Syngenta Seeds, 12 Chemin Hobit. B.P. 27 31790 Saint Sauveur, France.
Enzyme Microb Technol. 2011 Jan 5;48(1):61-70. doi: 10.1016/j.enzmictec.2010.09.008. Epub 2010 Sep 17.
Enzymatic transesterification of triglycerides in a continuous way is always a great challenge with a large field of applications for biodiesel, bio-lubricant, bio-surfactant, etc. productions. The lipase B from Candida antarctica (CalB) is the most appreciated enzyme because of its high activity and its non-regio-selectivity toward positions of fatty acid residues on glycerol backbone of triglycerides. Nevertheless, in the field of heterogeneous catalysis, we demonstrated that the medium hydrophilic nature of the support used for its commercial form (Lewatit VPOC1600) is a limitation. Glycerol is adsorbed onto support inducing drastic decrease in enzyme activity. Glycerol would form a hydrophilic layer around the enzyme resulting in diffusional limitations during triglyceride transfer to the enzyme. Accurel MP, a very hydrophobic macroporous polymer of propylene, was found not to adsorb glycerol. Immobilization conditions using this support were optimized. The best support was Accurel MP1001 (particle size<1000 μm) and a pre-treatment of the support with acetone instead of ethanol enables the adsorption rate and the immobilized enzyme quantity to be maximized. An economical approach (maximization of the process net present value) was expanded in order to explore the impact of immobilization on development of an industrial packed bed reactor. The crucial ratio between the quantity of lipase and the quantity of support, taking into account enzyme, support and equipped packed bed reactor costs was optimized in this sense. The biocatalyst cost was found as largely the main cost centre (2-10 times higher than the investments for the reactor vessel). In consequence, optimal conditions for immobilization were a compromise between this immobilization yield (90% of lipase immobilized), biocatalyst activity, reactor volume and total investments.
酶法连续酯交换反应在生物柴油、生物润滑剂、生物表面活性剂等生产领域具有广泛的应用，一直是一个巨大的挑战。南极假丝酵母脂肪酶 B（CalB）是最受赞赏的酶，因为它具有很高的活性和对甘油三酯甘油骨架上脂肪酸残基位置的非区域选择性。然而，在多相催化领域，我们证明了其商业形式（Lewatit VPOC1600）所使用的载体的中等亲水性是一个限制因素。甘油会被吸附到载体上，导致酶活性急剧下降。甘油会在酶周围形成一层亲水性层，导致甘油三酯向酶转移过程中的扩散受限。丙烯的非常疏水性大孔聚合物 Accurel MP 被发现不吸附甘油。优化了使用该载体的固定化条件。最佳载体是 Accurel MP1001（粒径<1000 μm），并且用丙酮代替乙醇对载体进行预处理可以使吸附率和固定化酶的量最大化。为了探索固定化对工业填充床反应器开发的影响，扩展了一种经济方法（使过程净现值最大化）。从这个意义上讲，优化了考虑到酶、载体和配备的填充床反应器成本的酶与载体之间的关键比例。生物催化剂成本被发现是主要成本中心（比反应器容器的投资高 2-10 倍）。因此，固定化的最佳条件是在固定化产率（90%的酶固定化）、生物催化剂活性、反应器体积和总投资之间的折衷。
