Kinetic characteristics of β-cyclodextrin production by cyclodextrin glycosyltransferase from newly isolated Bacillus sp. C26

Abstract

The kinetic characteristics of β-cyclodextrin production by a cyclodextrin glycosyltransferase (CGTase) produced by Bacillus sp. C26, a new isolate from a soil sample was investigated. Considering highest yield and initial production rate of β-cyclodextrin, among the starches examined, soluble starch, tapioca starch, sago starch, corn starch and rice starch, tapioca starch was the best substrate for this CGTase. The optimum temperature for tapioca starch gelatinization prior to its use as a substrate for β-cyclodextrin production was 65ºC. The yield and initial production rate of β-cyclodextrin increased with increasing starch concentration up to 6% and an enzyme concentration up to 48 U/g-starch. The kinetic parameters of V max and K m of β-cyclodextrin production from tapioca starch by CGTase were 1.59 mg/mL/h and 22.3 mg/mL, respectively. Considering high initial production rate and high yield of β-cyclodextrin, the optimum reaction temperature was at 50ºC. This study provided the necessary kinetic information that may be useful to define the most suitable condition for industrialized production of β-cyclodextrin with the high yield and productivity.

Effects of substrates and reaction conditions on production of cyclodextrins using cyclodextrin glucanotransferase from newly isolated Bacillus agaradhaerens KSU-A11

“…There are different approaches to enrich the yield of the target type of CD, including search for novel CGTase for this purpose, enzyme engineering of CGTase at central active site cleft (Takada et al 2003;Goh et al 2007) and, alternatively, modifying the substrates and enzymatic reaction conditions. Such parameters include starch source and concentration (Cheirsilp et al 2010), reaction pH (Hirano et al 2005), presence of certain additives and precipitants (Martins and Hatti-Kaul, 2003). In this study, we report the influences of different reaction parameters on the ratio and total yield of CDs produced by the action of CGTase from a newly isolated alkaliphilic Bacillus agaradhaerens KSU-A11 (Ibrahim et al 2010).…”

“…G1 (Sian et al 2005) and from Bacillus sp. C26 (Cheirsilp et al 2010), while soluble starch was the best substrate for CGTase from Klebsiella pneumoniae AS-22 (Gawande and Patkar, 2001). This suggested that the various sources of starch could affect the CDs production, which is probably caused by the differences in the starch granules structure and properties (Sian et al 2005; Goh et al 2007).…”

“…Interesting, percentage of γ-CD was higher at lower temperature than increased temperature with maximum percentage (15.2%) at 35ºC, although the total CDs yield (3.2 mg) was much less in comparison to the maximum yield obtained at 55ºC (6.9 mg). The enzymatic reaction is enhanced by temperature due to the higher kinetic energy, however, according to the thermostability of the enzyme, higher temperature leads to enzyme denaturation and loose of function in a short period of time resulting in lower yield of the product (Kitcha et al 2008;Cheirsilp et al 2010). …”

“…In addition, this ratio (80 U/g starch) is higher than the optimum ratio reported for β-CD production by CGTase from Bacillus sp. C26, where the optimum value was 48/g tapioca starch, (Cheirsilp et al 2010), and 50 U/g-starch for β-CD production by a CGTase from Bacillus circulans TISTR 907 (Charoenlap et al 2004)…”

Cyclodextrins

“…1) to provide cyclic a-(1!4)-linked glucooligosaccharides with six (a-CD), seven (b-CD), and eight glucose units (g-CD) (Rendleman 1999;Lichtenthaler 2010). This intramolecular transglycosylation is called cyclization reaction (Szejtli 1998;Cheirsilp et al 2010).…”