BIOCONVERSION OF CITRUS AROMA COMPOUNDS BY PICHIA-PASTORIS

After induction of alcohol oxidase, active Pichia pastoris cells were grown in model alcohol solutions and orange aroma, a by-product rich i n potential alcohol substrates for bio-oxidation to aldehydes. Acetald ehyde production efficiency was 60% at 0.1% ethanol, decreasing with i ncreasing ethanol, Acetaldehyde, propanal, and octanal were generated using the Pichia system with orange aroma as substrate. Acetaldehyde c oncentration doubled during a 24h reaction time at 30 degrees C, In co ntrast to use of isolated alcohol oxidase, the whole cell system had t he advantage of cofactor regeneration and associated enzyme systems, i ncluding formaldehyde dehydrogenase, Sensory differences were found in the full strength biomodified aroma, Presented in a paired comparison aroma test, to a trained panel it rated higher for the attributes ora nge character, freshness, and fruitiness than the unmodified control.