Acetic Acid Bacteria: Physiology and Carbon Sources Oxidation

Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called “oxidative fermentations”, especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism

Donghicola mangrovi sp. nov., a member of the family Rhodobacteraceae isolated from mangrove forest in Thailand

Two novel Gram-stain-negative, rod-shaped and non-motile bacterial strains, designated B5-SW-15T and C2-DW-16, were isolated from water collected in mangrove forests in Ranong Province, Thailand. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains B5-SW-15T and C2-DW-16 belonged to the genus Donghicola and were most closely related to Donghicola tyrosinivorans DSM 100212T (98.2 and 98.1 %, respectively) and Donghicola eburneus DSM 29127T (97.7 and 97.6 %, respectively). The average nucleotide identity and digital DNA-DNA hybridization values between strain B5-SW-15T, strain C2-DW-16 and related species were 95.8 and 71.6 % (to strain C2-DW-16), 76.8 and 21.3 % (to D. tyrosinivorans DSM 100212T) and 80.3 and 24.2 % (to D. eburneus DSM 29127T), respectively. The predominant cellular fatty acids (>5 %) were summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c), C16 : 0 and C12 : 1 3-OH. Ubiquinone Q-10 was the sole respiratory quinone. DNA G+C contents of the isolates were 61.0 and 61.2 mol% based on whole genome sequences. Strains B5-SW-15T and C2-DW-16 contained aminolipid, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. On the basis of the results from phenotypic, chemotaxonomic and phylogenetic analyses, strains B5-SW-15T and C2-DW-16 constitute a novel species of the genus Donghicola in the family Rhodobacteraceae for which the name Donghicola mangrovi sp. nov. is proposed. The type strain is B5-SW-15T (=BCC 56522T=TBRC 9562T=KCTC 72743T).