β-Cyclodextrin Production by Cyclodextrin Glucanotransferase from an Alkaliphile Microbacterium terrae KNR 9 Using Different Starch Substrates.

Kiransinh N Rajput,Ujjval B Trivedi,Kamlesh C Patel

doi:10.1155/2016/2034359

Kiransinh N Rajput, Ujjval B Trivedi + Show 1 more

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https://doi.org/10.1155/2016/2034359

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Abstract

Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) is an important member of α-amylase family which can degrade the starch and produce cyclodextrins (CDs) as a result of intramolecular transglycosylation (cyclization). β-Cyclodextrin production was carried out using the purified CGTase enzyme from an alkaliphile Microbacterium terrae KNR 9 with different starches in raw as well as gelatinized form. Cyclodextrin production was confirmed using thin layer chromatography. Six different starch substrates, namely, soluble starch, potato starch, sago starch, corn starch, corn flour, and rice flour, were tested for CD production. Raw potato starch granules were found to be the best substrate giving 13.46 gm/L of cyclodextrins after 1 h of incubation at 60°C. Raw sago starch gave 12.96 gm/L of cyclodextrins as the second best substrate. To achieve the maximum cyclodextrin production, statistical optimization using Central Composite Design (CCD) was carried out with three parameters, namely, potato starch concentration, CGTase enzyme concentration, and incubation temperature. Cyclodextrin production of 28.22 (gm/L) was achieved with the optimized parameters suggested by the model which are CGTase 4.8 U/L, starch 150 gm/L, and temperature 55.6°C. The suggested optimized conditions showed about 15% increase in β-cyclodextrin production (28.22 gm/L) at 55.6°C as compared to 24.48 gm/L at 60°C. The degradation of raw potato starch granules by purified CGTase was also confirmed by microscopic observations.

Highlights

Cyclodextrins are cyclic oligosaccharides commonly composed of six, seven, or eight D-glucose units (α, β, and γ-cyclodextrins, resp.) joined by α-(1, 4) glycosidic bonds
Different starch substrates were tested for βcyclodextrin production using appropriately diluted purified enzyme
As purified CGTase is able to degrade raw potato starch and produce cyclodextrins, we examined the degradation of these

Summary

Introduction

Cyclodextrins are cyclic oligosaccharides commonly composed of six, seven, or eight D-glucose units (α-, β-, and γ-cyclodextrins, resp.) joined by α-(1, 4) glycosidic bonds. Cyclodextrin molecules have hydrophilic outside, which can dissolve in water, and hydrophobic nonpolar cavity, which is described as a “microheterogeneous environment” [1]. Because of this unique property, CDs can form molecular inclusion complexes (host-guest complexes) with a wide range of solid, liquid, and gaseous compounds and have found various applications in the field of medicine, food, pharmaceuticals, and cosmetics [2, 3]. Cyclodextrins (CDs) are produced as a result of intramolecular transglycosylation (cyclization) reaction during degradation of starch by CGTase enzyme. The CGTase is a multifunctional enzyme and catalyzes four different reactions: cyclization, disproportionation, coupling, and weak hydrolysis reaction [4]. Gelatinized starch swells irreversibly creating larger surface/volume ratio for enzymatic reaction [9,10,11]

Materials and Methods

Results and Discussion

Conclusion