Prospects of Using by-Products of Potato Starch Production as Components of Growth Media for Lactic Acid Bacteria Cultivation

Abstract

The paper is concerned with the search for inexpensive alternative components of substrates of culture media for lactic acid bacteria. To be used in the food industry more extensively, lactobacilli should be produced in larger volumes. Bacteria-growing enterprises and those manufacturing probiotic preparations are interested in non-traditional components of growth media. However, it is quite a problem to create a cheap growth medium, because lactobacilli are very demanding of the content of certain components. Traditional culture media can include up to 40 components (peptones, yeast and vegetable extracts, vitamins, etc.). The research has proved that waste and by-products of potato starch production (potato juice and juice-containing water) can be used as components of a substrate to culture lactobacilli on. The strain used in the research was Lactobacillus plantarum 8R-A3. The growth kinetics of lactic acid bacteria has been analysed on different vegetable extracts. Tomato and cabbage extracts were used as traditional components of synthetic media to compare with. The findings have shown that on a substrate from by-products of potato starch production, after 96 hours of culturing at 37°C, the accumulation of Lactobacillus plantarum biomass is 20 g/l (on juice-containing water) and 25 g/l (on potato juice). Accumulation of bacteria wet weight has also been confirmed by determining the kinematic viscosity of the culture fluid. This parameter for potato juice after thermostatting was 6.77 mm2/s, which was somewhat higher than the viscosity of the tomato and cabbage extracts. It has been proved that by-products of potato processing ensure sufficient growth of lactic acid bacteria biomass. On the fourth day, the number of bacteria was 3·108 CFU/cm3. It has been shown how practical it is to use potato processing by-products as growth media substrates in culturing lactic acid bacteria Lactobacillus plantarum.