title: Isolation from a shea cake digester of a tannin-tolerant Escherichia coli strain decarboxylating p-hydroxybenzoic and vanillic acids.
abstract: A facultatively anaerobic, mesophilic, Gram-negative, non-motile, non-sporulated bacterium, designated strain C2, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds and previously inoculated with anaerobic sludge from the pit of a slaughterhouse, after enrichment on tannic acid. The straight rods occurred singly or in pairs. Strain C2 fermented numerous carbohydrates (fructose, galactose, glucose, lactose, mannose, maltose, melibiose, raffinose, rhamnose, ribose, saccharose, sorbitol, trehalose, and xylose) and peptides (Biotrypcase, Casamino acids, and yeast extract), producing acid and gas, and had a G + C content of 51.6 +/- 0.1 mol %. Strain C2 was very closely related to Escherichia coli (= DSM 30083(T)) phylogenetically (similarity of 99%), genotypically (DNA homology of 79%), and phenotypically. The isolate tolerated tannic acid (hydrolyzable tannin) and decarboxylated by non-oxidative decarboxylation only p-hydroxybenzoic and vanillic acids to their corresponding phenol and guaicol, under anaerobic and aerobic conditions without further degradation. Adding glucose increased growth and the rate of conversion. High concentrations of p-hydroxybenzoic acid or vanillic acid inhibited growth, and decarboxylation could not occur completely, suggesting phenol toxicity. In contrast, the type strain of E. coli cannot metabolize p-hydroxybenzoic and vanillic acids, anaerobically or aerobically, with or without glucose added.
authors.affiliation: Laboratoire de Microbiologie IRD,IFR-BAIM, Universités de Provence et de la Méditerranée, ESIL case 925, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Chamkha
authors.forename: Eric
authors.initials: E
authors.lastname: Record
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Garcia
authors.forename: Marcel
authors.initials: M
authors.lastname: Asther
authors.forename: Marc
authors.initials: M
authors.lastname: Labat
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D019149:Bioreactors; D003470:Culture Media; D003653:Decarboxylation; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism*; D006139:Guaiacol / Q000378:metabolism; D047348:Hydrolyzable Tannins / Q000378:metabolism*; D008956:Models, Chemical; D010226:Parabens / Q000737:chemistry / Q000378:metabolism*; D019800:Phenol / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014197:Trees / Q000382:microbiology; D014641:Vanillic Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003470:Culture Media; D047348:Hydrolyzable Tannins; D010226:Parabens; D012336:RNA, Ribosomal, 16S; D019800:Phenol; D006139:Guaiacol; D014641:Vanillic Acid; C038193:4-hydroxybenzoic acid