Fabrication of amphiphilic copolymeric gels with enhanced activity of immobilized enzymes in organic media

Efficient resolution of 3-aryloxy-1,2-propanediols using CLEA-YCJ01 with high enantioselectivity

The lipase YCJ01 from Burkholderia ambifaria is an organic solvent-stable enzyme and its activity can be activated by a hydrophobic solvent due to the "interface activation" mechanism. The activity of lipase YCJ01 increased by 2.1-fold with t-butanol as the precipitant even after cross-linking. The cross-linked enzyme aggregates of lipase YCJ01 (CLEAs-YCJ01) were found to be efficient for resolving 3-(4-methylphenoxy)-1,2-propanediol (MPPD) through sequential esterification. Excellent enantioselectivity towards MPPD (E > 400), excellent enantiomeric excess (ee) values of 99.2% for S-diacetates and 99.1% for R-monoacetate, and high yield (49.9%) were achieved using a high substrate concentration (180 mmol L-1). Thus, R- and S-type compounds with excellent ee values were simultaneously obtained, and MPPD was resolved by CLEAs-YCJ01. CLEAs-YCJ01 also showed high operational stability and maintained 91.2% residual activity after ten batches. To further evaluate the substrate specificity of CLEAs-YCJ01, a series of 3-aryloxy-1,2-propanediols (six analogues of MPPD) was applied as substrates for resolution. Under the optimized reaction conditions of reaction temperature of 35 °C, MPPD concentration of 180 mmol L-1, molar ratio of vinyl acetate to MPPD of 3 : 1, and isopropyl ether as the solvent, CLEAs-YCJ01 exhibited relatively strict enantioselectivity towards all the analogues of MPPD with a high yield (≥49.3%), favourable ee values (94.8-99.4%) for S-diacetates, and high ee values (92.1-99.2%) for R-monoacetate, which shows potential prospects for industrial applications.

Stable Bioactive Enzyme-Containing Multilayer Films Based on Covalent Cross-Linking from Mussel-Inspired Adhesives

The use of immobilized enzymes is mandatory for the easy separation of the enzyme, the unreacted substrates, and the obtained products to allow repeated enzymatic assays without cumbersome purification steps. The immobilization procedure is however critical to obtain a high fraction of active enzyme. In this article, we present an enzyme immobilization strategy based on a catechol functionalized alginate. We demonstrate that alkaline phosphatase (ALP) remains active in multilayered films made with alginate modified with catechol moieties (AlgCat) for long duration, that is, up to 7 weeks, provided the multilayered architecture is cross-linked with sodium periodate. This cross-linking reaction allows to create covalent bonds between the amino groups of ALP and the quinone group carried by the modified alginate. In the absence of cross-linking, the enzymatic activity is rapidly lost and this reduction is mainly due to enzyme desorption. We also show that NaIO4 cross-linked (AlgCat-Alp)n films can be freeze-dried and reused at least 3 weeks later without lost in enzymatic activity.