title: Enhanced production of γ-cyclodextrin by optimization of reaction of γ-cyclodextrin glycosyltransferase as well as synchronous use of isoamylase.
abstract: In this study, we examined the production of γ-cyclodextrin (γ-CD) using γ-cyclodextrin glycosyltransferase (γ-CGTase) from Bacillus clarkii 7364. We investigated a variety of factors that affect the yield of γ-CD, including key factors such as solvent, substrate, temperature, pH, enzyme dosage. After optimising the reaction parameters, a 50.4% (w/w) yield of γ-CD was obtained with 15% (w/v) potato starch and cyclododecanone (which could be easily removed). In order to further enhance the production of γ-CD, we constructed the γ-CGTase mutant A223K by site-directed mutagenesis, and used it synchronously with the isoamylase obtained from Thermobifida fusca. At pH 7.0 and 50 °C, 72.5% (w/w) γ-CD yield was achieved after 10h, which was 22.1% higher than that obtained using γ-CGTase alone, and represents the highest yield reported to date. The substantially higher yield and selectivity of γ-CD obtained in the present study provides the basis for the industrial-scale production of γ-CD.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Ave., Wuxi, Jiangsu 214122, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
mesh_terms: D000192:Actinomycetales / Q000201:enzymology*; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods*; D007517:Isoamylase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000737:chemistry; D013696:Temperature; D047408:gamma-Cyclodextrins / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D047408:gamma-Cyclodextrins; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D007517:Isoamylase; C023792:gamma-cyclodextrin
keywords: Bacillus clarkii 7364; Cyclodextrin glycosyltransferase; Cyclododecanone; Isoamylase; Synchronous production; γ-Cyclodextrin