Exploring the fermentation characteristics of acetic and lactic acid bacteria for the development of novel sugar-based beveragesRaner, Blaž (Avtor) Čadež, Neža (Mentor) O Sullivan, Tadhg (Komentor) fermented beveragesnovel product developmentfermentationbioreactorsacetic acid bacterialactic acid bacteriasugar-based mediummedium optimizationgluconic acidlactic acid2-ketogluconateFermented products are well known for their nutritional and health benefits. Recently, there has been an increasing interest for novel fermented beverages by the consumers. This presents an opportunity for the food industry to explore alternative substrates and microorganisms for the production of novel fermented drinks. In our research we focused on gaining a deeper understanding of the fermentation characteristics of two selected strains of Lactobacillus plantarum and Acetobacter orientalis bacteria, and on creating an optimized sugar based medium that could serve as a basis for the development of novel fermented beverages. Previously, in company Heineken they tested both strains for the production of fermented beverages using natural substrates such as barley wort and apple juice. However, natural substrates are quite complex and can vary in composition between different batches, potentially affecting the fermentation process and causing variations in the final products. Therefore, we developed and optimized a novel sugar-based medium that is more defined than natural substrates. The goal of the optimization was to reduce the cost of the sugar medium, produce a higher concentration of the target organic acid in the product (lactic acid with L. plantarum and gluconic acid with A. orientalis), and improve the sensory properties of the fermented sugar medium. We approached the optimization of the medium by testing different concentrations of components in the medium- Na3-citrate, KH2PO4, yeast nutrient type and concentrations, MgSO4, MnSO4 and sugar. We studied the fermentation dynamics of the strains in sugar media with varying compositions to gain deeper insights into their fermentation properties. The parameters analyzed included medium acidification, production of target organic acids, sugar consumption, biomass production and the sensory properties of the final product. Additionally, we examined the production of 2-ketogluconate in A. orientalis. We successfully developed optimized sugar media specifically tailored for the fermentation of L. plantarum and A. orientalis, which are cheaper than the initial formulations and exhibit improved sensory properties after fermentation. Selected sugar media formulations were also scaled up for fermentation, with pilot-scale trials conducted at 1400 L for L. plantarum and at both 0.75 L and 7 L for A. orientalis.[B. Raner]20252025-05-22 07:15:08Magistrsko delo/naloga169280sl