Acinetobacter harbinensis sp. nov., isolated from river water

Area of Science:

• Microbiology
• Bacteriology
• Environmental Science

Background:

• Nitrifying bacteria play a crucial role in aquatic ecosystems.
• Isolation of novel bacterial species aids in understanding microbial diversity and function.
• The Songhua River is a significant freshwater ecosystem in China.

Purpose of the Study:

• To isolate and characterize a novel nitrifying bacterial strain from the Songhua River.
• To determine the taxonomic position of the isolate using genotypic, phenotypic, and chemotaxonomic analyses.
• To propose a new species within the genus Acinetobacter.

Main Methods:

• Isolation of bacteria from river surface water.
• Cultivation in mineral media with acetate and ammonia.
• Gram staining, oxidase testing, motility assessment.
• Growth temperature range determination.
• DNA G+C content determination.
• 16S rRNA, rpoB, and gyrB gene sequencing.
• Cellular fatty acid analysis.
• Biochemical tests (acid production, gelatin hydrolysis).

Main Results:

• A Gram-negative, aerobic, non-motile coccobacillus (HITLi 7T) was isolated.
• The isolate grew at 2 °C but not at 37 °C.
• 16S rRNA gene sequence analysis showed 98.4% similarity to Acinetobacter lwoffii.
• rpoB and gyrB gene sequences did not show significant similarity to other Acinetobacter species.
• Predominant fatty acids were 9-octadecenoic acid and summed feature 4.
• Acid was not produced from d-glucose, and gelatin was not hydrolyzed.
• DNA G+C content was 45.5 mol%.

Conclusions:

• The genotypic, phenotypic, and chemotaxonomic data support the classification of HITLi 7T as a novel species.
• The proposed name for the new species is Acinetobacter harbinensis sp. nov.
• The type strain is HITLi 7T (=CGMCC 1.12528T=KCTC 32411T).