[Objective]The research aimed to study the feasibility of synthesis of conjugated linoleic acid (CLA) under supercritical CO2 with lionleic acid isomerase from Lactobacillus acidophilus.[Method]Taken lionleic acid isomerase from L. acidophilus for materials, the effects of temperature and pressure of supercritical CO2,memory pH, water activity on the systhesis of conjugated linoleic acid were studied on the basis of review of substrate solubility,activity changes of enzyme after treated with supercritical CO2.[Result]The results showed that, under the supercritical fluid CO2 ,the solubility of lionleic acid elevates with the increase of the supercritical fluid CO2 pressure, but reduces with the increase of the temperature.Lionleic acid has good solubility as the pressure exceeds 15 MPa. The supercritical fluid CO2 pressure and the treating time have more effects on the activity of the enzyme powder.The better condition of bioconversation in supercritical fluid CO2 is 15 MPa,37 ℃, with the enzyme's optimum pH value of 4.0 and a moisture activity of 0.4-0.5.[Conclusion]Preliminary research showed that the synthesis of CLA in supercritical CO2 with enzymic method was desirable,but the optimum condition of enzymic catalytic reaction in supercritical CO2 and selectivity of enzyme in reaction system needed to be explored for next step.%[目的]探讨在超临界CO2中利用嗜酸乳杆菌亚油酸异构酶转化亚油酸、合成共轭亚油酸(CLA)的可行性.[方法]以嗜酸乳杆菌亚油酸异构酶为研究对象,在考察底物溶解性、酶粉经超临界CO2处理后活性变化的基础上,研究超临界CO2温度、压力、酶粉的记忆pH和水分活度对共轭亚油酸合成的影响.[结果]结果表明,底物亚油酸在超临界CO2中的溶解度随压力和温度而改变,当压力超过15 MPa时,底物开始具有较好的溶解性;酶粉经超临界CO2处理后的活性随压力和时间产生较大变化;超临界CO2压力、温度、酶粉的记忆pH和水分活度均对CLA产率产生影响,单因素试验所得的较好条件是压力为15 MPa,温度为37 ℃,pH值为4.0,水分活度为0.4～0.5.[结论]初步研究表明,在超临界CO2中酶法合成CLA是可行的,但催化反应的条件优化、酶在体系中的选择性等都有待进一步探索.
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