Sugar beet syrups in lactic acid fermentation – Part II Saving nutrients by lactic acid fermentation with sugar beet thick juice and raw juice

Renewable feedstock gain increasing attention in a time of rising oil prices and uncertainty about security of supply. Often those alternative resources do have high prices and processing costs. Fermentation processes are still of major significance in biotechnological processes. Sourcing cheap raw materials is a task of agricultural businesses. Apart from feedstock costs, energy and nutrients show a great impact on process economics. This actual study explores the potential of sugar beet thick juice and raw juice to act in a bifunctional manner, either as substrate or nutrient. Key finding of this studies are that even in absence of additional nutrients with raw juice lactic acid yields of up to 51,5% compared to 13,5% with thick juice and 2,4% with crystalline sugar were obtained. Even with raw juice an enentoermic purity of l(+)-lactic acid >98% could be achieved. The analytical comparison shows that raw juice can provide significant share of amino acids of a typical yeast extract addition while crystalline sucrose shows no contribution.