engleski

Intensification of endo-1,4-xylanase extraction by coupling microextractors and aqueous two-phase system

The extraction of xylanase was performed using an aqueous two-phase system (ATPS) based on polyethylene glycol (PEG1540) and various salts. Preliminary studies in a batch extractor showed that the highest extraction efficiency, E = 79.63±5.21% and purification factor, PF = 1.26±0.25 were obtained with sodium citrate dihydrate-H2O-PEG1540 based ATPS for the extraction time of 10 min. The process was optimized using the experimental Box-Behnken design at three levels with three factors: extraction time (t), xylanase concentration (γ), and mass fraction of PEG in the ATPS (wPEG). Under optimal process conditions (γ = 0.3 mg/mL, wPEG = 0.21 w/w, and t = 15 min), E = 99.13±1.20% and PF = 6.49 ± 0.05 were achieved. In order to intensify the process, the extraction was performed continuously in microextractors at optimal process conditions. The influence of resi-dence time, different feeding strategies, and channel diameter on extraction efficiency and purifi-cation factor was further examined. Similar results were obtained in the microextractor for a residence time of τ = 1.03 min (E = 99.59±1.22% and PF = 6.61±0.07) as in the experiment carried out under optimal conditions in the batch extractor. In addition, a batch extractor and a continuous microextractor were used for the extraction of raw xylanase produced by Thermomyces lanuginosus on solid supports.

xylanase; extraction; aqueous two-phase system; optimization; batch extraction; continuous microextractor

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