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Y Shigeno-Akutsu

Publications and source records attributed to Y Shigeno-Akutsu.

5 recordsLinked to original sources
PubMed2003

Isolation and characterization of a bacterium that degrades various polyester-based biodegradable plastics.

Microorganisms isolated from soil samples were screened for their ability to degrade various biodegradable polyester-based plastics. The most active strain, designated as strain TB-13, was selected as the best strain for degrading these plastics. From its phenotypic and genetic characteristics, strain TB-13 was closely related to Paenibacillus amyloyticus. It could degrade poly(lactic acid), poly(butylene succinate), poly(butylene succinate-co-adipate), poly(caprolactone) and poly(ethylene succinate) but not poly(hydroxybutylate-co-valerate). However, it could not utilize these plastics as sole carbon sources. Both protease and esterase activities, which may be involved in the degradation of plastic, were constitutively detected in the culture broth.

Adipates↗
PubMed2000

Properties of a bacterium which degrades solid poly(tetramethylene succinate)-co-adipate, a biodegradable plastic.

Various microorganisms were screened for their ability to degrade poly(tetramethylene succinate)-co-(tetramethylene adipate) (PBSA). Strain BS-3, which was newly isolated from a soil sample, was selected as the best strain. From taxonomical studies, the strain was tentatively ascribed to belong to the genus Acidovorax, most probably to the species A. delafieldii. Strain BS-3 could degrade both solid and emulsified PBSA, and also emulsified poly(tetramethylene succinate). During the degradation, a lipase activity was observed in the culture broth. This lipase activity was induced more strongly by PBSA than by tributyrin or triolein which are typical substrates of lipase. These observations strongly suggest that this lipase was involved in the PBSA biodegradation in strain BS-3.

Adipates↗
PubMed1999

Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes.

Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.

Bacteria↗
PubMed1999

Purification and properties of culture-broth-secreted esterase from the polyurethane degrader Comamonas acidovorans TB-35.

The polyester-polyurethane (PUR)-degrading bacterium Comamonas acidovorans TB-35 produces two kinds of esterases, one cell-bound esterase (PUR esterase) and the other secreted in the culture broth (CBS esterase). In this study, the CBS esterase and the two recombinant esterases were purified. Identification of the physical and biochemical properties of the CBS and PUR esterases revealed that they have the same polypeptide from one gene. This finding was supported by the observation that Escherichia coli harboring the PUR esterase gene also produced two kinds of esterases. Though the PUR esterase degraded PUR and poly(diethylene glycol adipate), the soft segment of the PUR, the CBS esterase degraded only poly(diethylene glycol adipate). Furthermore, the hydrophobicity of the CBS esterase was lower than that of the PUR esterase. As the PUR esterase has been previously indicated to possess a PUR-binding domain, it was assumed that structural change around the PUR-binding domain of the CBS esterase was responsible for its inability to degrade PUR.

Journal Article↗