Conversion of Liquified Starch into Glucose Using a Novel Glucoamylase System

Abstract

The production of sweeteners from starch by enzymes has been commercially successful for many years. However, the real need for improving the current industrial processes for bioconversion of starch, which is chiefly obtained from the wet milling of corn, into the monosaccharides glucose and fructose still exists. Currently, most starch processing in the corn wet milling industry is achieved by using the enzymes α‐amylase, amyloglucosidase and glucose isomerase. This lecture deals with the production of glucose from dextrins by means of amyloglucosidase systems. The amyloglucosidase preparations commonly applied in industry are mixtures containing various enzymes. The maximum obtainable conversion of dextrins into glucose is determined by the thermodynamic and kinetic behaviour of the enzymes present in the amyloglucosidase mixtures. Therefore, knowledge of the composition and properties of the enzymes may lead to the decision to alter the composition of the enzyme system as a possible means of improving the glucose production process. In the search for various amylolytic components advanced chromatography techniques were applied and the enzymes found were used in saccharification studies.

Comparison of two glucoamylases from Hormoconis resinae

“…The optimal ratio of 1,6-to 1,4-glucosidic activity (as well as other amylolytic activities) in starch degradation depends greatly on the process and substrate used (Labout, 1985;Kennedy et al, 1988). Hence, large-scale purification of glucoamylase P may be important, if the debranching activity is to be used efficiently in industrial processes.…”

Comparative production of glucose and high fructose syrup from cassava and sweet potato roots by direct conversion techniques

“…Since Stargen is a commercial preparation having both α-amylase and glucoamylase, simultaneous liquefaction and saccharification could occur at room temperature itself, leading to considerable saving of energy. Labout (1985) reported that many commercially available glucoamylases contain small amounts of α-amylase released by the specific microbes during growth. This has been reported to aid the saccharification process.…”

“…Glucose syrups have been successfully used in the food industry for several years (Labout, 1985). Starch degradation to glucose is performed by two groups of enzymes such as alpha-amylases, which liquefy the starch to dextrins by cleaving the α-1 → 4 linkages in an endo-manner and glucoamylases, which saccharify the dextrins to glucose by attacking both α-1 → 4 and α-1 → 6 linkages at the non-reducing end (Labout, 1985). The liquezyme-X used in our study was an endoamylase while Dextrozyme-GA was a glucoamylase (T1).…”

Improvement and estimation of enzymic starch saccharification process

“…More recently, the. advantage of an adequate a-amylase activity in the glucoarnylase system employed in saccharification has been recognized (Labout, 1985). An increased rate of saccharification has been demonstrated both by applying immobilized enzyme technology (Link0 et al, 1979), and by using continuous extrusion processing for the liquefaction (Link0 et al, 1983).…”