BACTERIAL BIOCONVERSION OF PRIMARY ALIPHATIC AND AROMATIC ALCOHOLS INTO ACIDS - EFFECTS OF MOLECULAR-STRUCTURE AND PHYSICOCHEMICAL CONDITIONS

The biotransformation of four alcohol substrates (butanol, 2-methylbut anol, 3-methylbutanol and 2-phenylethanol) into their acids was studie d using a strain of Acetobacter aceti. Bioconversion yields depended o n the molecular structure of the alcohol. Biotransformation of high co ncentrations of alcohols was possible until the precursor reached an i nhibiting concentration (3.8 g dm(-3) for butanol and 3-methylbutanol, 4.2 g dm(-3) for 2-methylbutanol). In contrast, biotransformation of 2-phenylethanol decreased when alcohol concentration was higher than 0 .3 g dm(-3). Dissolved oxygen concentrations and pH conditions of the medium were important factors in improving bioconversion. Transformati on of 2-methylbutanol into the corresponding acid was increased when d issolved oxygen partial pressure increased from 60 to 80% and regulati on at pH 6 allowed an increase in the production of butyric acid from butanol.