20.500.12556/RUL-176203 Gluconacetobacter brunescens sp. nov., a novel acetic acid bacterium isolated from pear vinegar, producing a water-soluble brown pigment The clade Gluconacetobacter comprises eleven species originating from various sources such as rhizosphere soil, pink sugarcane mealybug, and vinegar. During sampling of organic vinegars, we isolated strain Hr-1-5, which exhibits high 16S rRNA gene sequence identities (≤98.6%) and low 16S-23S rRNA gene internal transcribed spacer (ITS) sequence identities (≤92.1%) with Gluconacetobacter species. Further genome analysis confirmed that strain Hr-1-5 is a distinct species, supported by an average nucleotide identity (ANIb) of ≤90.6% and an in silico DNA–DNA hybridization (dDDH) value of ≤46% compared with other recognized Gluconacetobacter species. Strain Hr-1-5 darkens the growth medium to a deep brown after 4–5 days of submerged cultivation and similarly colors agar medium after 5–6 days. In silico genome analysis suggests that the strain synthesizes pyomelanin. Phenotypically, it is distinguished from its closest Gluconacetobacter relatives by its ability to produce 5-keto-D-gluconic acid, but not 2-keto-D-gluconic acid, and by its capacity to grow on D-ribose, among other traits. These findings support the classification of strain Hr-1-5 as a novel species, for which we propose the name Gluconacetobacter brunescens sp. nov. Hr-1-5T (=ZIM B1168T = LMG 33629T ). Strain Hr-1-5 is of biotechnological interest for its pigment production and enables the in situ production of colored cellulose in a co-culture with a cellulose-producing acetic acid bacterium. acetic acid bacteria Acetobacteraceae Gluconacetobacter Gluconacetobacter brunescens pear vinegar natural pigments melanin ocetnokislinske bakterije hruškov kis mikrobne združbe pigmenti true false true Angleški jezik Slovenski jezik Članek v reviji 2025-11-25 09:09:35 2025-11-25 09:09:40 2025-12-19 03:50:56 0000-00-00 00:00:00 2025 0 0 20 str. iss. 11, art. 2620 Vol. 13 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 579.67 2076-2607 10.3390/microorganisms13112620 257905667 karnicnik_et_al__G_brunescens_2025.pdf karnicnik_et_al__G_brunescens_2025.pdf 1 F9A07E34DF7BE0A09E70CCC1FEF9ACB6 ee5dba69c34869553768da672bbb8db8183ed3929447c5e52f2eda3640d6586d 629092bd-c9d6-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=222465 https://www.mdpi.com/2076-2607/13/11/2620 1 bb8cf16a-c9d5-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=222464 Biotehniška fakulteta 0 0 0