Transesterification of castor oil catalyzed by a fermented solid produced by Burkholderia contaminans using a bioreactor coupled with ultrasound irradiation.

In this work, ultrasound was used to assist the ethanolysis of castor oil in a solvent-free system, catalyzed by a dry fermented solid containing the lipase from Burkholderia contaminans (BCFS). Reactions were done at 45°C. The maximum conversion in Erlenmeyer flasks was 71% in 96 h, using a loading of 9% (mass of BCFS in relation to the mass of triacylglycerols in the castor oil) and a molar ratio of ethanol:oil of 6:1, with addition of ethanol in 12 steps. In a packed-bed reactor containing 12 g of BCFS, the conversions were 78% in 48 h, and 83% in 72 h with an ethanol to oil molar ratio of 3:1 and treatment with an ultrasound probe, with maximum power of 500 W, frequency of 20 kHz, and 75% of the maximum power. These results are promising given that, with an ultrasound assisted bioreactor, a higher conversion in a shorter time was achieved, with a lower ethanol to oil molar ratio than was the case in the Erlenmeyer flasks without ultrasound.

Lipase immobilization on biodegradable film with sericin.

An ecofriendly and low-cost film composed by cassava starch, polyvinyl alcohol, and sericin blend (CS-PVA-SS) was synthesized, characterized, and applied as a novel support for Botryosphaeria ribis EC-01 lipase immobilization by enzyme-film-enzyme adsorption. Film revealed thickness between 230 and 309 µm and higher flexibility and malleability in comparison with film without SS. Based on p-nitrophenyl palmitate hydrolysis reaction, the activity retention of immobilized lipase was 987%. For optimal conditions, the yield in ethyl oleate was 95% for immobilized enzyme. Maximum yield was obtained at 49°C, molar ratio oleic acid:ethanol of 1:3, 1.25 g lipase film or 50 U (1.03 ± 0.03 mg protein) and 30 h. Even after seven cycles of use, immobilized lipase showed 52% reduction in ester yield. Biodegradable and biorenewable film is a promising material as a support to immobilize lipases and application in biocatalysis.

Production of starch-polyester bio-support for lipases immobilization: synergistic action of itaconic acid and nanoclay.

The objective of the present work was to develop biodegradable polymeric films (starch-PBAT) as support for the immobilization of lipases using sodium montmorillonite (MMT) as a reinforcing agent (2% w/w) and itaconic acid (IA - 0.5-1.5% w/w) as a compatibilizing agent. The films were produced through a two steps blow-extrusion. The addition of MMT increased the tensile strength and Tg of the films, while the presence of IA made the films more flexible, reducing their Tg. Lipases from Burkholderia cepacia LTEB11 were immobilized in the films by the adsorption method. The ester yield (% of ethyl oleate synthesis) has shown best results (96%, 6 h) for immobilized enzyme in the MMT film and six cycles of reuse were carried out until a reduction of 50% in the catalytic activity of the enzyme.