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in Wiley Online Library (wileyonlinelibrary.com).Lipase was covalently attached to multiwalled carbon nanotubes (MWNTs). Structural changes of the lipase upon attachment onto MWNTs were analyzed through circular dichroism and FTIR spectroscopy. The conjugate was utilized for the resolution of a model compound (R,S)-1-phenyl ethanol, and the reaction medium was n-heptane. The enzymatic resolutions were carried out at temperatures from 35 to 60 C. The results show that the lipase attached onto MWNTs has significantly affected the performance of the enzyme in terms of temperature dependence and resolution efficiency. The activity of MWNT-lipase was less temperature-dependent compared with that of the native lipase. The resolution efficiency was much improved with MWNT-lipase. MWNT-lipase retained the selectivity of the native lipase for (R)-1-phenyl ethanol. The consecutive use of MWNT-lipase showed that MWNT-lipase had a good stability in the resolution of (R,S)-1-phenyl ethanol. V V C 2010 American Institute of Chemical Engineers AIChE J, 56: 3005-3011, 2010

Using 5-sulfoisophthalic acid as the ligand, tin porous coordination polymer (SnPCP) was synthesized on polydopamine-coated MnO 2 (MnO 2 −PDA). The novel composite SnPCP@MnO 2 −PDA was used for conversion of glucose into 5-hydroxymethylfurfural (HMF). The tetrahedral-coordinated tin and the sulfonic groups of the ligand catalyze glucose isomerization to fructose and fructose dehydration to HMF, respectively. Thus, the composite is a bifunctional catalyst. The porous structure of SnPCP of the composite facilitates the transport of glucose, intermediate, and HMF within the catalyst. In addition, MnO 2 −PDA was found to be able to catalyze the conversion of glucose to HMF. The synergistic effect of SnPCP and MnO 2 − PDA achieved HMF yields of 55.8% in DMSO and 41.2% in water/THF. Consecutive use of SnPCP@MnO 2 −PDA demonstrated that, after 5 cycles, the activity loss is not significant in terms of the HMF yield and glucose conversion.

Carboxyl-functionalized graphene oxide (GO−COOH) was utilized to immobilize lipase. Fourier transform infrared (FTIR), UV−visible, and X-ray photoelectron (XPS) spectra were measured to characterize lipase immobilization. At the optimal temperature of 40 °C, the immobilized lipase retains 80% of the hydrolytic activity of the native lipase. For catalyzing the enantioselective reaction in the organic solvent heptane, at 50 °C (optimal), the catalysis efficiency of the immobilized lipase is 1.6 times that of native lipase, and the immobilized lipase retains the selectivity of the native lipase. This work demonstrates that graphene oxide is a suitable support for immobilization of lipase for catalysis in organic solvent.

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