Abstract

KINETIC OF ALCOHOL DEHYDROGENASE FROM THERMOANAEROBIUM BROCKII USING ALCOHOLS AND CARBONYL COMPOUNDS AS SUBSTRATES

Claudia Mucciante, Ester Junko Yoriyaz, Maria Cantarella and *Michele Vitolo

ABSTRACT

Alcohol dehydrogenase (ADH) is a versatile enzyme because it is capable of catalyzing alcohols to carbonyl derivatives and vice-versa by changing the pH of the reaction medium. This work was focused on the evaluation of basic kinetic parameters (activation energy, Vmax, KM, etc.) regarding the action of ADH from Thermoanaerobium brockii (ADHtb) on alcohols (2-propanol, 2-hexanol and 1-phenylethanol) and carbonyl compounds (acetaldehyde, acetone, 2-hexanone and acetophenone). Moreover, the use of the membrane reactor (MB) for the continuous conversion of a pro-chiralic ketone (2-hexanone) to a chiral alcohol (2-hexanol) was evaluated. A conversion yield of about 42% was attained by feeding the MR alternately with 2-hexanone (10mM) and 2-propanol (10mM) under the conditions as follows: 30oC, feeding rate = 2mL/h, UF-membrane = 500Da, agitation = 100 rpm, pH 8.8 (2-propanol solution) and pH 4.0 (2-hexanone solution).

Keywords: Alcohol dehydrogenase, Thermoanaerobium brockii, alcohols, carbonyl compounds.