Amylases of Bacillus macerans

Cyclodextrins, products of the degradation of starch by an amylase of Bacillus macerans(1), have been studied in terms of chemical modifications, mainly for the purpose of developing efficient enzyme mimics(2). Not only their unique cyclic structures, but also their ability to form Inclusion complexes with suitable organic molecules, led us to Investigate the total synthesis of this class of molecules(3) We describe here an approach to a total synthesis of alpha(l), gamma(2), and "iso-alpha" cyclodextrin (3). 

Cyclodextrins, also called Schardinger dextrins, cycloamyloses, or cyclo-glucans, are a family of cyclic oligosaccharides obtained from starch and related compounds by the action of the amylase of Bacillus macerans. They were discovered by Villiers in 1891 [10] and the first detailed description of their properties and isolation was made by Schardinger in 1903 [11-13]. 

It must be conceded that there is one case where the products of amylase action are probably not primary products formed in this way. This is the degradation of starch with the amylase from Bacillus macerans. The cycloamyloses formed by this enzyme are probably not preformed in the starch (see also Section II, 10). 

Several methods can be used for separation. A current favorite is to use a series of compounds called cyclodextrins, which have been found to associate preferentially with one form of optical isomer more than the other. Figure 31-9 shows a diagram of alpha cyclodextrin. They are obtained by the action of Bacillus macerans amylase on starch to form homogeneous cyclic alpha- 1,4-D-glucopyranose units. Alpha is the hexa ring, beta is the... 

CDs are produced from starch by the action of Bacillus macerans amylase or the eitzyme cyclodextrin transglycosylate (CTG) [16-19]. The latter enzyme can be used to produce CDs of specific sizes by controlling the reaction conditions. In the past few years, enantiomers have been resolved using peralkylated a-, and y-CDs dissolved in polysiloxanes and coated within glass or fused silica capillary tubing [20, 21]. Subsequently, the CDs were linked to the solid supports. In 1979, Harada etal. [22] polymerized and crosslinked a CD with a gel support, and the CSP developed was tested for the chiral resolution of mandelic acid and its derivatives. Various workers have subsequently bonded all three CDs with different solid supports [23-33]. Of course, these CDs bonded to gel support have been used for the chiral resolution of different racemates, but they suffer from certain drawbacks because of their poor mechanical strength and efficiency in both GC and HPLC. An improvement to these... 

Preparation of Macerans Amvlase. Macerans amylase was separated from cultures of Bacillus macerans in 1939 by Tilden and Hudson (35). The enzjnmatic hydrolysis of starch by this organism and the detection of the crystalline dextrins was first reported by Villiers... 

Thus, Freudenberg concluded that the cyclodextrins are not preformed in starch, but that their formation is made possible by the helicity of the starch chain. Freudenberg s hypotheses concerning the starch structure (that is, the amylose fraction) and the Bacillus macerans amylase mechanism have been confirmed by X-ray crystallography and chromatographic techniques. ... 

In 2002, Do et al. [85] proposed a pathway for the enzymatic synthesis of (-)-menthyl a-maltoside and a-maltooligosides from (-)-menthyl a-glucoside using cyclodextrin glucanotransferase obtained from Bacillus macerans. The reaction can be performed in a reactor containing (-)-menthyl a-glucoside, the enzyme and soluble starch the yield was about 80% 15% (-)-menthyl a-malto-side and 65% (-)-menthyl a-maltooligosides, respectively. Treatment of the starch with a-amylase can raise the proportion of (-)-menthyl a-maltoside. 

In the authors experiments, the cycloamyloses by very prolonged action of the enzyme did vanish with the production of maltose. It is not clear if this is an action of the Bacillus macerans amylase or of another enzyme present in the bacillus. After a very long time the yield of fermentable sugar was about 60% of the starch. 

The action of /8-amylase on starch partially degraded by the Bacillus macerans amylase was determined (Table XXVII). The amount of maltose decreases with decreasing degree of polymerization. When the... 

The concept biochemical processing of vegetable gums is exemplified by the use of alpha amylase to depolymerize starch and by the Bacillus macerans transglycosylase in the formation of cycloamylose. Most biochemical processes are presently not... 

Cyclodextrins are obtained when starch is digested with bacillus macerans amylase. They appear not to have any biological significance. They cannot be used as carriers as the complexes are too unstable - on the way from one side of the path to the other the complex would decompose. 

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