Publications by authors named "Motonori Yamamoto"

Environmentally friendly functionalization and recycling processes for synthetic polymers have recently gained momentum, and enzymes play a central role in these procedures. However, natural enzymes must be engineered to accept synthetic polymers as substrates. To enhance the activity on synthetic polyesters, the canonical amino acid methionine in lipase (TTL) was exchanged by the residue-specific incorporation method for the more hydrophobic non-canonical norleucine (Nle).

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Synthetic polyesters are today the second-largest class of ingredients in household products and are entering wastewater treatment plants (WWTPs) after product utilization. One approach to improve polymer biodegradation in wastewater would be to complement current processes with polyester-hydrolyzing enzymes and their microbial producers. In this study, the hydrolysis of poly(oxyethylene terephthalate) polymer by hydrolases from wastewater microorganisms was investigated in vitro and under realistic WWTP conditions.

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A series of copolyesters based on furanic acid and sulfonated isophthalic acid with various polyols were synthetized and their susceptibility to enzymatic hydrolysis by cutinase 1 from (Thc_Cut1) investigated. All copolyesters consisted of 30 mol % 5-sulfoisophthalate units (NaSIP) and 70 mol % 2,5-furandicarboxylic acid (FDCA), while the polyol component was varied, including 1,2-ethanediol, 1,4-butanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, or tetraethylene glycol. The composition of the copolyesters was confirmed by ¹H-NMR and the number average molecular weight (M) was determined by GPC to range from 2630 to 8030 g/mol.

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Polyesters of 2,5-furandicarboxylic acid (FDCA) have gained attention as they can be regarded as the bio-based alternatives to the petroleum-based polyesters of terephthalic acid. However, only little is known about the biodegradation and enzymatic hydrolysis of FDCA-based polyesters. This work aims to investigate the influence of different polyols on enzymatic hydrolysis of FDCA-based polyesters.

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Water-soluble polyesters are used in a range of applications today and enter wastewater treatment plants after product utilization. However, little is known about extracellular enzymes and aquatic microorganisms involved in polyester biodegradation and mineralization. In this study, structurally different ionic phthalic acid based polyesters (the number-average molecular weights (M) 1770 to 10 000 g/mol and semi crystalline with crystallinity below 1%) were synthesized in various combinations.

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Extracellular enzymes are assumed to be responsible for the initial and rate limiting step in biodegradation of polymers. Mainly enzymes with aliphatic esters as their natural substrates (e.g.

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Polyamides are important industrial polymers. Currently, they are produced exclusively from petrochemical monomers. Herein, we report the production of a novel bio-nylon, PA5.

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It is completely plausible that unmodified materials of natural origin, such as the native macromolecules cellulose or starch, are biodegradable. If these materials are modified then degradation may, depending on the degree of modification, be more difficult or even impossible. In the same manner synthesized macromolecules, whether from renewable or petrochemical sources, could be inert or completey biodegradable, depending on their chemical structure.

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