Comparison of enzymatic properties of production strains of microorganisms used in the bakery industry with those of reference strains

Abstract

The article deals with the results of the comparative analysis of the enzymatic properties of the production strains of Saccharomyces cerevisiae, Candida milleri and Lactobacillus plantarum,which were isolated from the ferment used in the production facilities of the Kiev region with the properties of the reference strains purchased in the Russian Federation. There were investigated the properties of two production strains of Saccharomyces cerevisiae and Candida milleri and one strain of Lactobacillus plantarum. The isolation of the production strains was carried out by generally accepted methods in microbiology, and their identification was carried out on the basis of the results of the investigation of morphological features and cultural and enzymatic properties according to the determinant of bacteria Burge (1997). The biochemical properties of the bacteria were studied by the indicators of their relation to oxygen, the ability to break down carbohydrates with the accumulation of certain products of metabolism. To determine the ability to ferment carbohydrates and alcohols used short and long “colored” series of Giss. The short series included environments with glucose, lactose, sucrose, maltose and mannitol, and in the long – additionally introduced environments with arabinose, xylose, rhamnose, galactose, as well as inulin, starch, dextrin and glycerol, dulcite and inositol. The incubation was carried out in a thermostat at a temperature of 30 ± 1 °C, and the results were evaluated in 2–4 days, taking into account the change whether there is no change in the color of the indicator and the environment, the appearance or absence of gas in the float, etc. Proteolytic activity was investigated for the ability of microorganisms to dilute gelatin and peptone milk, catalase – by interaction with a 10% solution of hydrogen peroxide, the ability to synthesize indole – Morel method, and ammonia and hydrogen by changing the color of the strip of litmus paper impregnated with the Andrade reagent and lead acetate solution, respectively. It is installed, that the Saccharomyces cerevisiae production strains used at the production facilities of the Kyiv region, as well as the reference strain purchased from the Russian Federation, they fermented glucose, galactose, sucrose, maltose, trehalose, melibiosis, raffinose, melecitosis and ethanol and did not ferment cellobiose, rhamnose, lactose and insulin. However, unlike the reference strains, the production strains did not have the ability to ferment xylose. Candida milleri strains, unlike Saccharomyces cerevisiae strains, do not have the ability to ferment maltose and, unlike reference strains, their production strains do not ferment xylose. The searches have found no differences in the enzymatic properties of the reference and production strain of Lactobacillus plantarum. Both microorganisms fermented glucose, galactose, sucrose, maltose, lactose, raffinose, mannitol and did not ferment rhamnose, arabinose and xylose. Based on the results of microbiological searches of production strains of Lactobacillus plantarum, Lactobacillus fermenti, Saccharomyces cerevisiae and Candida milleri, in particular the search of their enzymatic properties by means of the standardized colorimetric identification system KB009 TM HiCarburgate Kit, at the Ukrainian Laboratory of Quality and Product Safety at the AIC of the National University of Bioresources and nature management of Ukraine were certified the following strains: Lactobacillus plantarum LPR-2018/5; Lactobacillus fermenti LLF-2018/5, Saccharomyces cerevisiae SLC-2017/5, Candida milleri CLM-2017/7.