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- Title
Biocatalytic Heterogeneous Processes of Low-Temperature Synthesis of Diol Monoesters.
- Authors
Kovalenko, G. A.; Perminova, L. V.; Shashkov, M. V.; Beklemishev, A. B.
- Abstract
A study was made of the low-temperature synthesis of esters of heptanoic (enanthic, C7:0) acid and various diols using heterogeneous biocatalysts prepared by the adsorptive immobilization of the recombinant lipase rPichia/lip on macroporous carbon aerogel. The substrates were diols differing in length of the carbon skeleton (2 to 6 C atoms), position of the OH group, and isomerism of the carbon skeleton, namely, 1,2-ethanediol (ethylene glycol) and its oligomers (dimers and trimers), 1,2-propanediol (propylene glycol), 1,3‑propanediol, 1,4-butanediol, 1,6-hexanediol, and 2-ethyl-1,3-hexanediol. The esterification and synthesis of monoesters of heptanoic acid were carried out in batch reactors under very mild conditions (20 ± 2°C, 1 bar). The properties of the prepared biocatalysts, such as enzymatic activity, substrate specificity, and operational stability, were investigated depending on the structure of the diol molecule and the nature of the organic solvent (chloroform, hexane, acetone). It was found that C2–C4 short-chain diols irreversibly inhibited the immobilized lipase, and the biocatalyst was completely inactivated within 1–3 reaction cycles. The maximum activity (83 U/g) and the conversion of acid (94% in 24 h) were observed in the esterification of heptanoic acid with 1,6-hexanediol; under the studied conditions, the fraction of monoester was more than 99%. A correlation was found between the biocatalytic activity and the molecular length of symmetric diols: the esterification reaction rate increased with increasing distance between the terminal OH groups. Because chloroform inactivated the adsorbed rPichia/lip, the conditions for the reactivation of the biocatalysts were selected by replacing the reaction medium: the solvent by hexane and the diol by butanol.
- Subjects
GLYCOLS; ORGANIC solvents; ETHYLENE glycol; BUTANEDIOL; LIPASES; PROPYLENE glycols; ENZYMES
- Publication
Kinetics & Catalysis, 2022, Vol 63, Issue 2, p188
- ISSN
0023-1584
- Publication type
Article
- DOI
10.1134/S0023158422020045