Toxicity of some solvents and extractants towards Lactobacillus casei cells

Various organic compounds used as diluents, modifiers and extractants in lactic acid extraction have been tested to determine their toxicity towards Lactobacillus casei cells. The toxicity on molecular and phase level has been investigated. In general, the tested hydrocarbons were non-toxic on molecular level and showed variable toxicity on phase level. Among the tested alcohols octanol and oleyl alcohol were non-toxic, whereas decanol and dodecanol were toxic on the molecular level. All the alcohols showed high phase toxicity. The tested extractants were very toxic both on molecular (except for tridodecylamine) and on phase level. Two extraction systems composed of trioctylamine/oleyl alcohol and tridodecylamine/oleyl alcohol have also been studied. Both systems were non-toxic on molecular level and showed medium toxicity on phase level. They can be used successfully for in situ extractive fermentation of lactic acid.