Alpha chymotrypsin coated clusters of Fe3O4 nanoparticles for biocatalysis in low water media

Magnetically recyclable catalytic nanoparticles grafted with Bacillus subtilis β-glucosidase for efficient cellobiose hydrolysis

This study reports covalent immobilization of β-glucosidase (BGL) from Bacillus subtilis PS on magnetically recyclable iron nanoparticles for enhancing robustness, facile recovery and reuse of enzyme. Immobilized BGL iron nanoparticles (BGL-INPs) were characterized by various biophysical techniques viz. TEM, DLS, FTIR and CD spectroscopy. The efficiency and yield of immobilization were 89.78 and 84.80%, respectively. After immobilization, optimum pH remained 6.0 whereas optimum temperature upraised to 70 °C whereas apparent Km and Vmax shifted from 0.819 mM to 0.941 mM and 54.46 to 57.67 μmole/min/mg, respectively. Immobilization conferred lower activation energy and improved pH and thermal stabilities. The BGL-INPs retained 85% activity up to 10th cycle of reuse and hydrolyzed more than 90% of cellobiose to glucose within 30 min. Conclusively, improved pH, thermal stability and excellent reusability over free enzyme make BGL-INPs a promising candidate for sustainable bioethanol production and other industrial applications.

Bio-affinity mediated immobilization of lipase onto magnetic cellulose nanospheres for high yield biodiesel in one time addition of methanol

To synthesis biodiesel from palm oil in one-time addition of methanol and solvent-free medium using CBD fused with C-terminal of lipase from G. stearothermophilus (GSlip-CBD) was immobilized onto magnetic cellulose nanosphere (MCNS). The immobilized matrix traits were preconceived by FT-IR, TEM and XRD. Perceptible biodiesel yield 98 and 73% was synthesized by GSlip-CBD-MCNS in 4 h and GSlip-MCNS in 6 h under the optimized conditions of oil:methanol ratio (1:3.5), temperature (55 and 50 °C) and enzyme loading (15 U). Intriguingly, the operational stability of GSlip-CBD-MCNS was an easily attainable owing to the magnetic properties and could be reused up to 8th and19th cycles with 94 and 45% of biodiesel yield respectively, compared to GSlip-MCNS. Thus GSlip-CBD-MCNS could be a potential biocatalyst for higher yield of biodiesel and reusability in one step addition of methanol.

Lipase coated clusters of iron oxide nanoparticles for biodiesel synthesis in a solvent free medium

Methyl or ethyl esters of long chain fatty acids are called biodiesel. Biodiesel is synthesized by the alcoholysis of oils/fats. In this work, lipase from Thermomyces lanuginosus was precipitated over the clusters of Fe3O4 nanoparticles. This biocatalyst preparation was used for obtaining biodiesel from soybean oil. After optimization of both immobilization conditions and process parameters, complete conversion to biodiesel was obtained in 3h and on lowering the enzyme amount, as little as 1.7U of lipase gave 96% conversion in 7h. The solvent free media with oil:ethanol (w/w) of 1:4 and 40°C with 2% (w/w) water along with 20% (w/w) silica (for facilitating acyl migration) were employed for reaching this high % of conversion. The biocatalyst design enables one to use a rather small amount of lipase. This should help in switching over to a biobased production of biodiesel.