Browsing by Author "Innanen, Laura"

The aim of the study was to optimize growth media and its composition for one Lactobacillus strain. The purposes of the optimized culture media for fermentation were to maximize cell count and amount of viable cells during processing. The raw materials for growth media had to be suitable for industrial use. The study was performed by Bioscreen and fermentation tests in different growth media. At first ability of the strain to grow was tested by Bioscreen C with different raw materials and their compositions. According to literature, six carbon, four nitrogen sources and three other raw material were chosen to Bioscreen tests. Bioscreen C measured turbidity (OD value) of cultivation. According to the results from Bioscreen tests, optimal raw materials were chosen to the fermentation tests. The optimal carbon sources were whey permeate powder and glucose, the optimal nitrogen sources casein peptone and yeast extract and other raw materials manganesulfate, magnesiumsulfate and yeast extract. The cultivations were made in a bioreactor (Biostat Q). The starter strains were concentrated and freeze-dried. Samples from cultivated, concentrated and freeze-dried starter strain were analyzed (cell counts, optical density, growth rate, base consumption and survival-%). Results were compared to those obtained using control medium that is known to support the growth of the Lactobacillus strain. Lactobacillus strain was able to grow in different growth media. In Bioscreen tests compositions of growth media have major effect on lactobacilli growth. Bioscreen experiments revealed that in most cases the Lactobacillus strain grew to higher OD values in the composed media compared to control medium. In Bioscreen tests the sugar based growth media required more added minerals and yeast extract than whey permeate based media. Yeast extract was found to promote Lactobacillus growth in Bioscreen tests. In fermentation tests cells grew on growth media equally as on control media. Suitable alternative options for growth media were found from tests for further studies. Further studies can research functionality of the raw materials in production scale and preservation of the cell concentration during storage.