Bacillus macerans

FIGURE 3.12 Biodegradation of 3,4-dihydroxybenzoate mediated by (a) 4,5-dioxygenase in Pseudomonas acidovorans and (b) 2,3-dioxygenase in Bacillus macerans. 

The third alternative for ring fission of 3,4-dihydroxybenzoate is exemplified by Bacillus macerans and B. circulans that use a 2,3-dioxygenase to accomplish this (Figure 8.30b)... 

Wolgel SA, JE Dege, PE Perkins-Olson, CH Juarez-Garcia, RL Crawford, E Mtinck, JD Lipscomb (1993) Purification and characterization of protocatechuate 2,3-dioxygenase from Bacillus macerans a new extradiol catecholic dioxygenase. J Bacterial 175 4414-4426. 

The reason that the cyclodextrin transglycosylase occurs only in Bacillus macerans and a few other thermophilic bacteria has not, as yet, been determined. Nevertheless, it is interesting to speculate about the possible evolutionary advantage that a bacterium might have by possessing the cyclodextrin transglycosylase. Because the cyclodextrins have no end... 

Prior to 1939, however, it was not known whether the cyclodextrins were products of the synthetic metabolism of Bacillus macerans, and therefore, perhaps, quite different from the components of starch, or whether they were formed by a single enzyme and therefore closely related to the starch structure. Then, Tilden and Hudson announced the discovery of a cell-free enzyme preparation from cultures of Bacillus macerans which had the ability to convert starch into the Schardinger dextrins without the production of maltose, glucose, or any other reducing sugars. They thus concluded that the Schardinger dextrins were either the true components of starch or closely related to such true components. 

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. ... 

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). 

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. 

Cyclodextrins are doughnut-shaped, macrocyclic oligosaccharides constructed of glucose units linked by a a(l - 4) bond. Hexamer, heptamer, and octamer are the most common, often called the a-, / -, and y-cyclodextrins, respectively (Fig. 1). Although cyclodextrin has been known as one of the oligoglucoses produced by Bacillus macerans since 1891 (2), its spectacular behavior as the possible enzyme model was first observed by Cramer and his co-worker (J). 

After the acid w are evaporated, the dried product is powdered and sieved. It can also be prepd by careful heating of dry starch. (Refs 6, 7, 8 10). If starch is hydrolyzed with Bacillus macerans, some crystalline products, such as a-dextrin, (CgHjQOj) are obtd (Ref 7). Crystallized products may also be prepd by decolorizing dextrin soln with animal charcoal and evaporating the product (Ref 10, p 346)... 

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