Kinetic of Sorghum starches bioconversion using various a-amylases

Industrial enzymology is an important branch of biotechnology. Enzymes offer alternative ways of making products previously made using conventional chemical. Originally, acid conversion was used to produce glucose syrups but today alpha-amylase are used to hydrolyze starches.
Corn starches are the most useful industrially despite that Sorghum (Sorghum bicolor (L.) Moench) starches exhibit interesting properties. These properties show variability according to genotype and influence the digestibly of starch in the presence of amylases. The aim of this research is to determine the susceptibility of isolated starches from different cultivars of sorghum cultivated in hyper arid ecosystems of the Sahara of Algeria to the bioconversion using pure α-amylases and so to study the influence of the genotype of sorghum on the liquefaction and saccharification which respectively produce dextrin and reducing sugars.
Many authors have reported that properties of starch as amylose content, solubility affect the starch behaviour during the enzymatic hydrolysis as well as mechanism of action of amylases.
Starches sorghum were isolated and purified in the laboratory from white and pigmented seeds of cultivars from Algeria (In Salah), and United States of America. Some of their characteristics were determined. Amylases used were from fungal and bacterial sources (α-amylase from Aspergillus oryzae α-amylase from Bacillus subtilis), which possess an important hydrolysis activity. The kinetic studies of enzymatic catalysis had allowed to identify of optimum operating conditions and to calculate enzymatic activities. We also highlight the influence of genotype on starch bioconversion.
Indeed, the composition and concentrations of maltoolisaccharides obtained after amylase hydrolysis were determined using HPAEC-PAD and results of profiles show differences according the sources of starch and amylase. This study is of great importance to consider industrial bioconversion of starches to produce oligosaccharides syrups.