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

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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.

No MeSH data available.


Contour and response surface plots showing interaction effects of variables on β-cyclodextrin production.
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fig1: Contour and response surface plots showing interaction effects of variables on β-cyclodextrin production.

Mentions: Response surface plots and 2D contour plots were generated showing the effect of two independent variables on β-cyclodextrin production keeping the other at its central level (Figure 1). Interaction effect of enzyme CGTase and starch concentration shown in Figures 1(a) and 1(b) indicates that increase in potato starch concentration has favorable impact on β-CD production but increase in CGTase concentration does not show any positive effect. Figures 1(c) and 1(d) show the CD production as an interaction of CGTase concentration and temperature keeping the starch at its central level. Here, central range of temperature is found optimum but CGTase concentration has no impact on β-CD production. As shown in Figures 1(e) and 1(f), potato starch concentration as substrate has profound effect on CD production and its higher concentration is favorable irrespective of temperature. At higher temperatures like 65°C, the CD production decreased, probably due to denaturation of enzyme. Consequently, lower range of temperatures and higher starch concentration have shown very good CD production and hence their interaction effect was found significant.


β -Cyclodextrin Production by Cyclodextrin Glucanotransferase from an Alkaliphile Microbacterium terrae KNR 9 Using Different Starch Substrates
Contour and response surface plots showing interaction effects of variables on β-cyclodextrin production.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015009&req=5

fig1: Contour and response surface plots showing interaction effects of variables on β-cyclodextrin production.
Mentions: Response surface plots and 2D contour plots were generated showing the effect of two independent variables on β-cyclodextrin production keeping the other at its central level (Figure 1). Interaction effect of enzyme CGTase and starch concentration shown in Figures 1(a) and 1(b) indicates that increase in potato starch concentration has favorable impact on β-CD production but increase in CGTase concentration does not show any positive effect. Figures 1(c) and 1(d) show the CD production as an interaction of CGTase concentration and temperature keeping the starch at its central level. Here, central range of temperature is found optimum but CGTase concentration has no impact on β-CD production. As shown in Figures 1(e) and 1(f), potato starch concentration as substrate has profound effect on CD production and its higher concentration is favorable irrespective of temperature. At higher temperatures like 65°C, the CD production decreased, probably due to denaturation of enzyme. Consequently, lower range of temperatures and higher starch concentration have shown very good CD production and hence their interaction effect was found significant.

View Article: PubMed Central - PubMed

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.

No MeSH data available.