Biocatalytic upgrading of levulinic acid to methyl levulinate in green solvents. (June 2019)

• Record Type: Journal Article
• Authors: Di, Xiaohui; Zhang, Yu; Fu, Junying; Yu, Qiang; Wang, Zhongming; Yuan, Zhenhong
• Is Part Of: Process biochemistry. Volume 81(2019)
• Page Start: 33
• Page End: 38
• Publication Date: 2019-06
• Subjects: Enzyme-Catalyzed esterification -- Levulinic acid -- Immobilized lipases -- Double-Peak relationship -- Ionic liquid; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2019.03.024
• Languages: English
• ISSNs: 1359-5113

Abstract

Highlights: Enzymatic upgrading of levulinic acid (LA) to methyl levulinate (ML) for fuel additive. 93% yield of ML was realized by Novozym ® 435 with [bmim][PF6 ]. Temperature exerted an unusual double-peak relationship over LA conversion. Graphical abstract: Synopsis Enzymatic esterification of biobased levulinic acid to methyl levulinate which can be used for flavoring, fuel additive and painting. Abstract: High value-added utilization of biomass-based platform chemicals has attracted increasing attention in recent years. The present study addresses the upgrading of levulinic acid (LA), an important biomass-based platform chemical, to methyl levulinate via a green and efficient enzymatic approach. Various lipases were assessed, with Novozym ® 435 displaying the best results for the esterification of LA. Subsequently, the effect of reaction medium on Novozym ® 435 catalyzed esterification was also studied. Compared with other reaction media, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6 ]) showed the greatest enhancement in yield by suppressing hydrolysis activity. The catalysts reusability was also improved by protection from [bmim][PF6 ] with 43.2% activity remained after 5 cycles, compared to that of 19.1% in 2-Me THF. Reaction temperature exerted an unusual double-peak relationship over methyl levulinate yield because Novozym ® 435 can simultaneously catalyze the esterification of LA and hydrolysis of methyl levulinate, each of which has a different optimal reaction temperature: ca. 30 °C and ca. 40 °C, respectively. When the molar ratio of LA/methanol, and the volume ratio of methanol/[bmim][PF6 ] were 1:5 and 1:3, respectively, methyl levulinate was obtained in 93% yield at 30 °C after 24 h with 10 mg/mL catalytic loading.