The influence of cultivation conditions on the immobilized acetic acid bacteria metabolic activity

Brewing is an innovative sector of the food industry. Non-alcoholic beer production increases every year. The largest volumes of non-alcoholic beer are obtained by regular beer dialysis. The beer dialysate formed in production contains ethyl alcohol, which entails the need for its rational use. One of the effective ways to use beer dialysate is food biochemical vinegar production. The purpose of the work is to conduct research for biotechnology development of food vinegar from beer dialysates generation using acetic acid bacteria (AAB) immobilization on bio-carriers of various nature. The objects of research were samples of beer dialysates (BD), concentrated to a volume fraction of ethyl alcohol of 7.5%, Acetobacter aceti AAB, vinegar from BD. To study the changes in metabolic activity of immobilized AAB on a bio-carrier, acetic acid fermentation was performed using Acetobacter aceti cells, immobilized on beech shavings, zeolite, and high-pressure polyethylene. Air was supplied to a reservoir by a microcompressor from below through a finely porous ceramic nozzle, providing uniform air dispersion in cultural fluid. Graphs of the cells number and Acetobacter aceti biomass dependence on cultivation duration, nature of the bio-carrier and the aeration method when obtaining vinegar from beer dialysate are presented. The experimental data of the volatile components composition, organic acids and beer dialysate amino acids and vinegar from it are presented. Electron microscopic research of Acetobacter aceti AAB during beech shavings and zeolite cultivation is presented. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are presented.