Potential new biocatalysts for biofuel production: The fungal lipases of Thermomyces lanuginosus and Rhizomucor miehei immobilized on zeolitic supports ion exchanged with transition metals

Abstract

Nanozeolite NaX ion exchanged with different transition metals (Mn 2+ ,Cu 2+ , Co 2+ , Zn 2+ , Ni 2+ ) was used as a solid support for the immobilization of the lipases of Thermomyces lanuginosus (TLL) and Rhizomucor miehei (RML). The nanozeolite-enzyme complexes were used as heterogeneous catalysts for the transesterification reaction of palm oil to fatty acid ethyl esters (FAEEs). The most relevant results were obtained with the Thermomyces lanuginosus enzyme immobilized on nanozeolitic supports ion exchanged with Ni 2+ . Although these zeolitic supports were able to immobilize a relatively small amount of the enzyme (43.7%) in comparison with the other nanozeolitic supports, the FAEE yields obtained with Nano-X/Ni/0.5M-TLL complexes were above 94%. These results revealed an unusual synergistic effect between the Thermomyces lanuginosus enzyme and the nickel ion-exchanged nanozeolitic support; this effect was not observed for the complexes prepared with the Rhizomucor miehei enzyme. Bioinformatics calculations were performed for both enzymes by taking into consideration the crystallographic structures of the enzymes and the zeta potential of the surface of the nanozeolitic supports. By combining calculations of the protein electrostatic potential surface and normal mode analyses in a model, we were able to propose an explanation for the synergistic effect between the lipases and the nanozeolitic supports. The synergistic effect could be explained through an allosteric mechanism describing the interaction between aspartic acid residues 102 and 158 of the Thermomyces lanuginosus lipase and the positively charged zeolitic support surface. This interaction results in the stabilization of the opening of the enzyme lid and leaves its catalytic triad permanently exposed to the reaction medium.

Biocatalysts based on nanozeolite-enzyme complexes: Effects of alkoxysilane surface functionalization and biofuel production using microalgae lipids feedstock

“…5). The important role played by nickel in enzyme immobilization and enzymatic activity has been reported previously [44,71] and was also observed here for the nanozeolite supports ion-exchanged with nickel.…”

“…Transesterification of palm oil to FAEEs using lipases of Thermomyces lanuginosus (TLL) and Rhizomucor miehei (RML) immobilized on nanosized NaX zeolite (FAU) ionexchanged with different transition metals has shown positive results. This has encouraged further synthetic and catalytic studies of enzyme-nanozeolite complexes with supports derived from different zeolite structures, and their application in the catalytic conversion of different non-edible biomasses to biodiesel [44]. Nev-ertheless, careful analysis of the literature shows that there have been no systematic studies describing the chemical modulation of nanozeolite support surfaces using chemical modifiers such as the alkoxysilane molecule (3-aminopropyl)trimethoxysilane (APTMS), with crosslinking using glutaraldehyde (GA), and the effects on the nanozeolite-enzyme complexes.…”

1,3‐Dioleoyl‐2‐palmitoyl glycerol (OPO)—Enzymatic synthesis and use as an important supplement in infant formulas

“…For efficient catalysis and yield, the immobilization material must be selected carefully based on its robustness, biocompatibility and recoverability (Temocin et al., 2018). Over the years, lipase immobilization on various support materials such as silica gel particles (Lee et al., 2006; Yang et al., 2010), macroporous resin (Yang et al., 2006), silica nanoparticles (Babaki et al., 2016), nanozeolites (Vasconcellos et al., 2015), carbon nanotubes (Fan et al., 2016), hybrid nanospheres (Verri et al., 2016) and chitosan microspheres (Palla et al., 2011) have been investigated for various uses. It has been reported that lipases immobilized on hydrophobic support materials show better catalytic properties than hydrophilic supports (Petkar et al., 2006; Wang et al., 2006).…”

Recent advances on sources and industrial applications of lipases

“…Also, Khasanov et al, have reported a study on the catalytic activity of fungal lipases derived from Oospora lactis , Penicillium sp., and R. microsporus . Further, fungal lipases derived from R. miehei and T. lanuginosus were studied for their immobilization on nanozeolite supports …”

“…Further, fungal lipases derived from R. miehei and T. lanuginosus were studied for their immobilization on nanozeolite supports. 116 Yeast Lipases. Yeast lipases constitute a very important source of lipases given their unique attributes in addition to their ease of culture that make them sought-after by many industries such as pharmaceutical, chemical, biodiesel, etc.…”