Cross-linked enzyme aggregates of recombinant cyclodextrin glycosyltransferase for high-purity β-cyclodextrin production: High-purity cyclodextrin production using CGTase as biocatalyst

BACKGROUNDHigh-purity -, -, or -cyclodextrin (CD) production using cyclodextrin glycosyltransferase (CGTase) as biocatalyst to cyclize starch is advantageous owing to its low cost of purification and product specificity. Several approaches have been investigated to enhance product specificity of CGTase, such as new CGTase isolation, CGTase gene (cgt) mutation, and chemical addition. RESULTSRecombinant CGTase was cross-linked by glutaraldehyde to obtain cross-linked enzyme aggregates of recombinant CGTase (CLEA-CGTase) at 85 degrees C because free CGTase showed high product specificity at 85 degrees C. The CLEA-CGTase was prepared under the conditions 75 U mL(-1) CGTase with 0.1% (v/v) glutaraldehyde for 10 min at 85 degrees C after optimization first, and produced a high proportion of -CD from soluble starch at 50 degrees C in the conversion system. The conversion process was carried out with 10 to 200 U mL(-1) CLEA-CGTase, resulting in 100% -CD from soluble starch after 420 min conversion of the potato starch solution at 50 degrees C. And the proportion of -CD was still higher than 90% when 8000 U mL(-1) CLEA-CGTase was added. CONCLUSIONSCLEA technology maintained CGTase conformation of 85 degrees C, and produced a high proportion of -CD at 50 degrees C. This research showed the CLEA technology kept the conformation of enzyme for specific product production. (c) 2018 Society of Chemical Industry