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Microbial composition and polymer hydrolytic activity of Japanese washed-rind cheeses

Tachibana, Yohko, Kageyama, Kohei, Suzuki, Miwa, Koshigumo, Hitomi, Takeno, Hiroyuki, Tachibana, Yuya, Kasuya, Ken-ichi
Polymer degradation and stability 2019 v.160 pp. 264-272
Alcanivorax dieselolei, aquatic bacteria, biodegradability, cheeses, fermented foods, food packaging, fungi, metagenomics, packaging materials, phenotype, phylogeny, polymers, temperature
Since the use of biodegradable polymers for food packaging is becoming popular, it is important to investigate the biodegradable-polymer-hydrolyzing potential of microorganisms in fermented foods. Here, we focused on 4 Japanese washed-rind cheeses. Metagenomic analyses revealed that microbiota in the 4 Japanese washed-rind cheeses was composed of bacteria classified into 515 operational taxonomic units (OTUs) and fungi classified into 74 OTUs. Remarkably, a considerable number of marine bacteria were identified in 3 of 4 cheeses. Further, we isolated a poly(3-hydroxybutyrate) (P(3HB))-degrading bacterium, designated as strain MC1, from one of the cheeses—Muchuri. The strain was a gram-negative, rod-shaped bacterium. It grew well and formed a large clear zone on P(3HB)-containing medium at a temperature range of 30–37 °C, while it did not degrade P(3HB) at 4 °C. The phenotypic properties and phylogenetic inference indicated that strain MC1 is related to Alcanivorax dieselolei B-5T, which is a marine inhabitant. Our study demonstrated that MC1 degrades P(3HB) and that components in cheese promote the degradation of P(3HB) while nutrient-rich conditions suppress it. This suggests that packaging material made of P(3HB) for cheeses could be used under low temperatures and nutrient-rich conditions.