Interfacial Catalysis during Amylolytic Degradation of Starch Granules: Current Understanding and Kinetic Approaches

Abstract

Enzymatic hydrolysis of starch granules forms the fundamental basis of how nature degrades starch in plant cells, how starch is utilized as an energy resource in foods, and develops efficient, low-cost saccharification of starch, such as bioethanol and sweeteners. However, most investigations on starch hydrolysis have focused on its rates of degradation, either in its gelatinized or soluble state. These systems are inherently more well-defined, and kinetic parameters can be readily derived for different hydrolytic enzymes and starch molecular structures. Conversely, hydrolysis is notably slower for solid substrates, such as starch granules, and the kinetics are more complex. The main problems include that the surface of the substrate is multifaceted, its chemical and physical properties are ill-defined, and it also continuously changes as the hydrolysis proceeds. Hence, methods need to be developed for analyzing such heterogeneous catalytic systems. Most data on starch granule degradation are obtained on a long-term enzyme-action basis from which initial rates cannot be derived. In this review, we discuss these various aspects and future possibilities for developing experimental procedures to describe and understand interfacial enzyme hydrolysis of native starch granules more accurately.

Encapsulation of Amyloglucosidase in Chitosan-SDS Coacervates as a Means to Control Starch Hydrolysis in Plant-Based Beverages

“…Interestingly, corn starch still exhibits superior kinetic parameters compared to maltose (higher V max and lower K M values for corn starch than maltose for both free and encapsulated enzymes). This difference can be ascribed to amyloglucosidase preference for corn starch, as its structural composition provides multiple binding sites [50] specifically adapted for efficient enzyme activity. Additionally, the lower reaction velocity observed with maltose can be attributed to its simpler structure than starch.…”

Functional Roles of N-Terminal Domains in Pullulanase from Human Gut Lactobacillus acidophilus

“…Starch digestion in the human gastrointestinal tract (GIT) involves oral, duodenal, and small intestinal phases and a series of enzymes, including salivary and pancreatic amylases, maltase-glucoamylase, and sucrase-isomaltase . The digestibility of starch varies considerably based on botanical origin, granular crystal packing, and processing . Human digestive enzymes efficiently degrade α-1,4-linkages in starch but act less readily on α-1,6-linkages.…”

“…4 The digestibility of starch varies considerably based on botanical origin, granular crystal packing, and processing. 5 Human digestive enzymes efficiently degrade α-1,4-linkages in starch but act less readily on α-1,6-linkages. In contrast, pullulanases from the gut microbiota can efficiently degrade α-1,6-linkages in starch.…”

Advances in Amylases—What’s Going on?

“…With regard to the CAZy database ( [1]; http://www.cazy.org/ accessed on 14 October 2023) classifying carbohydrate-active enzymes into their sequence-based families, and based on the obtained knowledge, it is reasonable to consider that α-amylase enzyme specificity is present in four CAZy glycoside hydrolase (GH) families: GH13, GH57, GH119, and GH126 [2]. In other words, currently, of the 186 GH families in total [1], 4 may be considered α-amylase families [2]: (i) GH13-the main and the largest α-amylase family; (ii) GH57-the second and smaller α-amylase family; (iii) GH119-a very small family related to GH57; and (iv) GH126, in which the presence of pure α-amylase specificity has still not been proven definitively.…”

“…With regard to the CAZy database ( [1]; http://www.cazy.org/ accessed on 14 October 2023) classifying carbohydrate-active enzymes into their sequence-based families, and based on the obtained knowledge, it is reasonable to consider that α-amylase enzyme specificity is present in four CAZy glycoside hydrolase (GH) families: GH13, GH57, GH119, and GH126 [2]. In other words, currently, of the 186 GH families in total [1], 4 may be considered α-amylase families [2]: (i) GH13-the main and the largest α-amylase family; (ii) GH57-the second and smaller α-amylase family; (iii) GH119-a very small family related to GH57; and (iv) GH126, in which the presence of pure α-amylase specificity has still not been proven definitively. Particularly, the two former α-amylase families, GH13 and GH57, cover, in addition to α-amylase, most of the numerous amylolytic enzymes, such as α-glucosidase, pullulanase, amylopullulanase, isoamylase, cyclodextrin glucanotransferase, 4-α-glucanotransferase, α-glucan branching enzyme, α-glucan debranching enzyme, trehalose synthase, sucrose isomerase, etc.…”