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Rhamnolipids as affinity foaming agent for selective collection of β-glucosidase from cellulase enzyme mixture

Paper ID Volume ID Publish Year Pages File Format Full-Text
17476 42671 2011 6 PDF Available
Title
Rhamnolipids as affinity foaming agent for selective collection of β-glucosidase from cellulase enzyme mixture
Abstract

Selective and effective separation can potentially be achieved with affinity foam fractionation using simple foaming setup and operation. In this study the use of affinity foam fractionation for selective collection and enrichment of β-glucosidase from a cellulase enzyme mixture was evaluated. Rhamnolipids, a group of glycolipids produced most commonly by Pseudomonas aeruginosa, were used as the affinity foaming agent, because of their foaming property and the presence of dirhamnose moiety (a potential substrate analog for β-glucosidase) in some rhamnolipids. The effects of aeration rate, medium pH, cellulase concentration and rhamnolipid concentration on the foam fractionation performance were examined. Among the pH studied (3.1, 5.0, 7.0 and 9.0), pH 5 was clearly the optimal for selective enrichment of β-glucosidase, presumably corresponding to the high binding affinity between the enzyme and the substrate analog (dirhamnose). With adequate rhamnolipid concentrations (≥0.1 g/L), the aeration rate of 0.1 L/min (i.e., 2 VVM) for 50 ml test samples was found to give the highest enrichment; higher aeration rates produced wetter foam and, thus, lower (diluted) enzyme activity in the foamate. The enrichment increased with the increasing rhamnolipids-to-cellulase ratio, in the range of 0–2 (w/w) investigated in this study. The finding indicated that rhamnolipids were the limiting compounds in these systems so that the amount of surfactant–enzyme complexes formed and removed into the foam phase would increase when more rhamnolipids were added. At the rhamnolipids-to-cellulase ratio of 2, the β-glucosidase activity in the foamate was about 9 times as high as the activity in the original sample of cellulase mixture and about 17 times the activity in the remaining solution (after foaming). The overall FPU (filter paper unit, a measurement of total cellulase activity) and the activities of endo- and exo-glucanases were only enriched 70–150%. The feasibility of affinity foam fractionation was demonstrated.

Keywords
Affinity separation; Foam fractionation; Cellulase; Rhamnolipids; β-Glucosidase; Trichoderma reesei
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Rhamnolipids as affinity foaming agent for selective collection of β-glucosidase from cellulase enzyme mixture
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 48, Issue 2, 8 February 2011, Pages 175–180
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us