Screening and Characterization of New Acetobacter fabarum and Acetobacter pasteurianus Strains with High Ethanol−Thermo Tolerance and the Optimization of Acetic Acid Production.

The production of vinegar on an industrial scale from different raw materials is subject to constraints, notably the low tolerance of acetic acid bacteria (AAB) to high temperatures and high ethanol concentrations. In this study, we used 25 samples of different fruits from seven Moroccan biotopes with arid and semi-arid environmental conditions as a basic substrate to isolate thermo- and ethanol-tolerant AAB strains. The isolation and morphological, biochemical and metabolic characterization of these bacteria allowed us to isolate a total number of 400 strains with characters similar to AAB, of which six strains (FAGD1, FAGD10, FAGD18 and GCM2, GCM4, GCM15) were found to be mobile and immobile Gram-negative bacteria with ellipsoidal rod-shaped colonies that clustered in pairs and in isolated chains.

Screening and molecular characterization of new thermo- and ethanol-tolerant Acetobacter malorum strains isolated from two biomes Moroccan cactus fruits.

Industrially, the sensitivity of acetic acid bacteria (AAB) to the high temperatures and the high ethanol concentrations is the major concerns for manufacturers. This study was conceived and designed to isolate and identify new thermo- and ethanol-tolerant AAB from Opuntia ficus-indica L. fruits.