Biochemical reaction Result Nitrate + Growth in MacConkey + Urea hydrolysis +
Esculin hydrolysis + Gelatin hydrolysis - ONPG (o-nitrophenyl-[beta]-D-galactopyranoside) + Oxidase + Vogesproskauer - [beta]-Galactosidase - Tryptophan deaminase - Ornithine decarboxylase - Lysine decarboxylase - Arginine decarboxylase - Motility + Glucose (assimilation) + Mannose + Mannitol + Maltose + Gluconate + Arabinose + Adonitol + Glutamyl arylamidase pNA + Indole -
To determine the biotype of isolates,
esculin, indole, and lipase activity were investigated.
Esculin, or sculin, is a chemical that naturally occurs in the horse chestnut, a plant extract.
The selected LAB strains were assessed for the shape, cell wall composition (Gram staining), catalase production, carbohydrate, and sugar fermentation (amygdalin, arabinose, cellobiose,
esculin, fructose, galactose, glucose, lactose, maltose, mannitol, raffinose, rhamnose, ribose, sorbitol, sucrose, and trehalose) as described in the Bergey's Manual of Determinative Bacteriology.
Anaerobic culture yielded irregular, grey, non-hemolytic, molar tooth colonies of Gram-positive bacilli, negative for catalase, urease, and indole tests but positive for
esculin hydrolysis test, identified as A.
Entero-set consisting of growth on
esculin agar in the presence of 40% bile, 6.5% NaCl, and arabinose test was used to identify Enterococci.
Like Enterococci it may reproduce in 6.5% NaCl and hydrolysis
esculin in the presence of bile.
Further, the bacterial isolate decarboxylated arginine but did not decarboxylate lysine and ornithine and hydrolysed gelatin but did not hydrolyse
esculin. It did not produce urease, indole, and DNase.
Mean content (mg/100 ml) Molecule Alcohol- Ale free 2,3-Dihydroxy-1-guaiacylpropanone 0.0025 3-Methylcatechol 4-Ethylcatechol 4-Hydroxycoumarin 4-Methylcatechol 4-Vinylguaiacol 0.0100 4-Vinylphenol Catechol
Esculin Pyrogallol Tyrosol 0.2700 Umbelliferone Vanillin 0.0048 Mean content (mg/100 ml) Molecule Dark Regular 2,3-Dihydroxy-1-guaiacylpropanone 0.0034 3-Methylcatechol 0.0029 0.0001 4-Ethylcatechol 0.0010 0.0006 4-Hydroxycoumarin 0.1100 4-Methylcatechol 0.0022 4-Vinylguaiacol 0.0300 0.1500 4-Vinylphenol 0.0300 0.0045 Catechol 0.0100 0.0011
Esculin 0.0200 Pyrogallol 0.0300 0.0047 Tyrosol 0.3200 Umbelliferone 0.0017 Vanillin 0.0200 Data from the Phenol-Explorer database [12].
Esculetin,
esculin, fraxin, and fraxetin are some of the pharmacologically active components isolated from different species of Fraxinus plant (Figure 2).
Dextran production on MSE medium [22], citric acid degradation on Kempler and McKay solid medium,
esculin hydrolysis and production of acetoine on Clark and Lubs medium [23,24].