To improve enzyme catalytic efficiency

the ionic liquid/buffer biphasic system was used as bio-catalytic medium in catalytic hydrolysis of alliin to the sulfur-containing compounds by alliinase. The results showed that the enzyme activity was higher for 25% ［BMIM］PF6/ buffer biphasic system than for pure buffer system but inhibited markedly by excess amount of ［BMIM］PF6

and the thermal stability of the enzyme was enhanced. Using natural alliin as substrate

the Km of 0.591 mmol·L-1 and the Vmax of 0.316 mmol·L-1·min-1 were obtained for the enzyme catalytic reaction in ［BMIM］PF6/buffer biphasic system

and the Vmax/Km ratio was about 2 fold of buffer monophasic system. In addition

in order to rising yield of essential oil

a combination technique of ionic liquid ［BMIM］PF6

as bio-catalytic medium and extraction agent

and ultrasound-microwave-assisted was used for preparation and extraction of onion essential oil. The optimized conditions established were as follows:［BMIM］PF6 concentration 20%(vol)

enzymatic time 2 h

ratio of raw material to liquid 1∶1.5

extraction temperature and time 25℃ and 50 s

and ultrasound-microwave power 150 W.Total 22 substances were identified in the onion essential oil prepared from fresh onion and 19 kinds of them sulfur-containing compounds by GC-MS analysis.To improve enzyme catalytic efficiency

the ionic liquid/buffer biphasic system was used as bio-catalytic medium in catalytic hydrolysis of alliin to the sulfur-containing compounds by alliinase. The results showed that the enzyme activity was higher for 25% ［BMIM］PF6/ buffer biphasic system than for pure buffer system but inhibited markedly by excess amount of ［BMIM］PF6

and the thermal stability of the enzyme was enhanced. Using natural alliin as substrate

the Km of 0.591 mmol·L-1 and the Vmax of 0.316 mmol·L-1·min-1 were obtained for the enzyme catalytic reaction in ［BMIM］PF6/buffer biphasic system

and the Vmax/Km ratio was about 2 fold of buffer monophasic system. In addition

in order to rising yield of essential oil

a combination technique of ionic liquid ［BMIM］PF6

as bio-catalytic medium and extraction agent

and ultrasound-microwave-assisted was used for preparation and extraction of onion essential oil. The optimized conditions established were as follows:［BMIM］PF6 concentration 20%(vol)

enzymatic time 2 h

ratio of raw material to liquid 1∶1.5

extraction temperature and time 25℃ and 50 s

and ultrasound-microwave power 150 W.Total 22 substances were identified in the onion essential oil prepared from fresh onion and 19 kinds of them sulfur-containing compounds by GC-MS analysis.