Immobilization of thermostable beta-glucosidase variants on acrylic supports for biocatalytic processes in hot water

• Two variants of the thermostable beta-glucosidase TnBgl1A (wt and N221S/P342L) from Thermotoga neapolitana were immobilized on acrylic supports (Eupergit (R) C, Eupergit (R) C250L, and cryogel) and evaluated at conditions close to the boiling point of water. Thermo-gravimetric analysis showed the supports to be stable <250 degrees C. Both wt and N221S/P342L were covalently bound to oxirane-groups respectively via glutaraldehyde spacers, and for coupling reactions 26 Lys and 20 Ser/Thr were surface-located. Immobilized enzymes were active on all supports in the temperature range 80-95 degrees C, but the observed specific activity was low (<= 19 U mg(-1)) using the cryogel. More than 91% of the initial activity was maintained after ten times recycling, and the same was recovered after 3 months storage at 4 degrees C for Eupergit (R) supports by simply incubating the preparation with bovine serum albumin. No storage loss was detectable on cryogels. The glutaraldehyde spacer improved activity on cryogels, but not on Eupergie supports. Immobilization on Eupergit (R) C250L yielded the highest observed specific activity (254 U mg(-1) for N221S/P342L) in a procedure including blocking of free oxirane-groups by BSA. This biocatalyst was used for on-line hydrolysis of quercetin-glucosides in a yellow onion extract at 80 degrees C, proving the immobilized biocatalyst to be promising in on-line systems for extraction and hydrolysis using hot pressurized water. (C) 2012 Elsevier B.V. All rights reserved.

Subject headings

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology (hsv//eng)

Keyword

Immobilization

Glycoside hydrolase family 1

Eupergit (R) C

Eupergit

(R) C250L

Cryogel

Publication and Content Type

art (subject category)

ref (subject category)