN was counterproductive due to the agglomeration phenomena that were observed.
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PMID:Sustainable Micro and Nano Additives for Controlling the Migration of a Biobased Plasticizer from PLA-Based Flexible Films. 3256 May 20

Soil microplastic pollution has caused widespread research attention worldwide. It is necessary to efficiently separate microplastic particles from soil matrixes in order to conduct studies of microplastic. And so far, few studies have described the separation and extraction devices of biodegradable microplastic. Here we present a commonly available device for extraction of non-degradable and biodegradable microplastics from soil samples in a NaBr solution based on density flotation. The device has a combined circulation and recovery system for the salt solution, which increases its environmental-friendliness. The accuracy and precision of the device was verified through spike and recovery experiments using three types of biodegradable microplastics (PBS, PBAT, PLA) and four types of non-degradable microplastics (LDPE, PS, PP, PVC), all with different particle sizes, and all microplastics are grinded autonomously, closer to reality. In despite of differences in particle size and density, for both biodegradable and non-degradable microplastics the device exhibited good extraction precision, with recovery rates ranging from 92% to 99.6%, over a wide range of particle densities and sizes. The recovery rates slightly increased with increased polymer density and microplastic particle size.
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PMID:A commonly available and easily assembled device for extraction of bio/non-degradable microplastics from soil by flotation in NaBr solution. 3326 78


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